Monday, August 13, 2012

HP LaserJet P2035n -- Fuser Replacement

Fuser P/N is RM1-6405. Proceed as follows:

1) Cartridge

2) Tray 2

3) Left Side Cover
- Front door open.
- Pry at front lip and at centre of top lip to free the cover.
- NOTE: The small claw at the centre of the top lip is liable to break. No real harm is done by that.

4) Right Side Cover
- Open the upper back door (green handle).
- Pry at top and bottom of rear lip.
- Pry at top lip near 'Ready' indicator.

5) Rear Cover
- Five M3x8mm washerhead screws.


6) 'In-The-Way' Cabling
- The cabling that runs across the back of the media feed guide has nothing to do with the fuser's connections, but it must be freed and moved aside.
- Five cable connections. 'Best to disconnect them in sequence from your right to your left. Reconnect them in the reverse sequence.

7) Media Feed Guide
- One M3x6mm black washerhead screw at centre.
- Slide the item to your right to free it.
- NOTE how the item hooks a two-conductor blue cable.

8) Fuser Cabling
- NOTE the unused connectors in the area. They can be a bit confusing at reconnection time.
- One red/blue/green fuser exit sensor cable.
- One two-conductor blue thermistor cable.
- One white wire at the extreme left.
- One two-conductor power connector at the extreme right. (Press its latch tab forward.)

9) Three Gears
- At the right side, there are three gears accessible for removal.
- Frontmost, largest gear -- one claw.
- Upper, smallest gear -- one claw.
- Rearmost gear with 'handle' -- one claw. You may have to nudge the gear CW a bit to get it out. NOTE that there's a timing relationship associated with this gear. The flange on its inboard end is notched to preclude getting it back in place out-of-time with the sector gear below it. A protrusion on the top of the gear aligns with a notch in the gear above it. Here's a view of the three gears.



10) Fuser
- Two M3x8mm washerhead screws.
- NOTE that the two lower screw holes are for the rear cover.
- Slide the fuser out the back.

- - -

Operation Without the Rear Cover

There's a small, white lever at the left side rear of the fuser. That lever must be held down for the printer to operate without the rear cover in place; a jam indication results otherwise.

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Tuesday, July 31, 2012

Lexmark T650 -- Printhead Replacement

Proceed as follows:

1) Cartridge

2) Tray 1

3) Redrive Cap

4) Back Door
- Disengage the support strap from its 'inverted T' slot and pull the door off its hinge pins.

5) Connection Access Cover
- Open it fully and its hinges can be popped free rearward.

6) Lower Rear Cover w/Fuser Access Door
- Three M3x10mm black washerhead threading screws.
- Open the fuser access door -- two claws.
- Pull the cover away at your left and slide the cover toward your right. A downward-pointing hook will slide off a lip at the rear of the chassis.
- NOTE: The above-mentioned hook makes this an awkward part to get back in place. You have to exactly re-create the cover's attitude as the hook was coming off to get it back on again.


7)Redrive Assembly
- Two M3x10mm washerhead threading screws.
- Two outward-hooking claws, left and right side, at about the middle.

8) Left Side Cover -- T650
- Two M3x8mm black washerhead threading screws in the handgrip wells.
- Two M3x10mm washerhead threading screws in deep wells in the side of the toner cartridge cavity.
- Tug on the front lip of the cover to free it; the cover then comes away easily from its hinges.


9) Right Side Cover -- T650
- One M3x10mm washerhead threading screw at the rear.
- Two M3x8mm black washerhead threading screws in the handgrip wells.
- Two M3x10mm washerhead threading screws in shallow wells in the side of the toner cartridge cavity.
- Tug on the front lip of the cover to free it.


10) Fuser Cleaning Wand Cover w/Wand

11) Top Cover
- One M4x10mm pan head threading screw at the right rear.
- Four M3x10mm washerhead threading screws.
- The front edge has to be forced up past the rear edge of the upper front door. NOTE: It's a bit difficult to get this cover levered back into place at the front, but it is doable without damaging anything.

12) System PCA Enclosure Cover
- One M3x6mm black pan head screw at the upper rear.
- Loosen five M3x6mm black pan head screws.

13) Printhead
- Cable connection 'JGALV01' at the System PCA. (Cut ty-wraps A/R to free the cable.)
- One cable connection at the top left of the printhead.
- Three M3.5x13mm pan head threading screws w/captive washers.

- - -

Optical Skew Adjustment

Note that the printhead pivots on a reference pin at about the mid left-rear. That pivoting is what makes optical skew adjustable. The adjustment range is determined by the printhead fastening hole at the right side end of the printhead. There are two ways to deal with the optical skew adjustment.

Quick Method

For a quick way to adjust optical skew, simply fasten the printhead in place with the adjustment at its obvious design-centre, as in the following photo.


For most applications, the adjustment will be close enough to correct, and perfectly acceptable to the user.

'Correct' Method

To get optical skew set to perfection, proceed as follows:

1) Install printhead with the three screws not fully tightened.

2) Reinstall cartridge and tray 1.

3) Start the printer in DIAGNOSTICS mode. (Hold 'down arrow' and 'right arrow' keys while powering on.)

4) Select REGISTRATION.

5) Scroll to 'Quick Test' and select it.

6) The print you get has marks at the upper corners that make it easy to see if the optical skew adjustment is off. Do the adjustment by trial-and-error, then tighten the three mounting screws when it's right. Here's a view of a Quick Test page showing correct optical skew adjustment.


- - -

Laser Beam Deflection in the T650

The T650's printhead has no polygonal mirror and motor. Instead, it employs an oscillating mirror to deflect the laser beam. Here's a photo of it.


The mirror is right at the centre of that photograph. It pivots slightly on a vertical axis. An alternating magnetic field causes it to oscillate through the angle necessary for laser beam deflection.

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Wednesday, May 23, 2012

HP LJ P3005 -- Fuser Access

When a P3005 needs a fuser, it's likely to need a set of four associated gears as well. See this post for information on the gear kit.

The P3005's fuser is pretty easy to deal with. Proceed as follows:

1) Cartridge

2) Tray 2

3) Rear Door Fully Open
- Tug it open forcefully and it will open all the way.

4) Rear Cover w/Door
- Two M4x10mm pan head threading screws.
- A claw at either side of the Tray 2 cavity. Raise the small door across the rear of the tray cavity to see them.

5) Mains Receptacle Bezel

6) Duplexer Input Guide (The black plastic 'ramp' at the rear.)
- Two claws -- they have ‘handles’ extending rearward.
- Push up on the claw handles and pull the guide toward you.


7) Fuser Power Cable
- Disconnect it and free it from its restraint.

8) Exit Sensor Cable (Violet)

9) Thermistor Cable (Yellow and white.)
- Free the cable from its white restraint. The restraint can be unlatched with a fingernail or a small screwdriver.

10) Fuser
- Three prominent M4x10mm pan head threading screws.
- One M3x6mm pan head screw w/captive star washer. It’s in a recess at the fuser’s lower right.
- Tug on the fuser's cables to dislodge it.

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Tuesday, May 15, 2012

Repairing Bent Plastic Parts

Pictured below is a bent paper-out sensor toggle/flag in a Lexmark T630.


It's often possible to repair that sort of thing by heating the part with a lighter or a heat gun and straightening it. I did that to the pictured part and got a reasonably good result, like so.


You have to take great care not to overdo the heat. The plastic needs to be heated just to the point where it can be nudged back to its correct shape, but no hotter -- too much heat is likely to spoil the job.

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Monday, May 14, 2012

Roller Clutch Service

Pictured below is a roller clutch from an HP LaserJet 4100's paper feed assembly.


Note the rollers in the bore that give the clutch its name.

Roller clutches all free-wheel in one direction of rotation, and grip the shaft they're on in the other direction. The clutch pictured was slipping badly in its grip direction. When I was trying it by hand with the assembly out of the printer, it would only grip intermittently; mostly it just free-wheeled in both directions.

These clutches are long lasting, but they will get gummy inside as they age, and that causes them not to grip. To restore a slipping clutch, soak it in Varsol for a few minutes to dissolve the gum, dry it thoroughly, then lubricate it with WD-40 on reassembly. Odds are good that the clutch will work fine. The one in the photograph responded nicely to that treatment.

Roller clutches are widely used, and none are immune to gumming and slipping. The result is invariably intermittent, baffling paper jams. It's a good practice to familiarize yourself with where the roller clutches, if any, are in any given machine.

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Monday, May 7, 2012

Lexmark T64X -- MP Feeder w/Snags

We ran into a T640 giving frequent jams from the MP Feeder. The cause turned out to be a factory defect in the moulding of the lower deflector. Here's a photograph of the flaw.



It's not a great photo, but note the corner of that nearest rib -- it extends vertically a tiny bit above the leading edge of the upward-curving ramp portion of the rib. All the ribs were like that, and jammed sheets showed evidence of snagging at the position of the second rib from the right.

Cutting off the tiny upward projections with a sharp utility knife, and filing a bit to round over the corners fixed it. Here's a view of the part after cutting and filing.


I imagine this flaw results from misaligned moulding equipment. There are probably many such flawed MP Feeder lower deflectors out there.

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Wednesday, May 2, 2012

Lexmark T65X -- MP Feeder Pickup Solenoid


We've seen several inoperative MP Feeders on T65X machines recently; replacing the pickup solenoid fixes the problem. A service replacement solenoid's P/N is 40X6994. A replacement procedure is included here, toward the end of this note.

- - -

It looks like the MP Feeder's pickup solenoid is a bit of a weak point on the T65X -- the redesigned pickup clutch appears to be the reason for it.

T65X MP Feeder Operation

The T65X MP Feeders don't employ a wrap-spring clutch, as all the earlier T models and the Optra S did. They have a spring-biased clutch-gear with an arc of missing teeth for a disengagement position. The bias torque that engages the clutch-gear with the drivetrain when the solenoid is energized is derived from the feeder's elevator flap spring, via the slope of the elevator cam's lobe profile. Here's a view of the arrangement from in back.



That compressed elevator flap spring is providing a lot of bias torque to the clutch. Consequently, the cam's disengagement ledge is pressing quite forcefully on the solenoid's flapper-end. A subpar solenoid that lacks sufficient electromagnetic force to pull its flapper away  from the cam's ledge will appear to be inoperative.

- - -

Early Solenoid

[MONDAY, AUGUST 20, 2012 -- The following has been revised based on current information.]

It appears that the original solenoid was P/N 40X4365. That solenoid has a 12W coil. The new solenoid, P/N 40X6994, has a 14.4W coil. The new solenoid is bulkier, and more difficult to get into place because of that, but it's a better solenoid for operating the strongly biased clutch on the T65X. Here's a view of the two different solenoids.


At the left is P/N 40X4365, the old, 12W solenoid. At the right is P/N 40X6994, the new 14.4W solenoid. Note the bigger coil/frame on the new solenoid. That makes it a snug fit where it goes, but it does fit in place, and the extra force it has for pulling the flapper is just what's needed for the clutch it works with.

- - -

Solenoid Replacement

Proceed as follows:

1) Toner Cartridge

2) Paper Tray (Tray 1)

3) Back Door
- Disengage the support strap from its 'inverted T' slot and pull the door off its hinge pins.
 
4) Connection Access Cover
- Open it fully and its hinges can be popped free rearward.

5) Lower Rear Cover w/Fuser Access Door -- T650
- Three M3x10mm black washerhead threading screws.
- Open the fuser access door -- two claws.
- Pull the cover away at your left and slide the cover toward your right. A downward-pointing hook will slide off a lip at the rear of the chassis.
- NOTE: The above-mentioned hook makes this an awkward part to get back in place. You have to exactly re-create the cover's attitude as the hook was coming off to get it back on again.

5) Lower Rear Cover w/Fuser Access Door -- T652
- Two M3x10mm washerhead threading screws.
- Open the lower door.
- Two M3x6mm washerhead screws.
- Open the fuser access door -- two claws.
- Tip the cover rearward and lift it off of two hooks at the bottom.

6) Left Side Cover
- Two M3x8mm black washerhead screws in the handgrip wells.
- Two M3x10mm washerhead screws in deep wells in the side of the toner cartridge cavity.
- T650: Tug at the front lip and two upper claws and one lower claw will pop free. The cover's rear hinges come away easily.
- T652: Similar, but there are six claws, and one of them can be quite tenacious. First, pry at the angled upper front lip to free the upper two claws. The troublesome claw is located roughly 3" from the front and 3" from the bottom. You may have to reach in with a long narrow-bladed screwdriver to pry it loose.

7) System PCA Pan Cover
- One M3x6mm black pan head screw at upper rear.
- Loosen five M3x6mm black pan head screws.


8) MP Feeder Platform
- Flex the slide pins' ways to free the slide pins.
- Tip the platform up to vertical and pull it off its hinge pins.

9) MP Feeder Door
- Pry the support arms to pop their pins out of their ways.
- Slide the door leftward off its hinge pins.

10) Upper Deflector
- Pull the extreme left end of the piece toward you and force the deflector to the right. It can then be unhooked at the right end.
- NOTE that reinstallation of this item is complicated by a downward-projecting spike near its left side end. You really have to flex the thing to get it to go back into place.

11) Solenoid
- One cable connection. (Two-conductor yellow cable.)
- One M3x10mm washerhead threading screw.
- Extract the solenoid/cable.

NOTE: The replacement solenoid has a longer coil/frame than an early solenoid, and is difficult to get in place without loosening off  the MP Feeder Lower Deflector/Elevator Flap Assembly. Remove the two screws that fasten the left side end of the assembly, and you'll be able to gain sufficient clearance to get the new solenoid in place.


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Tuesday, May 1, 2012

Lexmark T64X -- Dark Background on Prints

The effect pictured below is caused by the printhead.


The giveaway is the appearance of sometimes missing, sometimes prominent scan lines among all the murk. That's evidence of the laser diode in the printhead acting up.

Try reseating the printhead's cable connections. If that doesn't work, replace the printhead. Printhead P/N is 40X0062. That P/N is good for all the T64X models.

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Wednesday, April 25, 2012

Lexmark T65X -- Drivetrain/Motor Assembly Access


In the T65X machines, the developer drive is integrated with the main drive train and motor assembly; there's no need to remove the developer drive first to get at the main drive. Also, the power connection at the System PCA is new; I've included photos of it further down. Proceed as follows:

- - -

1) Toner Cartridge

2) Paper Tray (Tray 1)

3) Back Door
- Disengage the support strap from its 'inverted T' slot and pull the door off its hinge pins.
 
4) Connection Access Cover
- Open it fully and its hinges can be popped free rearward.

5) Lower Rear Cover w/Fuser Access Door -- T650
- Three M3x10mm black washerhead threading screws.
- Open the fuser access door -- two claws.
- Pull the cover away at your left and slide the cover toward your right. A downward-pointing hook will slide off a lip at the rear of the chassis.
- NOTE: The above-mentioned hook makes this an awkward part to get back in place. You have to exactly re-create the cover's attitude as the hook was coming off to get it back on again.

5) Lower Rear Cover w/Fuser Access Door -- T652
- Two M3x10mm washerhead threading screws.
- Open the lower door.
- Two M3x6mm washerhead screws.
- Open the fuser access door -- two claws.
- Tip the cover rearward and lift it off of two hooks at the bottom.

6) Left Side Cover
- Two M3x8mm black washerhead screws in the handgrip wells.
- Two M3x10mm washerhead screws in deep wells in the side of the toner cartridge cavity.
- T650: Tug at the front lip and two upper claws and one lower claw will pop free. The cover's rear hinges come away easily.
- T652: Similar, but there are six claws, and one of them can be quite tenacious. First, pry at the angled upper front lip to free the upper two claws. The troublesome claw is located roughly 3" from the front and 3" from the bottom. You may have to reach in with a long narrow-bladed screwdriver to pry it loose.

7) System PCA Pan Cover
- One M3x6mm black pan head screw at upper rear.
- Loosen five M3x6mm black pan head screws.

8) System PCA/Pan Assembly
- One ty-wrap.
- Twenty cable connections.
- Four M3x10mm washerhead threading screws. (They're roughly at the corners of the PCA.)
- Pull the assembly straight away to disconnect J23, the POWER connector. You may have to wiggle the item a bit to get it to let go. The connection is near the lower rear of the PCA. Here's a view of it.


It's much like the PCA connection style that HP has used in many models. Here's a view of the connector pins with the System PCA removed.



It's something to be mindful of when it's exposed -- the pins are easily bent.


9) Vertical PTO Shaft w/Spring
- Pull it out the bottom of the machine.

10) Fuser Drive Engagement Link
- Gently pry its upper end free of the engagement lever. Rotate the link to where its lower end will come free.

11) Drivetrain/Motor Assembly
- One M3x10mm washerhead threading screw at the rear.
- One M3x10mm washerhead threading screw at the lower front.
- Two M3x10mm washerhead threading screws high up.
- One cable connection at the motor's rear.


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Monday, April 23, 2012

A Visitor to the Building


I stepped out for a smoke, and this little guy was creeping up by the door frame. Maybe we can sell him a nice LaserJet 4L -- the speed would suit him fine.

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HP LaserJet 2200 -- Tray 2 Pickup Roller & Separation Pad

Part Numbers

Pickup Roller: RB2-6304

Separation Pad: RB2-6349

- - -

Pickup Roller Replacement

1) Cartridge

2) Tray 2

3) Set the printer on its rear.

4) Left Side Bearing
- Unlatch its arm and swing the arm ninety degrees towards you.
- Remove the bearing.

5) Right Side Bearing
- Unlatch its arm and swing the arm ninety degrees towards you.
- Slide the bearing rightward until it's stopped.
- Swing the arm fully up toward the printer and slide the bearing fully to the right.

6) Pickup Roller w/Slip Rollers
- Tip out the right side end of the roller to remove it.
- TRANSFER the slip rollers to the new pickup roller. Missing slip rollers will render Tray 2 inoperative. Replacement rollers are P/N RB2-2892.

- - -

Separation Pad Replacement

1) From underneath, free two claws accessible through rectangular openings.

2) Free two claws at the front face of the separation pad. Lift the pad off its steel bracket.

3) Transfer the spring to the new separation pad. A replacement spring is P/N RS6-2021.

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HP LaserJet 2200 -- Fuser Access

Fuser P/N is RG5-5559. Proceed as follows:

1) Cartridge

2) Tray 2

3) Interface Connections Cover
- Press two latch buttons at the cover's rear. The cover can then be swung away and removed.

4) Right Side Cover
- Under the cartridge door, there's a rectangular latch button. Push that down far enough and the cover can be slid forward about 5/16" to free it. There's a small claw at the front just inside the Tray 2 cavity that you may need to pry loose.

5) Rear Cover/Door
- Open the rear door part way. There's a pivoting guide rib array inside that can be unhooked to permit the door to drop open all the way.
- Two M4x10mm pan head threading screws.
- Two claws just inside the Tray 2 cavity.

6) Duplex Infeed Guide
- Two M4x14mm YZD pan head threading screws w/captive washers.
- Two small, outward-gripping claws, left and right sides.
- NOTE the three round nubs at the inner bottom of the part. Those must engage first at re-installation, then the part can be tipped back into place.

7) Fuser
- Three cable connections.
- One M4x10mm pan head threading screw.
- One M3x6mm pan head screw w/captive star washer.

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Wednesday, April 18, 2012

Lexmark X342 -- Fuser Replacement

The left and right side covers, and the rear cover have to come off for access to the fuser.

Fuser P/N is 40X4194. Proceed as follows:

- - -

1) Cartridge

2) Paper Tray

3) Paper Tray Rear End Concealment Cover
- Pinch inward at its sides and tip it up to remove it.

4) Lower Right Side Cover
- One M3x9mm washerhead screw in front behind the cartridge access door.
- Swing the cover open, pry it free of its lower hinge pin, lift to get it off its upper hinge pin.

5) Upper Right Side Cover
- One M3x9mm washerhead screw in front behind the cartridge access door.
- Two M3x8mm washerhead threading screws at the back.
- Tip the cover up forcefully to remove it.

6) Left Side Cover
- Two M3x9mm washerhead screws in front behind the cartridge access door.
- Three M3x8mm washerhead threading screws at the back.
- Lay the machine on its right side. (MIND the ADF -- it's likely to swing up.)
- Two claws in front.
- Pry/yank the lower end of the cover away and tip it up to remove it.
- Set the machine back upright.

7) Rear Cover
- Back door open.
- Place something like a 1/2" thick catalogue on the scanner's platen glass to keep the ADF assembly propped up a bit.
- Two M3x9mm washerhead screws at either side of the back door.
- Two claws, either side, low down.
- NOTE: The claw at the right is difficult to release because of a sheet metal piece that's in the way. One M3x8mm washerhead screw to remove the sheet metal piece.
- Tip the cover away.
- RE-INSTALLATION NOTE: Make certain that the cover's upper edge is fully hooked in place before reseating the lower claws.

8) Delivery Assembly
- Two M3x6mm washerhead screws at left and right, high up.
- One M3x9mm washerhead screw at lower left.
- RE-INSTALLATION NOTE: This item comes out easily, but it can be difficult to get back in place. It must be presented straight and level to where it sits, else it will fight you.

9) Fuser
- Exit sensor cable connection at J10.
- Thermistor cable connection at J15.
- Pull the two cables inboard through their horizontal rectangular opening in the sheet metal.
- Two M3x9mm bright washerhead screws at sheet metal tabs, left and right.
- Pull the fuser out far enough to get at the AC spade terminals.
- NOTE: The spade terminals are a lock-on type that can be aggravating to disconnect. The female terminals have a lock-nub that must be pressed with the point of a mechanic's pick to disengage it from the male terminal. You may have to slide back the insulating sleeve to do this. The insulating sleeve on the black wire gets baked and embrittled; you may have to ruin it to get the terminal off.
- RE-INSTALLATION NOTE: The blue and black wires must lie fully within their channel at the left side end of the fuser; there's no clearance for them otherwise. Mind the sheet metal tab at the left side end; it's easy to get it in behind its mounting tab, instead of on the outside of it.

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Wednesday, April 4, 2012

Lexmark T65X -- Fuser Cleaning Wand Cover Defect

The fuser cleaning wand cover on T65X machines employs the same wand-holding claws as the cover on T64X printers. The claws are exhibiting the same defect as they have on T64X printers. See this post.

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Monday, April 2, 2012

HP LaserJet 1100 -- Pickup Roller, Separation Pads and Feed Roller

Part Numbers

Pickup Roller: RB2-4026

Main Separation Pad: RF5-2886

Left and Right Sub-Pads Kit: RY7-5050[1]

Feed Roller: RB2-3912

- - -

Introduction

In the 1100 printers, items that commonly need attention are:

a) Pickup Roller.

b) Separation Pads.

c) Sticky Pickup Solenoid.

d) Glazed Feed Roller.

This procedure deals with all four.

[Note: 'Damper Rods' are the black plastic links attached to the door.]

It's quite a teardown to get at everything. Proceed as follows:

- - -

1) Cartridge

2) Side 'Pods'
- Insert a medium-size plain slot screwdriver at the top of each pod and pry outward. The pods will pop free.

3) Left Side Damper Rod
- Disengage the door end of the damper rod. There's a claw on the white anchor block. Press that and the anchor block can be slid out of its channel.

4) Right Side Damper Rod
- Same as left side.

5) Face-Up/Face-Down Deflector
- There's a small claw at its left side end. Push that leftward and the left side end of the deflector can be raised. At the right side end, push down on the wire detent bail, and the deflector can be slid out leftward.

6) Door
- Two M4x8mm black pan head threading screws.
- Slide the door off the hinge, while observing how it mates with the hinge. Reinstallation can be a bit puzzling if you're unfamiliar with the door's fit on its hinge.
- Tie the door hinge in its raised position with a garbage bag tie. It makes a nuisance of itself if left free to flop about.

7) Front Cover
- Two M4x10mm bright pan head threading screws high up.
- At the lower rear corners of the cover, flex the cover to free it from its retaining studs. The cover can be tipped up somewhat and eased away frontward.
- Slide the damper rods into the printer.

8) Rear Cover
- Two M4x10mm bright pan head threading screws in deep wells.
- Raise the DIMM slot access cover/door. Remove DIMM if present.
- One M3x6mm bright pan head screw w/captive star washer.
- Flex and tip away the cover as you did with the front cover.
- NOTE: At reinstallation, the side guides on the paper supply chute will tend to interfere with this cover. Nudge/pry A/R to get the cover to seat.

9) Paper Supply Chute
- Pry up gently at either side to free it.
- AT REINSTALLATION, watch that the black mylar sheet in front goes straight into place, and won't interfere with paper motion.

10) Printhead Cover
- One cable connection at control panel.
- One M3x6mm bright pan head screw w/captive star washer at left side below control panel.
- Two M4x12mm black pan head threading screws.
- Two claws.

11) Pickup Roller Assembly
- Two M3x6mm bright washerhead screws below the printhead deck.
- The assembly slips off the end of the pickup shaft rightward.
-NOTE: At reinstallation, there are two locating nubs at the upper rear of the white 'ears'. Make certain those nubs are correctly seated before tightening the screws.

12) Printhead w/Sheet Metal Mounting Deck
- One foam rubber dust seal.
- Two cable connections.
- Two M3x6mm bright pan head screws w/captive star washers.
- Two M4x10mm bright pan head threading screws at the rear of the deck.
- Lift the item away.

13) Lift Plate
- Manually actuate the pickup solenoid,[2] and turn the geartrain to get the pickup shaft's cam around to where the cam follower is free of the cam.
- Raise the lift plate until the flats on its left side pivot pin permit it to come out and away.
- NOTE: At reassembly, turn the geartrain again in its correct direction to get the cam back to its normal at-rest position. It will be easier to get the pickup roller assembly back in place.

14) Main Separation Pad
- One white clip.
- TRANSFER the spring to the replacement pad.

15) Left and Right Sub-Pads
- Pluck up their front edges with a fingernail.

- - -

Feed Roller

Glazed feed rollers will not feed paper reliably. If at all in doubt about the feed roller's condition, replace it before reassembling the machine.

Proceed as follows:

- - -

1) Drivetrain (if you haven't already removed it to inspect the pickup solenoid)
- Motor cable connection at rear of motor.
- One M3x6mm bright pan head screw w/captive star washer at lower rear.
- Two or three M4x10mm bright pan head threading screws.

2) Cable Clamp
- Just below the pickup solenoid, there's the mounting stud of a cable clamp. Force it out of place.

3) Lay the printer on its left side.

4) Formatter Pan
- Three M3x6mm bright washerhead screws.
- Swing the pan down from its right side end.

5) Cabling
- Three cable connections.
- NOTE that the white side of the amber cable's end faces up; the contact side faces down.
- Set aside the formatter pan.

6) Amber Cable
- Force the cable's cover rearward to remove it.
- Free the violet cable from two restraints.
- One M3x6mm bright pan head screw w/captive star washer.
- Free the amber cable and pull it out to the front to get it out of harm's way.

7) Amber Cable Trough
- There's a latch tab near the centre rear of the part. Pry that up and you can slide the part rearward to remove it.

8) Engine Controller Assembly
- Fuser power cable connection at right side.
- Fuser thermistor cable connection at left side.
- Pickup solenoid cable connection.
- One M3x6mm bright pan head screw w/captive star washer at right side ground continuity strap.
- Four M4x10mm bright pan head threading screws -- two at the rear; two underneath at the front.
- Free the rear of the assembly and pull it away slightly.
- Two cable connections.

9) Feed Roller Gear/Clutch/Spring
- Two claws.

10) Feed Roller Assembly
- Lay the printer upside down.
- Pry out the white feed roller bearing at the left side. It has two claws holding it in place that will pop free when you pry.
- Two sensor cable connections. Free the long cable.
- Two M4x10mm bright pan head threading screws.
- MIND the paper-out sensor's toggle as you take away and reinstall the assembly.
- NOTE the tab at the front of the assembly. That must engage correctly with its slot on reinstallation.
- Clean the bearings w/methyl hydrate. No lubrication is needed.

- - -

Notes:

[1] For what it's worth, the individual parts are:
  • Left Side Sub-Pad P/N RF5-2820
  • Right Side Sub-Pad P/N RF5-2821
[2] On a machine the age of an 1100, it's a good idea to remove the drivetrain and check that the solenoid isn't sticky. See this post.

Drivetrain removal is straightforward -- one cable connection at the rear of the motor, and three screws.

When unplugging the solenoid, take care that the connector shell doesn't come away off the board along with the cable end connector.

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Friday, March 30, 2012

Lexmark X264dn -- LVPS/HVPS Removal

We had to replace one of these recently to solve a 'blank prints' problem; the machine was printing entirely blank pages with no error indication. The prints exhibited a slight bit of grey background.

Part number is 40X5361 (110V).

The unit resides above the paper tray cavity at the rear of the printer. Proceed as follows:

- - -

1) Cartridge

2) Paper Tray

3) Rear Door
- Open it to about a forty-five degree angle, and tug forcefully to pop it off its hinges.

4) Rear Cover
- Two M4x8mm bright washerhead threading screws.
- Pry to free its upper edges at left and right.
- Tip it out and lift its lower hooks off their perches.

5) Front Scanner Cover
- Tug/pry on it. Its four concealed claws will pop free.

6) Left Side Scanner Cover
- One M3x8mm bright washerhead threading screw at the front.
- One M3x8mm bright washerhead threading screw at the rear.
- Tip the bottom of the cover outward to free the cover.

7) Lay the machine on its right side.

8) Left Side Cover
- One M3x6mm bright washerhead screw at lower front.
- Two claws underneath.
- Tip the cover outward and force it upward to free two hook-tabs at the cover's upper lip.

9) Fuser Power Connector
- Two-conductor black cable connection at left side, lower rear.

10) Right Rear Foot
- Two M3x6mm bright washerhead screws.

11) LVPS/HVPS
- Four M3x6mm bright washerhead screws -- two underneath; two at the rear.
- One white-shelled spade connector at left side.
- Three cable connections at PCA.

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Tuesday, March 27, 2012

Lexmark Optra E310 -- Pickup Roller and Separation Pads Replacement

It's a straightforward job, but it's quite a teardown to get at the parts.

- - -

Part Numbers

Pickup Roller Assembly: 12G0067

Main Separation Pad: 12G0062

Left Side Sub-Pad: 12G0119

Right Side Sub-Pad: 12G0120

- - -

Proceed as follows:

1) Front Face-Up Delivery Door
- Unlatch it, and flex it to remove it from its hinges. This is done to make it easy to dislodge the front door when needed. The door interferes with removing the left and right side covers.

2) Cartridge

3) Rear Cover
- Three M3x10mm bright washerhead threading screws.
- Two claws.
- Force the cover upward a bit to unhook it.
- AT REINSTALLATION, mind the parallel interface connector's bails.

4) Top Cover
- Two M3x10mm bright washerhead threading screws.
- The cover lifts away easily.

5) Left Side Cover
- One M3x10mm bright washerhead threading screw at the lower rear.
- One M3x10mm bright washerhead threading screw securing the door's restraint strap.
- One claw next to the printhead.
- Pry at the lower rear to free a retaining nub from a hole in the chassis.
- The lower front is held in place like the lower rear is. The door makes it a bit awkward to get the lower front freed. Dislodge the door's hinge if needed to get the cover off.

6) Right Side Cover
- One M3x10mm bright washerhead threading screw at the lower rear.
- Similar to left side cover.

7) Paper Supply Chute
- Lift it out.
- AT REINSTALLATION, watch that the black mylar sheet in front goes straight into place, and won't interfere with paper motion.

8) Motor/Drivetrain Assembly
- Note the wire and strap connections, and the 'Z'-shaped cable retainer.
- Six M3x10mm black washerhead threading screws.
- Pull the assembly out a way.
- One cable connection at motor.

9) High Voltage Power Supply (HVPS)
- Three cable connections at the upper edge.
- Five M3x10mm black washerhead threading screws.
- Pull the HVPS out a way.
- One cable connection.

10) Spring-Loaded 'Bullet' Contacts
- With the HVPS removed, four contacts are free to come out. Remove them for safe keeping. NOTE that the lower one of the four has a longer spring on it.

11) Printhead w/Mounting Deck
- This item can't be removed entirely because of the way that it's cabled, but it needs to be moved aside for access to the paper pickup area.
- Six M3x10mm black washerhead threading screws, three per side.
- There's a 'hole & stud' retention in front of the fan. Free that and the unit can be lifted away, and lain down behind the printer.
-REASSEMBLY CAUTION: The two upward-pointing 'ears' on the pickup roller assembly must end up in front of the lower rear ledge of the printhead deck. The printer will not feed paper otherwise.
- CHECK that the pickup solenoid's flapper hasn't been dislodged after reassembly.

12) Lift Plate Springs
- Unhook them.

13) Pickup Clutch
- One e-clip.

14) Left Side Pickup Shaft Bearing
- Black plastic 'rectangular' baffle plate -- a springy claw is securing it.
- One M3x8mm black pan head threading screw at the ground contact strap.
- Swing-latch bearing -- remove it.

15) Pickup Roller Assembly
- Shift it rightward, free its left side end and remove it.

16) Lift Plate
- Raise it until the flats on its right side pivot pin permit it to come out and away.

17) Main Separation Pad
- Tip it up to where it can come out.
- TRANSFER the spring to the relacement pad.

18) Left and Right Sub-Pads
- A slim spring hook is helpful for unclipping their lower rear edges.

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Friday, March 23, 2012

Lexmark X544 -- Fuser Removal

Fuser removal in the X544 is not pleasant. You'll need a spring hook. Proceed as follows:

1) Paper Tray

2) Front Door Open

3) Flatbed Scanner
- Raise it. There's a latch-button at the right side with a 'toner' symbol on it. Squeeze that and lift firmly. The flatbed will lift and latch. Squeeze the button again when you need to unlatch and lower the flatbed.

4) Right Side Cover
- Press two green buttons. The cover swings down and comes away from its hinges easily.

5) Left Side Cover
- One M3.5x6mm pan head threading screw in centre of handgrip.
- One M3.5x6mm pan head threading screw below line cord receptacle.
- One M3x6mm washerhead screw above and inboard of line cord receptacle.
- One M3.5x6mm pan head threading screw by upper outboard corner of fan.
- Flex the cover outward below and behind the on/off switch to disengage a tab at the bottom front of the cover. The cover can then be fully eased off.

6) Fuser Power Cable
- Disconnect blue and white cable from rear of power supply at left side of printer. Free the cable from its restraint.

7) Fuser Frame Screw
- One M3.5x9mm pan head screw w/captive washer directly above fuser motor.

8) Thermistor Cables
- Two small two-conductor cable connections at right front of fuser; one black, one white.

9) Timing Belt
- CAUTION: Try to disturb this belt as little as possible when dealing with it. Should it get dislodged from its path inside the machine, you could be in for an ordeal. NOTE that it's toothed on both sides.
- It's at the extreme upper left of the fuser. Dislodge it from its pulley; you'll have to pry it off with a small screwdriver.
- AT REINSTALLATION, you'll need a spring hook to get the belt back in place.

10) Retention Springs
- There are two extension springs securing the upper ends of the fuser's frame. Unhook them.
- AT REASSEMBLY, make sure the springs are perched upright so they can be hooked for reattachment.

11) Exit Sensor
- Tip the fuser outward. At the sensor's underside there's a thin black retention plate. Pry that off and the sensor can be freed from its cut-out in the sheet metal.
- Free the sensor's cabling from the fuser's frame.

12) Fuser
- Tip the fuser out fully, slide it leftward a bit and it can be lifted off the rod that it pivots on (note the flats). Coax the blue and white power cable out along with the fuser.
- NOTE that at reassembly, the blue and white power cable goes inboard of the fuser's pivot rod.

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Thursday, March 15, 2012

Oki PM 3410 -- Revisions 'A' and 'B' Power Supply Replacement

A Pacemark 3410's revision level is given by the fourth character of the printer's serial number. If you have a revision 'A' or 'B' printer that needs a power supply replacement, you'll have to get a revision 'C' power supply (P/N 42312551); the earlier revisions are no longer available. There's an issue of connector compatibility that arises with that; there are two ways to deal with it.

a) Replace the two cables that connect to the power supply with revised, compatible cables. The part numbers are 41998701 (9 pin cable) and 41998801 (13 pin cable).

Obtaining those cables might be problematical. We tried recently to get a set, and Oki couldn't come up with them.

b) Swap the two connectors involved on the power supply. The circuit boards are of simple, cheap construction without thru-connects, so it's very easy to unsolder components without harm to the board.

- - -

The mechanism has to come out of the chassis pan for access to the power supply. Proceed as follows:

1) Access Cover
- Tip it up from the rear. When it's fully opened, it can come away.

2) Platen Knob

3) Pull-Up Roller Assembly
- Open the upper rear acoustic cover.
- Tip the pull-up roller assembly rearward to unclip it.

4) Top Cover
- Two M4x10mm bright pan head screws w/captive washers at the rear.
- Tip the cover up from the rear and it unhooks easily from the front.
-NOTE: The two nuts for the M4 screws sit loose in pockets. They're easily dislodged and lost. Best to remove them with a magnet and keep them with the screws.

5) Ribbon Cartridge

6) Control Panel w/Sheet Metal Mount
- One ZIF cable connection -- CN10.
- Five M3x6mm washerhead screws.
- Two cable connections -- CN11 and CN12.

7) Mechanism Cabling
- Two cable connections high up on interface connector PCA -- CN102 and CN103.
- Line feed motor connection at lower right of PCA -- CN9.
- Fan connection -- CN8. Check that this cable is free of other cabling.
- Two carriage motor connections -- CN1 and CN5.
- Carriage cable connection at upper edge of PCA -- CN2.
- Cable connection at lower left side of PCA -- CN4.

8) Mechanism
- Mechanism base fasteners -- three M4x12mm pan head screws w/captive washers, plus three steel clamp-plates. A magnetic retrieval tool is helpful.
- Mechanism rear edge fasteners -- three M4x8mm pan head screws w/captive washers.
- The mechanism is free to be lifted out of the chassis pan.

9) Power Supply
- Two cable connections.
- Four M4x8mm pan head screws w/captive washers.
- The unit's rocker switch, and a sheet metal projection at the lower right rear can be a bit of a hindrance to unit removal. Lift the left side end of the power supply slightly and it comes out easily.

- - -

If you have the replacement cables, it's pretty obvious how the old cables are removed and the new ones are installed.

If you're swapping connectors, the connectors can be removed without dismounting the circuit boards from their frames. To dismount a circuit board to make connector installation easier, remove the insulation sheet and six screws. There are two cable connections to be disconnected.

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Wednesday, March 14, 2012

Lexmark T65X -- MP Feeder Booby Trap

I had the MP Feeder lift plate assembly off a T652n to get at a label that was stuck in the infeed chute. When I put it back on and went to test the machine, the MP Feeder was inoperative. It turned out that I'd dislodged the MP Feeder solenoid's flapper, like so.

It's really easy to do that. Be careful when you're in that area, and confirm that the flapper is ok before buttoning things up. Here's a view of the flapper seated correctly.

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Saturday, March 10, 2012

The 'Training' Fallacy

In the printer service field, we hear endlessly about technician 'training' and technician 'certification'. There's an outfit known as CompTIA[1] that's spun quite a business out of that theme -- the PDI+ rack..., er, 'certification'.

If I may be blunt, 'training', as it's commonly understood and practised, is a worthless load of rubbish, unfit for human consumption. 'Training' is for puppy dogs, to acquaint them with the idea that they're not to shit inside the house. One cannot 'train' a technician to diagnose and correct printer troubles in any such fashion. The notion is patently false, ludicrous and an insult to technicians' intelligence.

With that little rant out of the way, I'll elaborate.

- - -

On this blog, I post information and instruction; information and instruction in plain English that I can vouch for because I've personally verified every word of it. Information and instruction that some have found to be helpful. Here's a small example. It's a brief post I did about getting an Okidata printer's full control panel functionality restored when it's been suppressed:

- - -

Oki 320/1 Turbo, 420/1 -- Menu Mode Unavailable

If you can't get at the Menu Mode by pressing SHIFT + MENU, it's likely because the Operator Panel Function item in the menu has been set to Limited Operation.

Load continuous forms and switch off the printer. Power on while holding SHIFT + MENU. The printer will come up in Menu Mode. Operator Panel Function is an item in the Set-Up group. Change it to Full Operation to restore complete functionality.

- - -

Here's the response I got to that from 'Anonymous':

thank you!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


thank for ending 2 weeks of endless searching, and im the tech savey one here

- - -

My point here is that Anonymous did not need 'training'. What he needed was information. Given that information, he was able to solve his problem and move on.

- - -

Conventional training, by and large, is neither informative nor instructive. It consists chiefly of shallow 'data' that leaves its recipient no more enlightened about the subject matter than before.

The PDI+ programme is accompanied by a massive PDF 'textbook' that purports to teach printer service. The book spews all manner of 'data' without ever connecting that data to the problem of diagnosing and correcting printer faults. One is told how the machines work. One is not told how the machines 'work' when they're not working right, and how they work when they're not working right is what the technician is grappling with all the time.

The textbook tells of rollers; e.g. pickup rollers that get a sheet of paper launched out of a paper tray. Consider, what is the quality that such a roller must possess in order to function reliably? It must possess traction. I did a search through the entire book for an occurrence of the word 'traction', and the word appears not once. A discussion of rubber rollers that fails to even once mention 'traction' reveals itself to be a hollow fraud.

The textbook tells of clutches. Clutches of various types are widely used in printers, and they're prone to intermittent failure as they age and wear. They tend to cause mystifying trouble symptoms. The book offers no information about clutch failure mechanisms, about how those failure mechanisms express themselves or about how to identify and isolate clutch failures.

A technician can study the textbook, sit and pass the multiple-choice exam and be certified without ever having really learned anything that would help him repair a malfunctioning printer. The training and certification testing are worthless. Actually, they're worse than worthless because they consume resources to no good effect that could could be put to profitable use.

Here's an example of the sort of printer service that all too often transpires in the field. I don't know whether the original technician on the call was PDI+ certified or not, but the outcome he got was about par for many technicians, certified or not. We see this sort of thing quite routinely.

Last week, a computer service firm brought a LaserJet 4200 to our shop that they'd tried and failed to fix. The problem was intermittent paper jams. They'd replaced many components to no avail; they'd even replaced the DC Controller. I took the right side cover off and removed the tray 2 pickup solenoid to examine it. The solenoid was sticky, as described in this post. The repair method described in that same post got the machine working reliably. The knowledge I used to effect that repair did not come from CompTIA, or from any of the OEMs.

If CompTIA means to be helpful with its PDI+ programme, it needs to rethink 'training' from the ground up, and investigate what printer troubleshooting and repair actually consist of. For starters, they could purge that word 'training' altogether, and leave 'training' to those who have puppy dogs in need of housebreaking.

Alternatively, CompTIA could just go away, and cease burdening working technicians with its demonstrably worthless 'training' and 'certification' programme.

- - -

Note:

[1] I don't mean to single out CompTIA here. All of the OEMs' 'training' adheres to the same witless orthodoxy, and is equally a waste of time and resources.

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FEEDBACK

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Friday, March 9, 2012

Lexmark T64X -- 500-Sheet Add-On Trays

There appears to be two versions of outfeed pinch roller tensioning in the T64X 500-sheet trays.

There's what I take to be an earlier version, where the tensioning method is the same as it was for preceeding T models. There's also a simplified version. This post explains the operation of the earlier type, and shows a modification to enhance its reliability. This post gives the teardown procedure for the trays.

In the simplified version, the drawer-actuated tensioning lever has been deleted. The pinch roller is always tensioned; there's no lever to jam and break.

We've seen several of the earlier T64X trays lately with broken tensioning levers. The fault is easy to spot -- the pinch roller (the smaller roller in front) has no tension against the outfeed roller at all; you can see daylight between the rollers. Here's a view inside of what's happened in those cases.

The lever has snapped. The spring has jumped off its hook on the lever. Pinch roller tensioning is completely inoperative -- the tray will not feed.

To fix this, first pry the lever remnant off from below with a long, slim-bladed screwdriver. Then get the loose end of the spring hooked over the lever's spindle and tensioning is restored. (Getting the spring end in place is easier said than done, but it is doable. You have to distort the loop at the end of the spring a bit to get it to fit over the spindle. Here's a view of a completed tensioning repair.

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FEEDBACK

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Thursday, March 8, 2012

HP LaserJet 2300 -- Add-On Tray Pickup Roller Access

Pickup Roller P/N is RB2-6304.

The roller is accessed from below. There are two plastic covers concealing the roller's swing-latch bearings. For a 500-sheet tray, proceed as follows (250-sheet is similar):

1) Tray Unit less tray upside down.

2) Front Sheet Metal Cross-Member
- Two M4x10mm bright washerhead threading screws.

3) Left Side Bearing Cover
- One claw at inboard rear corner.

4) Right Side Bearing Cover
- One claw at inboard centre.

5) Left Side Bearing
- Unlatch and remove it.

6) Right Side Bearing
- Unlatch and slide it rightward over the shaft.

Here's a view of the roller ready to be removed.

Don't forget to transfer the two slip rollers over to the new pickup roller.

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Monday, March 5, 2012

Lexmark T64X -- False 927.02 Errors

927.02 is a 'cartridge fan stalled' error. Its likeliest cause is an open 10 ohm resistor, R30.[1] Lexmark published a bulletin about this saying to replace the System PCA to solve the problem. Doing that certainly does solve the problem, but there's a cheaper way -- solder in a replacement resistor.

Here's a view of R30. It's near the upper front corner of the PCA.

R30 is at the centre of the photo. In the event of a 927.02 error, check R30 with an ohmmeter. It should read 10 ohms or very close to it. A very high reading is a certain indication that R30 is open.

There's no need to remove the defective surface-mount resistor, just solder a replacement conventional resistor in place across R30.

We didn't have any 10 ohm resistors on hand when I went to try this repair, so I had to use two 4.7 ohm resistors in series -- close enough. Here's a view of the completed repair after flux removal with flux solvent.

That board went back into a T644 with two add-on 500-sheet trays, and I ran quite a lot of paper through it with no recurrence of the error. All indications are that this is a sound, legitimate fix.

Soldering Technique

No special equipment is needed for this. I used an old Weller WTCPT soldering station with a TC201T iron and an 800° Fahrenheit tip, like so.

60/40 tin/lead solder works fine. There is one catch -- you have to have suitable liquid or paste flux[2] so you can apply flux prior to applying heat/solder. Here's how it's done:

a) Cut and shape a resistor's leads A/R to fit in place at the ends of the existing surface- mount resistor.

b) Apply flux to the area of the solder joints.

c) Hold the prepared resistor in place.

d) Load a bit of solder onto the soldering iron's clean tip and apply the solder-bearing tip to one connection point. The flux acts as a very effective heat-transfer medium. It takes only about one, maybe two seconds for the solder to flow and produce the effect seen in the second photo above. Repeat for the remaining connection point and you're done.

It's nice, but not essential, to clean away the flux residue with flux solvent. The residue from proper electronic solder flux is quite benign and will do no harm.

- - -

Notes:

[1] On the resistor it says "100". What that means is "10, with zero zeroes before the decimal point". By that notation, a 100 ohm resistor would be marked "101", 1,000 ohms "102" and so forth.

[2] I still have liquid flux left from my circuit board repair days. The stuff is still available, but it's sold by the gallon. It's Kester No. 1544, Kester P/N 63-0000-1544.

An alternative is Kester's 186 RMA Flux Pen, Kester P/N 83-1000-0186.

Don't use the common paste flux meant for soldering copper pipe. That stuff leaves a corrosive residue.

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Thursday, March 1, 2012

Oki 590/1 -- Ribbon Drive

An Oki 591 is in the shop with an inoperative ribbon drive. The wire projection at the top of the drive spindle is sheared away. Apart from that, the mechanism is working fine. Here's a view of the ruined spindle.

A replacement ribbon drive gear case is P/N 51228501. We don't have one in stock, and the customer would likely squawk about the price anyway, so I'll try replacing just the spindle with one from a salvaged gear case.

The ribbon drive gear case on a 590/1 incorporates an auto gap-setting mechanism. This one appears to be working ok, so this should work out alright.

The gear case has four claws holding it to the carriage. Unlike the 320/1 Turbo, this gear case is not entangled with the carriage cable, so it's quite easy to remove it in one piece with the carriage in place in the printer.

Carefully separate the two halves of the gear case, and you get to here.

The ribbon drive spindle should be the only item to remain with the upper half.

With none of the gears askew or in disarray, it's a straightforward job to replace the ribbon drive spindle and snap the gear case back together.

You have to check printhead gap and parallelism on reassembly. The manual calls for a 0.014" gap at gap setting '2'. That seems too small a gap to me; I set these printers to 0.016" at gap setting '2'. To manually obtain a desired gap setting, turn the adjustment screw gently as you move the carriage -- that gets the big auto-gap wheel to jump an increment. Repeat as needed to get to position '2'. With the correct position selected, the gap and parallelism adjustment procedure is no different from that for the 320/1 Turbo.

Anyway, this repair went nicely. Fortunately, the machine overall is in good shape, and all it needed was the ribbon drive spindle and some cleaning up. More often than not, these things are basket cases when they arrive here -- in need of a thorough overhaul, or the short journey to the big bin out back.

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Friday, February 10, 2012

Questions to Pose

The next time some CompTIA/PDI+ personage approaches you with a requirement to submit to their 'training'/testing/certification scheme, pose these questions to them: "Within the last 96 hours, how near have you been to a malfunctioning printer? Within a metre? Within a mile? Would you know a malfunctioning printer from grandma's wringer washing machine if one were to jump up behind you and bite your ass? What qualifies you to bestow or withhold a credential, a qualification? Where does that 'authority' come from?"

See what they say. I'd pay money for a ticket to watch.

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HP LaserJet 2300 -- Fuser Access

Proceed as follows:

1) Cartridge

2) Tray 2

3) Interface Connections Cover

4) Right Side Cover
- Under the cartridge door, there's a rectangular latch button. Push that down far enough and the cover can be slid forward about 5/16" to free it.

5) Rear Cover/Door
- Open the rear door part way. There's a pivoting guide rib array inside that can be unhooked to permit the door to drop open all the way.
- Two M4x10mm pan head threading screws.
- Two claws just inside the Tray 2 cavity.

6) Duplex Infeed Guide
- Two M4x14mm YZD pan head threading screws w/captive washers.
- Two small claws, left and right sides.

7) Fuser
- Three cable connections.
- One M4x10mm pan head threading screw.
- One M3x6mm pan head screw w/captive star washer.

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HP LaserJet 42X0/43X0 -- Tray 2 Won't Lift; Motors Don't Turn

The 4250/4350 machines have a sensor in the paper path that the 4200/4300 printers don't have. That sensor, if actuated at power on, produces a very odd symptom; there's no motor operation and Tray 2 doesn't lift, yet the machine ends up displaying 'READY'. The machine is completely inoperative in spite of the apparent 'READY' condition.

The sensor that can cause that to happen is PS109, Paper-Width Sensor #2. It's only present in the 4250/4350. Here's a view of where it resides.

(In the photograph, the registration assembly's flap is pulled back and held away.)

The sensor at the left is PS106, Paper-Width Sensor #1. The central sensor is PS103, the Top-of-Page Sensor. Way over to the right is PS109, Paper-Width Sensor #2. That's the one that can bring on the symptom.

We ran into the problem here right after one of the guys replaced a registration assembly in a 4250 -- no motor operation, no Tray 2 lift, yet the display said 'READY'.

It turned out that he'd installed a 4200/4300 registration assembly in a 4250. The 4200/4300 registration assembly's flap doesn't provide clearance for the additional sensor, so the sensor is always actuated. Here's a view of the two different registration assemblies.

Above is the 4250/4350 registration assembly P/N RM1-1098. Below is the 4200/4300 registration assembly P/N RM1-0011. Note the absence of a clearance punch-out for PS109 on the lower assembly's flap. That's what brought on the symptom.

It appears that HP has discontinued P/N RM1-0011, and is only supplying P/N RM-1098, the 4250/4350 style. That registration assembly will work in 4200/4300 machines as well as 4250/4350 machines. However, refurbishers are still supplying P/N RM1-0011, so those are still around to make the mistake with, which is exactly what happened here.

Needless to say, a shard of paper trapped under the registration assembly's flap at PS109 would bring on the same symptom. It must be a bug in the printers' firmware that's at the root of this; the printers ought to report a paper jam condition when a sensor is actuated at power on -- not come supposedly 'READY'.

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Tuesday, February 7, 2012

Lexmark T652 -- Bin Full Sensor

A T652n came in the shop with its bin full sensor flag missing. In configuration mode and diagnostics mode, you can 'continue' past the bin full error message to view page counts and the event log, and you can even print a test page in diagnostics mode. Aside from that, the machine is rendered inoperative until the sensor is either replaced or disabled.

Disabling the Sensor

Unplugging the sensor disables it. The message, "Remove paper from standard output bin" will go away and the machine can be used. The sensor's connector on the System PCA can be reached by way of the DIMM slot access panel under the left side cover. Proceed as follows:

1) Access Door
- Open it.

2) Access Panel
- Loosen off two M3x6mm slotted hex head screws (5.5mm A/F).
- Slide the panel forward to free it. It may take a bit of persuasion to get it to move.

3) Sensor Cable Connector
- It's at the extreme upper rear corner of the System PCA.

Replacing the Sensor

The complete sensor assembly is P/N 40X4372. The optical sensor portion only is P/N 40X4369. (That's unlikely ever to fail.) The flag can't be had on its own, you have to get the complete sensor.

The sensor is well tucked away under the top cover. There's no getting at it without removing that cover. Proceed as follows:

1) Cartridge

2) Tray 1

3) Redrive Cap

4) Back Door
- Disengage the support strap from its 'inverted T' slot and pull the door off its hinge pins.

5) Lower Rear Cover w/Fuser Access Door
- Two M3x10mm washerhead threading screws.
- Open the lower door.
- Two M3x6mm black washerhead screws.
- Open the fuser access door -- two claws.
- Tip the cover rearward and lift it off of two hook-points at the bottom.

6)Redrive Assembly
- Two M3x10mm washerhead threading screws.
- Two outward-hooking claws, left and right side, at about the middle.

7) Connection Access Cover
- Open it fully and its hinges can be popped free rearward.

8) Left Side Cover
- Two M3x8mm black washerhead threading screws in the handgrip wells.
- Two M3x10mm washerhead threading screws in deep wells in the side of the toner cartridge cavity.
- There are six claws, and one of them can be quite tenacious. First, pry at the angled upper front lip to free the upper two claws. The troublesome claw is located roughly 3" from the front and 3" from the bottom. You may have to reach in with a long narrow-bladed screwdriver to pry it loose.
- With all the claws freed, the cover comes away easily from its hinges.

9) Right Side Cover
- One M3x10mm washerhead threading screw at the rear.
- Two M3x8mm black washerhead threading screws in the handgrip wells.
- Two M3x10mm washerhead threading screws in shallow wells in the side of the toner cartridge cavity.
- This cover has an array of claws similar to the left side side cover's, but it comes off more easily.

10) Fuser Cleaning Wand Cover w/Wand

11) Top Cover
- One M4x10mm pan head threading screw at the right rear.
- Four M3x10mm washerhead threading screws.
- The front edge has to be forced up past the rear edge of the upper front door. NOTE: It's a bit difficult to get this cover levered back into place at the front, but it is doable without damaging anything.

12) Sensor
- One claw.
- One cable connection at the sensor
- NOTE: A new sensor comes with a cable. Should you choose to install the sensor with its new cable, you'll have to remove the System PCA's cover..

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Monday, February 6, 2012

Lexmark T652 -- Autocompensator Removal

The autocompensator in the T65X machines is similar to that in the earlier Ts, but there's been some rearrangement of items.

On the T650s, autocompensator removal and replacement are straightforward. On the T652s, there's a complication. There's an e-clip at the left side end of the pivot rod that's easy enough to remove, but it's near impossible to get back on because it's tucked away in a recess. This procedure clears away the item that interferes with access to the e-clip.

Proceed as follows:

1) Cartridge

2) Tray 1

3) Redrive Cap

4) Back Door
- Disengage the support strap from its 'inverted T' slot and pull the door off its hinge pins.

5) Lower Rear Cover w/Fuser Access Door
- Two M3x10mm washerhead threading screws.
- Open the lower door.
- Two M3x6mm black washerhead screws.
- Open the fuser access door -- two claws.
- Tip the cover rearward and lift it off of two hooks at the bottom.

6) Connection Access Cover
- Open it fully and its hinges can be popped free rearward.

7) Left Side Cover
- Two M3x8mm black washerhead screws in the handgrip wells.
- Two M3x10mm washerhead screws in deep wells in the side of the toner cartridge cavity.
- There are six claws, and one of them can be quite tenacious. First, pry at the angled upper front lip to free the upper two claws. The troublesome claw is located roughly 3" from the front and 3" from the bottom. You may have to reach in with a long narrow-bladed screwdriver to pry it loose.
- With all the claws freed, the cover comes away easily from its hinges.

8) Set the machine on its back.

9) PTO Shaft
- Pull it out.

10) Left Side Chassis Stand Block
- Two M5x12mm pan head screws. (The nut plates for these screws are unsecured once the screws are removed. 'Best to remove the nut plates as well.)
- Autoconnect connector. Two claws. Push it upward.
- Autosize sensing module cover. One claw at the inner rear.
- Autosize sensing cable -- disconnect it.

11) Retraction Spring
- Unhook it and remove it.

12) Motor End Cap
- Cut the ty-wrap and slip the cap off.

13) Three Cable Connections
- NOTE that the blue cable goes above; the white cable goes below.
- Unplug them. The motor's cable can't be entirely freed until the unit is dismounted.

14) One M3x8mm pan head screw w/captive washers
- At the rear of the autocompensator's frame -- remove it.

15) E-Clips
- Remove both from the autocompensator pivot rod.
- AT REASSEMBLY, install the left side clip first, then the right side clip.

16) Slide the unit leftward to free the pivot rod's right side end. The unit can come away. Free the motor's cable entirely.

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Lexmark T65X -- Autocompensator Gear Spindle Loss

A T652n came in the shop with a little bag taped to it containing a mystery part and a note, like so.

The printer worked from Tray 1, but the pickup cycles were growly. Turning the pickup rollers backwards by hand produced ratchety sounding clicks, as from gear teeth jumping.

It turned out that the mystery part was a gear spindle that had slipped out the side of the autocompensator arm. Here's a view of it.

There's a whole row of these spindles up the length of the arm. The loose one slid back into place easily, restoring normal 'feel' to the gear-train.

I dabbed both ends of each spindle with CA adhesive. (The uppermost spindle is a bit difficult to get at.)

This post tells how to get the autocompensator out of a T652.

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Tuesday, January 31, 2012

Oki 320/1 Turbo -- Paper Out Sensor Inoperative

There's a subtle defect that can befall a pull-up roller assembly. The defect will make the paper out sensor appear to be inoperative (always sensing paper present).

The defect involves the mylar strip across the rear of the pull-up roller assembly. That strip has a little protrusion to it just above the paper out sensor's actuator. If the strip gets shifted around on its rectangular mounting studs, the protrusion will constantly actuate the sensor.

Here's a view of a shifted strip/protrusion.

That mispositioned protrusion will displace the sensor's actuator whether paper is present or not. Paper won't load to its proper position, and the 'park' function will eject paper right off the tractors.

Here's how it's supposed to look.

Viewed from above, the shifted mylar strip appears to be more-or-less correctly in place. As I said earlier, it's a subtle defect.

The defect is easy to correct, and I added a drop of CA adhesive to the mylar strip's mounting studs to preclude it happening again.

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HP LaserJet 40X0 -- Tray 1 Pickup Assembly Replacement

Pickup roller and separation pad replacement are usually all the maintenance required on the tray 1 pickup assembly. It's possible for the solenoid to become sticky, resulting in mistimed extra pickup cycles. This post shows how to deal with that problem without having to replace anything. When you see the pickup roller hesitate as it's cycling, you know that its wrap-spring clutch is slipping. The clutch is an ultra-cheap one with plastic hubs; there's no servicing it, and service replacements can't be had. You have to replace the entire pickup assembly.

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The Tray 1 Pickup Assembly's P/N is RG5-2655. Proceed as follows:

1) Cartridge

2) Tray 2

3) Back Door
- Open it. It needn't be removed.

4) Rear Right Side Cover
- Tug it rearward to remove it.

5) Control Panel Overlay
- Pry at its right side lip to free two small claws.

6) Control Panel
- Pry up its front edge and two claws will let go. If the claws don't let go readily, you may need to coax them individually; they're down at either side near the front.
- One cable connection.

7) Top Cover
- Two M4x12mm bright pan head threading screws at the back.
- Two M4x12mm bright pan head threading screws under the toner cartridge access door.
- Cartridge engagement arm -- free its upper end.
- Pry at the right front to free the right front corner.
- Tug the front of the cover up forcefully to free it.

8) Front Right Side Cover
- One claw at the top.
- AT REINSTALLATION, MIND the on/off rocker's engagement with the switch linkage rod.

9) Left Side Cover
- One claw high up rear of centre.

10) Tray 1 Door
- Pry the inner platform's ways aside gently to free the platform.
- Slide the door rightward off its hinges.

11) Tray 1 Platform w/Sensor Arm Cover and Torsion Spring
- Torsion spring. (Not present on early machines. Later machines have a torsion spring associated with the right side hinge.) Free it from the underside of the platform.
- Tug forcefully on the sensor arm cover to pop it off the pickup shaft.

12) Two Black Extended-Head Screws near the Front
- The left side screw is visible by the violet cable for Tray 1's paper-out sensor.
- The right side screw is concealed under the envelope feeder's connector cover. Open the cover and you'll see the screw's head.

13) Tray 1 Pickup Assembly w/Left Side Cartridge Guide
- One in-line cable connection for the pickup solenoid.
- One cable connection for the paper-out sensor.
- Five M4x12mm black pan head threading screws in front. Four of them are in deep wells.

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Wednesday, January 25, 2012

Oki 320/1 Turbo -- Revision I0

A revision 'I0'[1] 320T is in the shop for a warranty repair. Oki has completely redesigned the printer's electronics in this revision. There's a switchmode power supply now, so the transformer is no more. Here's a view of the back of the printer.

The change lever position detection switches are now on their own little PCA tacked onto a bracket at the front of the power supply PCA, like so.

Part Numbers

Main Logic PCA: P/N 55117951 -- for revision I0. [TUESDAY, FEBRUARY 14, 2012 -- This may be in error. To be determined.][2]

Power Supply: P/N 55118051 -- for revisions E0, H0 and I0.

Main Logic PCA Replacement

When removing a PCA, the bracket around the interface option slot can remain in place -- just remove the one screw that's high up on the main logic PCA's bracket plus, of course, the two screws at the bottom of the PCA.

A replacement main logic PCA comes without the sheet metal bracket on it; the old one has to be transferred over. 'Easiest way to do that is as follows:

1) Remove wire bails and bracket from old PCA.

2) Remove wire bails from new PCA.

3) Install bracket and wire bails on new PCA.

4) Install two screws, adjust bracket position A/R and tighten screws. (The bracket has a slightly deranged position adjustment latitude. Get the USB connector opening centred and you'll have it right.)

When installing the PCA, jam a business card under the platen to hold the paper-out sensor actuated so its flag will be clear of the optical sensor on the PCA.

The lower rear end of the PCA sits in a sheet metal 'cradle', like so.

Cover Replacement

The wire bails and all the sheet metal make getting the top cover in position for closure a bit finicky. Relax and take your time. It's one of those chores that proves the truth of the saying, "haste makes waste".

Serial Interface Option

The old 'LXHI' serial I/F card won't work with this new revision. This post has information about the new serial I/F.

This Printer's Problem

The machine would come ready and load paper, but carriage motion was weak and halting. Eventually, it would stop with a 'spacing alarm' (ALARM flashing; HSD & PROP lit). The space motor felt fine. 'Likeliest culprit appeared to be the main logic PCA, and that turned out to be the case.

The New Technology

The following is from an Oki bulletin, Document #4096. (Pay attention; this is the sort of crap that will be on the test, for certain.)


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"What is SoC?

System-on-a-Chip or System on Chip (SoC or SOC) refers to integrating all components of a computer or other electronic system into a single integrated circuit (chip). It may contain digital, analog, mixed-signal, and often radio-frequency functions – all on a single chip substrate.

A typical SoC consists of:

One microcontroller, microprocessor or DSP core(s). Some SoCs – called multiprocessor System-on-Chip (MPSoC) – include more than one processor core.
Memory blocks including a selection of ROM, RAM, EEPROM and flash.
Timing sources including oscillators and phase-locked loops.
Peripherals including counter-timers, real-time timers and power-on reset generators.
External interfaces including industry standards such as USB, FireWire, Ethernet, USART, SPI.
Analog interfaces including ADCs and DACs.
Voltage regulators and power management circuits.

These blocks are connected by either a proprietary or industry-standard bus such as the AMBA bus from ARM. DMA controllers route data directly between external interfaces and memory, by-passing the processor core and thereby increasing the data throughput of the SoC.

In short, increasing chip integration helps to reduce manufacturing costs (due to fewer packages in the system) and to enable smaller systems. SoC designs usually consume less power and have a lower cost and higher reliability than the multi-chip systems that they replace."

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There you go. Aren't you glad you read all that? That's the sort of information that helps you fix printers, alright.

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Notes:

[1] That's 'eye zero'. Trust Oki to come up with the most ambiguous character combination possible for a revision level designation.

[2] MONDAY, FEBRUARY 27, 2012: Supposedly, the same PCA is used for both the 320T (narrow) and 321T (wide) models. The PCA as it's received has 321T functionality. If it's installed in a 320T, the 320T will think it's a wide carriage machine and act accordingly. Running the rolling ASCII self test will result in the carriage slamming into its right side stop.

When installed in a 320T, the 'Page Width' item in the Menu's rear, bottom and top feed groups must be set to 8" (the factory setting is 13.6").

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