The Passing of Tom Gaspick

Tom Gaspick sadly passed away today in the early AM of January 14th after a short battle with Cancer. 

He will be missed and remembered by all those who loved him and all those he touched with his writing. 

Details of his funeral will be posted here when available. 

End Of The Line

Today was my last day of employment at the bricks-and-mortar repair shop where I got the content for this virtual repair shop. The work had been drying up for a long time, so my layoff comes as no surprise.

My thanks to those who've written favourable comments. I'm glad to know that I've been of some help.

I'll leave this blog up for the time being. It's extremely unlikely that I'll ever see any printer work again, so new material is probably at an end.

Anyway, if anyone has technical documentation work to be done, I'm available.

Regards to all,

Tom

Oki 395 -- Power Supply Replacement -- Revision 'A' and 'B' Printers

[The revision level of early printers is given by the fourth character of the serial number.]


Direct replacement power supplies for revision 'A' and 'B' printers are no longer available; you'll have to use the power supply meant for revision 'C' machines. ( P/N 42312551.) That power supply has different cable connectors than those on earlier power supplies. There are two ways to deal with that wrinkle.


a) Replace the affected cables:

You'll need to order one each of P/N 41998701 (9 conductor cable) and P/N 41998801 (13 conductor cable). Those cables will fit the connectors on a revision 'C' power supply.

Or,

b) Swap the old power supply's connectors over to the new power supply.

The circuit boards are of simple, single-sided construction. It's not difficult to unsolder the connectors, and install the early-style connectors on the new power supply.

The new-style connectors don't take heat very well, and are likely to be ruined by removing them, but that's really not a problem since they won't be needed again anyway. Fortunately, the early-style connectors stand up to unsoldering and resoldering just fine.

- - -

To gain access to the power supply, proceed as follows:


1) Platen Knob

2) Ribbon Access Cover

3) Top Cover
- Two M4x10mm bright pan head screws w/captive plastic washers at the rear.
- Tip up the rear of the cover and unhook its lower front edge.
- NOTE: There are two M4 hex nuts in pockets at the rear of the machine that are unsecured once the cover has been removed. It's best to remove them and set them aside with the two cover screws. The nuts are easily dislodged and lost if compressed air is used to clean the chassis.
-RE-INSTALLATION NOTE: Mind the bail actuator when re-installing the cover. The actuator must be fully toward the rear of the printer, so it ends up behind the bail's left side arm.

4) Ribbon Cartridge

5) Control Panel w/Sheet Metal Mount
- One ZIF connector for the flat cable.
- One two-conductor cable connection at the lower right of the main logic PCA (CN13).
- Five M3x6mm washerhead screws.
- Lift away the assembly a couple of inches and disconnect one four-conductor cable (CN11).

6) Main Logic PCA
- Nine cable connections.
- One captive M4 screw securing a bracket at the lower rear of the PCA.
- NOTE: Connections CN1 and CN11 are physically identical. In later machines, CN1 is yellow to avoid mix ups. In early machines, CN1 and CN11 are both white. If you encounter a white CN1, mark the CN1 cable end so you won't transpose it with CN11.

7) Mechanism
- Two cable connections at the upper right of the interface connection PCA.
- Three M4x8mm pan head screws w/captive washers at the upper rear.
- Three M4x12mm pan head screws w/captive washers; three anchor plates low in the chassis pan.
- Lift the mechanism straight up out of the chassis pan.

8) Power Supply
- Four M4x8mm pan head screws w/captive washers.

9) Cabling

Should you have chosen to replace the cables, they're now accessible -- you just have to coax out the plastic covering pieces.

Before disturbing the old cables, take a Sharpie marker and make a reference mark on the chassis pan near the power supply end of the cables. Mark the edges of the cables correspondingly adjacent to the chassis pan mark. Once you have the old cables out of the chassis pan, use their marks to guide you in marking the new cables the same way. Then you'll be able to get the new cables in place with just the right amount of slack at the power supply end.

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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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FEEDBACK

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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.

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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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FEEDBACK

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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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FEEDBACK

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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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FEEDBACK

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