Lexmark T-Series 500-Sheet Tray Teardown

This procedure gets you access to the electronics and the pinch roller drive/tensioning mechanism.

1) Upper Front Paper Guide
- One M3.5x8mm pan head threading screw.

2) Light-Coloured Upper Front Face (T64X Only)
- Four M3.5x8mm pan head threading screws from underneath.

3) Autocompensator Assembly
- NOTE the relationship of the paper out sensor flag to the actuating stud on the arm of the autocompensator. The stud goes under the curved ramp on the flag.
- Two cable connections.
- Three M3.5x8mm pan head threading screws.
- Unhook the retraction spring.
- Lift the item away.

4) Paper Out Sensor Flag
- Rotate it back a bit and it can be lifted out.

5) Electronics/Mechanism Box
- Two M3.5x8mm pan head threading screws at upper front and rear (not present on later units).
- Four M3x15mm pan head screws w/captive washer (T10 Torx recess).
- Two M3 nut plates.
- NOTE: At reassembly, don't bother putting back the two lower screws -- they're just a needless nuisance.
- Pass-Through Sensor -- dismount it and free its cable from its restraint slot.
- Two claws -- one high up in front; one low at the rear. The front one is easily accessible. Free the rear one by inserting a 1/4" slot screwdriver and rolling it to push the claw forward.
- The box is now free to be lifted out.

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FEEDBACK

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Lexmark T430 Fuser Replacement

You'll want to keep the toner cartridge access door closed while you're inserting a fuser. There's a linkage in the machine between the door and and a crank rod on the fuser. With the door closed, the linkage is sure to re-engage correctly when you put a fuser in.

Some of the screws involved are in fairly deep wells; you have to look for them.

1) Cartridge


2) Tray 1

3) Top Cover -- Loosen its Rear End
- Two M3x10mm washerhead threading screws; the two highest screws at the rear. (They're in deep wells.)

3) Left Side Cover
- Two finger-operable claws at the front.
- Swing the cover out enough that you can move it rearward to unhook it at the back.

4) Right Side Cover
- One M3x10mm washerhead threading screw under the toner cartridge access door.
- One M3x10mm washerhead threading screw in a deep well at the upper rear.
- One claw at the front by the tray 1 opening.

5) Rear Cover/Door Assembly
- One in-line cable connection at the left side, lower rear.
- Three M3x10mm washerhead threading screws.
- NOTE that one of the screws is very low down by the tray 1 cavity at the right.

6) Fuser
- Toner cartridge access door closed.
- AC power cable -- unplug it and free it from its hook-restraint.
- Exit sensor cable (three-conductor).
- Thermistor cable (two-conductor).
- Four M3x10mm washerhead threading screws -- two are high up and easily seen; the two lower ones are quite far forward inside the machine.
- Pull the fuser out the rear of the machine.

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FEEDBACK

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Lexmark T-Series Tray 1 Pickup Roller Replacement

See this post for information on service replacement rollers.

Remove Tray 1 and you have access to the pickup rollers. It's helpful to have the machine positioned so that its front is hanging out over the work surface a few inches.

The rollers are each held in place by a small claw at the end of the axle. Flex the claws inward slightly to allow the rollers to be slid off the ends of the axle. You will encounter the odd roller that won't slide off easily. Be careful not to overflex the claw when this happens, the claws are easily snapped off. Just flex the claw enough that it's not restraining the roller, and apply force as required to get the roller off the axle. The redesigned rollers (40X4308) limit the amount of claw flexure that's possible. It's only the early rollers (40X0070) that present this problem.

When installing or reinstalling early rollers, note and observe the directionality arrows on the hub. The new rollers have no directionality to them.

You may encounter an early roller that's been glued to its axle because its retaining claw got snapped off. In such a case, the only way to renew the roller will be to remove and replace the roller's tire in situ. Extra care must be taken to ensure that the tire's directionality is kept correct.

Whenever you're inspecting pickup rollers, check the action of their axle's one-way clutch as well. The axle should turn freely in the direction of paper feed. It should lock up when turned in the opposite direction. A defective clutch calls for replacement of the complete autocompensator assembly.

Lexmark 241 Errors

A 241 error indicates that paper failed to leave Tray 1 and reach the registration sensor after a pickup cycle was executed. Following are some likely causes:

a) Worn early-style pickup rollers with insufficient traction. See this post for information on the new-style service replacement pickup rollers.

b) Toner/paper-dust fouling the pickup rollers. Scrubbing the rollers' tires with a tooth brush and methyl hydrate may clear it up, but when machines get that filthy, they're usually due for a proper overhaul in the shop.

If the rollers are ok but you're getting solid, not intermittent, 241 errors, there's likely an outright hardware failure causing it. We've seen two such in our shop:

1) Failure of the auto-compensator to lower down onto the paper stack.

On the upper right side ledge of Tray 1, about half way back, there's a vertical protrusion that causes the auto-compensator to drop when the tray is pushed in. If that protrusion gets snapped off, the auto-compensator will remain in its retracted 'up' position, spinning its wheels in the air to no effect. Replace the tray.

2) Failure of the one-way clutch in the pickup rollers' axle.

If you take the tray out and try to rotate the pickup rollers by hand, they're supposed to turn freely in the direction of paper feed, but lock up in the opposite direction. If they turn freely in either direction, the axle/clutch has a defect. Replace the auto-compensator assembly.

In closing, I should point out that whenever you're getting 241 errors, it can be helpful to get a look at what's happening as the machine is attempting to execute a pickup cycle. If you remove the redrive assembly from the rear of the machine, you're afforded quite a good view inside the tray. Both of the hardware failures described immediately above became obvious when I got a look inside that way. Unfortunately, the add-on trays don't permit such a view, short of sawing off their rear covering.

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Lexmark T64X Fuser Teardown/Overhaul

[NOTE: There's a condensed 'checklist' version of this document here.]

Proceed as follows:

1) Left Side Lamp Terminal Cover
- Two M3x6mm pan head screws.
- One rearward-gripping claw.

2) Left Side Lamp Terminal

NOTE 1: The screw w/captive washer at the electrical connection is sometimes extremely tight, and the plastic will break nearby before the screw breaks loose. To prevent this from happening, grasp the plastic on either side of the screw head with slip-joint pliers, and support it as you torque the screw to loosen it.

- One M3x6mm pan head screw at plastic base.
- One M3x5mm screw w/captive washer at electrical connection.

NOTE 2: Scrape the lamp contact's surfaces where it contacts the lamp terminal with a small screwdriver. The contact surfaces must be clean and bright. Contacts that show evidence of arcing and can't be easily made clean and bright must be replaced.

3) Lamp
- Only handle the lamp with a paper towel around it; the lamp's surface should not be touched. If a lamp does get anything oily on it, clean it w/methyl hydrate.
- Burnish the lamp's contacts with synthetic steel wool. Pitted contacts that cannot be made clean and bright call for replacement of the lamp.

4) Thermistor Cable
- Unplug it and free it from its restraints.

5) AC Spade Connector at the upper right of the top cover
- Disconnect and clean up any oily residue there.

6) Top Cover
- Two M3x6mm pan head screws.
- Check that the thermal fuse's screws are snug.

7) Stripper Bar Torsion Springs

8) Exit Roller
- Two self-latching bearings.
- NOTE that the flanged gear must mesh with the idler gear; the flange is the idler gear’s retainer.

9) Idler Gear

10) Pressure Roller Springs
- Unhook them at the lower front of the frame.

11) Ring Gear
- One external snap-ring.

12) Left Side Bearing^[1]

13) Hot Roller w/Bushings^[1]

14) Right Side Bearing^[1]

15) Input Ramp
- Spread the sides of the frame A/R to free it.

16) Stripper Bar
- Spread the sides of the frame A/R to free it.

17) Pressure Roller w/Bearings and Bearing Holders^[2]
- NOTE: Any evidence of flat-spotting or delamination is cause to replace this roller. A flat-spot will cause a thumping noise; delamination will only get worse.

- - -

At this point, you can proceed in either of two ways.

a) Carry on with the full procedure for a thorough overhaul.

b) Abbreviate the procedure for a 'good-enough' overhaul.
- Scrape the right side lamp contact.
- Blow out the lamp contact and the sensors w/compressed air.
- Apply a couple of drops of light mineral oil to the pressure roller arms' pivot points.
- Reassemble w/new parts A/R.

- - -

18) Output Ramp
- Two sensor cable connections.
- Spread the sides of the frame A/R to free it.
- Examine the sensor toggles. They must move freely and return to their upright positions smartly. Any tendency for them to bind or stick will result in paper jam errors

19) Pressure Roller Springs

20) Right Side Pressure Roller Arm^[3]
- One E-Clip.

21) Left Side Pressure Roller Arm and Link^[3]
- One E-Clip.

NOTE: The following three steps complete the tear-down, but for reasonably clean units they can be dispensed with. Only proceed with them for units with dirty frames that need to be washed. Whether you remove it or not, examine and scrape the right side lamp contact as was done for the left side contact.

22) Right Side Lamp Contact Assembly
- Two M3x6mm pan head screws.
- One bulkhead connector.

23) PCA
- Solenoid cable connection.
- Two M3x6mm pan head screws.

24) Solenoid
- One M3x6mm pan head screw.


26) Reassemble w/new parts A/R

- - -

Notes

[1] Re Hot Roller and bearings:

Hot rollers can look pretty bad but still work fine. That said, any hot roller that's not in perfect condition should be replaced for longest service life of the fuser.

Bearings that turn freely but with a slight feel of grease resistance to them are ok to re-use. Bearings that spin very freely are likely grease-starved and should be replaced. If at all in doubt, replace the bearings. As with the pressure roller bearings, there's really no way to judge life expectancy.

[2] Re pressure roller and bearings:

Rusty looking spindle ends indicate that the roller has been turning in seizing or seized bearings. Both the roller and its bearings must be replaced, even if the roller looks fine otherwise.

Bearings that turn smoothly and exhibit a bit of grease seepage are ok to re-use, but there's really no way to judge bearing life expectancy. These bearings are fairly heavily loaded for their size. Unconditional replacement is probably the best practice.

Some T64X fusers do not use plastic holders for the pressure roller bearings; the arms have been redesigned to accept the bearings directly -- a later design change, presumably.

[3] Re Pressure Roller Arm Pivots

The grease applied at the factory does not age well. It turns to a stiff sludge that interferes with the arms' freedom to pivot as they should. It takes lacquer thinner and a small brass-bristled brush to get the pivots clean.

Grease the pivots and the ends of the solenoid link at reassembly. The grease we use is Lubriplate No. 930-AA.

- - -

Frequently Replaced Parts

Assembly, 115V Fuser, T64X: P/N 40X2592

Bearing, Hot Roll [6003Z: 17mm bore x 35mm O.D. x 10mm thick]: P/N 99A0143

Bearing, Pressure Roller [R3Z: 0.1875" bore x 0.500" O.D. x 0.196" thick]: P/N 99A1621

Pressure Roller, 28mm dia: P/N LPR-T640

Coated (Hot) Roller, 30mm dia: P/N UFR-T640

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FEEDBACK

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Auto Paper Size Sensing

The cassette trays, both integral and add-on, all have auto size sensing. It's based on sensing the position of the tray's backstop. The backstop is attached to a sliding key inside the left wall of the tray. That key's position determines the combination of three plastic 'fingers' that protrude from the left side of the tray. Here's a view of them.^[1]



Pictured is the letter size setting -- the two lower fingers protrude, the upper finger is retracted. Those fingers act on leaf-spring actuators in the tray's cavity, pictured in the following photograph.



The actuators, in turn, act on three small snap-action switches on a circuit board (printed circuit assembly -- PCA) that's in behind the System PCA. Here's a view of the size sensing PCA in a T640 that's had its system PCA removed. (All the earlier Ts and the old Optra S are much the same.)



And here's a component-side view of the PCA itself.



At the right side are the three little pushbutton switches that inform the system PCA of the tray's size setting.

The switches tend to get flaky after long service, and size sensing becomes erratic; e.g. if the second switch up doesn't make when actuated, the machine will sense A5 size instead of letter size. It's easy to check the switches thanks to the paper size reporting feature in the Paper Menu. When you're viewing a tray's size on the display, you're seeing the actual size being sensed. If you remove a tray that's set for letter size and push on only the bottom actuator, the display's size reading should change to A5. To check for flaky size sensing, simply pull the tray out a bit and shove it back in several times slowly. If you even once see the size reading change from what it should be, you know you have sensing switch trouble. I've been able to get switches working by taking out the size sensing PCA and soaking the switches with WD-40. Then I've actuated them many times, dried off the PCA and reinstalled it. I don't know how long the effect of that treatment lasts.

There is a work-around for a machine with flaky size sensing, and that is to disable the size sensing feature. Invoke the CONFIG MENU. Scroll down to the item 'SIZE SENSING' and select it. There, you'll be able to change the size sensing from 'Auto' to 'Off'. With that done, when you go to the user's 'Paper Menu', you'll be able to specify the size for the tray and it won't matter that the size sensing is faulty.

- - -

[1] From the Optra S through the T640, the fingers are the same. So, any scrapped machine of those models is a source of replacements for damaged ones.

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Lexmark T64X Routine Teardown/Overhaul

[NOTE: There's a condensed 'checklist' version of this document here.]

Following is our standard procedure for an in-shop overhaul of a T64X series printer. The procedure assumes a machine that's basically in working order, but in need of a teardown, a thorough cleaning and a fuser overhaul.

The developer drive, main drive and the paper alignment assembly are left undisturbed; they normally don't require attention. In cases of severe toner spillage, those items do need to be removed and cleaned/overhauled.

PRELIMINARIES:

1) Auto Size Sensing; Tray Bias Roller
- See this post for information on checking and servicing the auto size sensing feature.
- Inspect the tray bias roller that's just inside the tray cavity at the right side. The roller must be free spinning and have no flat spots. Flat-spotted rollers must be replaced. The part is accessible once the right side cover has been removed. See this post for more information.

2) Maintenance Count
- To view the accumulated page count since the last time anyone cleared it, press and hold the 'check mark' and 'right arrow' keys while powering on. That invokes the CONFIG MENU where you can check and clear the maintenance count. Clear the maintenance count after you're done testing the completed machine.

3) Page Count
- The page count and the permanent page count can both be found in the DIAGNOSTICS menu within PRINTER SETUP. To invoke the DIAGNOSTICS menu, press and hold the 'down arrow' and the 'right arrow' keys while powering on.

4) Event Log
- The event log is an item in the DIAGNOSTICS menu.
- An empty event log is likely due to early firmware. A machine that's been taken off-site and brought to the shop is unlikely to have had no error events. A firmware update is in order whenever you see an empty event log.
- When there are items in the event log, note what they are. They're usually just paper jams and the like. The presence of printhead errors calls for printhead replacement. The machine is likely to be written off because of the high cost of the part.
- Clear the event log after you're done testing the completed machine.

ORDER OF WORK:

1) Toner Cartridge
- Machines seldom come into the shop with a toner cartridge. When they do, be sure to note it and label the cartridge so it goes out with the printer. If the cartridge has a defect, it should still go out with the printer, but clearly labelled that it's defective.

2) Paper Tray (Tray 1)
- Check that the backstop is linked to the size sensing key and is operable. When set for letter size paper, the two lower sensing fingers should protrude, the upper finger should be retracted.
- The four black ramps in front must be clean. Trays that have been used for sheets of labels are liable to have label adhesive muck fouling the ramps. Clean A/R with Varsol and/or methyl hydrate.
- Examine the pass-thru slot at the front of the tray for stuck labels or damage.

3) Redrive Cap
- Lift it up at its right side end to remove it.

4) Fuser Cleaning Wand Cover
- See this post regarding a defect in this item.

5) Fuser Cleaning Wand
- NOTE that the felt strip is removeable and reversible.
- In place of a cleaning wand, there is often an item that's just a cover for the cleaning wand cavity. It will have a small handle at the centre. The handle goes to the rear.
- You may encounter a cleaning wand or a cleaning wand cavity cover that has three protrusions on top that are meant to be gripped by claws on the underside of the cleaning wand cover. One or more of the claws are likely to have broken off -- the heat gets to them. We don't bother replacing covers with broken claws, they're a pretty useless feature, really. But should you encounter a user who insists on having a fully intact cover, the part number for a new cleaning wand cover is 40X0001.

6) Paper Support
- Tip it up and pull it off its hinges.

7) Back Door
- Open it to about 30º from vertical and you can pull it away off its hinges.
- Check that the duplexing deflector's torsion spring is in place and correctly hooked at its ends. The deflector must pivot freely, and return smartly to its at-rest position when released.

8) Redrive Assembly
- Two M4x8mm pan head thread-rolling screws.
- Two outward-hooking claws, left and right side, high up.
- Check that the output diverter is in place in its bearings and spring-loaded.
- Check that the duplex diverter push-rod is properly fastened and free moving. If the little fasteners/glides show any sign of being loose, apply a drop of CA adhesive to cement them in place permanently.

9) Left Side Cover
- Two finger-operable claws at the front. Swing it open far enough and its upper hinge will pop apart harmlessly for removal.

10) Right Side Cover
- One M3x22mm washerhead threading screw from high up inside the redrive cavity (M3x10mm on the T642 and T644).
- One M3x10mm washerhead threading screw from inside the cartridge cavity.
- One claw at the front just above the MP Feeder.

11) MP Feeder Door/Platform
- Open it to about a 45º angle and it can be pulled off its flatted hinge pins.
- If this item is really filthy, it can be easily dismantled for washing. There are just the three obvious m3x8mm pan head threading screws holding it together.

12) Fuser
- Power cable in-line connection.
- Signal cable connection at PCA.
- Two M4x8mm pan head screws w/captive washers.

13) Power Supply
- One M3x6mm pan head screw at the black plastic connector access cover.
- Connector access cover -- it can dangle from the cable that’s strung through it.
- Two M3x6mm pan head screws.
- Unplug the large connector. If the locking tab is obstinate, use Channelocks to squeeze it open, while gently prying at either side to free the connector.
- The power supply slides out the right side until you can disconnect the fuser power cable and slide it out completely.
- NOTE: The early power supply design really fills up the space available for it. It can tend to hang up and be a bit difficult to slide out. Jiggle it A/R to coax it out. There's a later design that's much less bulky.

14) Control Panel Cover & Window
- Two M2x8mm washerhead screws from in behind (they're No. 1 Phillips recess).
- Tug forcefully at the upper rear lip and the cover will come away.
- The window is free to be removed once the cover is off.

15) Top Cover
WARNING: Unlike earlier models, once the top cover has been removed from a T640 there’s nothing to stop the toner cartridge access door frame from coming free of its hinges. If you mean to set the machine on its back, be certain the door is closed and latched first so it can’t come free with possibly damaging results.
NOTE: At the upper right rear corner there may be a screw w/captive washer. It need not be removed. The tab it’s associated with is not actually fastened in place by the screw.
- One M3x10mm washerhead threading screw at the right side -- it’s a bit tucked away below the rearward curve of the cover.
- Three M3.5x12mm threading screws w/captive oversize flat washer.
- Close the toner cartridge access door.
- Yank the cover up at the front and force it up past the upper lip of the toner cartridge access door. It’s then free to be worked clear of the bin-full sensor toggle.)

16) System PCA Enclosure Cover
- Loosen off six M3x6mm pan head screws.
- Slide the cover forward slightly and pull it away over the screwheads.

17) PTO Cover
- One M3x8mm washerhead threading screw.

18) 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.
- Check for any accumulation of label adhesive muck on the item's undersurface. Clean with Varsol and/or methyl hydrate A/R.
- 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.

19) MP Feeder Pick Roll
- One claw. Don't over-deflect it. It's easily snapped off. In the event of a claw snapping off, a small (3") ty-wrap works fine as a retainer.
- Blow off the paper dust and clean the tire with lacquer thinner.

20) MP Feeder Lower Deflector/Elevator Flap Assembly
- NOTE 1: This item is easily removed, but can be awkward to get back in place. Before proceeding, note carefully the relationship between the MP Feeder’s pickup cycle cam, and the cam follower that’s integral with the Elevator Flap. Keeping that relationship in mind at reassembly will be helpful.
- NOTE 2: At reinstallation, wipe off the face of the separation pad with methyl hydrate prior to putting the pickup roller back on its shaft.
- One M3x10mm washerhead threading screw at the solenoid's base.
- Two M3x12mm washerhead threading screws at the right side.
- Two M3x10mm washerhead threading screws at the left side.
- Flap Spring. NOTE that the bottom end of the spring must be seated correctly in its channel so that it will contact the steel frame of the paper feed alignment assembly. It’s the ground continuity contact for the elevator flap.
- Optical Sensor -- unhook it and let it dangle.

21) Pick Rolls
- If early-style pick rolls (40X0070) are in place, the retaining claws can easily be deflected too far and snapped off. Later-style pick rolls (40X4308) were redesigned to preclude that happening.
- If reinstalling early-style pick rolls, note the arrows on the hubs indicating direction of rotation. Only the later-style pick rolls should be used as service replacements. See this post for more information.
- Check the operation of the one-way clutch that's integral with the pick roll axle. It should turn freely in the feed direction; lock in the opposite direction.

22) Inner Deflector
- Two tabs at lower front, left and right.
- Two upward-hooking claws near the upper rear; accessible through rectangular openings.)

23) Transfer Roller
- Pry up at its left side bearing to free it.
- Handle the roller with a paper towel. Avoid touching the roller's surface.
- NOTE that the gear goes to the right side.
- Blow off any toner. The shaft ends that ride in the bearings should be immaculately clean. Use Varsol and/or methyl hydrate sparingly to clean them.

24) Charge Roller Assembly
- Handle the assembly with a paper towel. Avoid touching the rollers' surfaces.
- Clean only by blowing off.
- It's all but impossible to judge a charge roller's fitness for service by its appearance. Only a print test will show if it's satisfactory.

25) Post-Transfer Paper Deck
- Two outward-hooking claws underneath at front left and right.
- One M3x8mm washerhead threading screw at the ground wire terminal.

26) Blow out Chassis. Blow out four optical sensors.

27) Printhead
- Inspect the printhead's output 'window' for dust or debris. A flashlight and a mirror from a lady's makeup compact are helpful. It's sometimes possible to blow off the window by flexing the 'straw' of a duster can to point up at it. If that doesn't work, unfasten the printhead and flip it over to clean the window thoroughly. NOTE the following before loosening any screws:
- There are three screws to be removed. There's a fourth screw daubed with red varnish that shouldn't be disturbed.
- At the screw at the right front, take a sharp HB pencil and trace the perimeter of the screw's captive washer so as not to lose the factory-set position of the printhead.
- Three M3.5x12mm pan head threading screws w/oversize captive flat washers.

28) Paper Feed Alignment Gearing and Drum Drive Gear -- inspect and clean gear teeth A/R.

29) MP Feeder Pickup Clutch -- lubricate sparingly with WD-40.
- Apply the WD-40 at each end of the clutch's control collar so it can wick down into the clutch spring.

30) PTO Vertical Shaft -- pack grease around its two bearings.

31) Transfer Roller Bearings
- Clean these with a Q-Tip and Varsol followed by methyl hydrate.
- The bronze bearing especially should be immaculately clean. No lubricant of any kind is to be applied to it or to the plastic bearing at the left side.

32) Reassemble the machine back through item '13)', the power supply. Install the MP Feeder Door/Platform, the left and right side covers and the paper support.

33) Wipe the paper tray's slide ledges with WD-40. Fill it with paper and install it in the printer.

34) Install the cartridge. Set the machine aside.

35) Overhaul the fuser per the procedure.

36) Complete the reassembly of the machine.
- Fuser.
- Redrive Assembly.
- Back Door.
- Fuser Cleaning Wand.
- Fuser Cleaning Wand Cover.
- Redrive Cap.

37) Test operability.

38) Clear the error log.

39) Clear the maintenance count.

40) Remove paper from tray 1.

41) Remove the cartridge if it doesn't belong to the machine.

42) Install a bubble-pack restraint under the charge roller.

43) Tape the front of the machine shut.

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FEEDBACK

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