HP LJ 4350tn -- Paper Feed Assembly Access

1) Cartridge

2) Tray 2

3) Back Door Open

4) Top Rear Cover
> Pull it straight up.

5) Right Side Rear Cover
> Pull it straight back.

6) Cartridge Engagement Arm
> Disconnect it from the toner cartridge access door.

7) Top Cover Assembly
> Four M3x8mm washerhead screws.
> Lift the cover about an inch.
> Control panel cable connection.
> Lift the cover away entirely.

8) Formatter Cage Door
> Open it and lift to remove.

9) Right Side Cover
> One large claw at upper rear.
> One claw at arrowhead in front behind tray 1 door.
> One claw at arrowhead in front just below tray 1 door.
> MIND THE SWITCH LINK'S ENGAGEMENT when reinstalling this cover.

10) Left Side Cover
> One claw at upper centre.
> One claw at arrowhead in front behind tray 1 door.

11) Tray 1 Door
> Spread the platform ways to separate the door from the platform. The door slides rightward off its hinge pins.

12) Tray 1 Platform w/Torsion Spring
> Free the upper end of the torsion spring. Lower the platform.
> Tug on the paper-out sensor's cowl to free it.
> Lower the platform to where it will slip off its left side hinge pin.

13) Wire Bail Over Fan
> Pry it free of its restraint hooks at its rear.

14) Door-Open Switch Cable Connection at J95
> Free the two-conductor cable from its trough. You may have to deal with some cable entanglement.

15) Front Right Side Cover w/Cover-Open Switch
> Three M3x12mm washerhead screws.
> One claw near the right side end of the envelope feeder slot.
> There's one stiff downward-gripping claw low down in back, accessible through a rectangular opening in the steel frame. Pry it upwards to free it.

16) Tray 1 Pickup Solenoid Cable Connection at J79
> Free the two-conductor cable from its trough. You may have to deal with some cable entanglement.

17) Tray 1 Pickup Assembly
> Envelope feeder slot cover.
> Paper-out sensor cable connection at left side.
> Two M3x8mm washerhead screws at the left side.
> Two M4x16mm pan head threading screws, left and right, low down in deep wells.
> Two M4x10mm pan head threading screws, left and right, near the ends of the envelope feeder slot.
> The item is free to come away. Mind the solenoid's cable as you remove it.

18) Paper Feed Clutch Cable Connection at J89
> Free the two-conductor cable from its trough. You may have to deal with some cable entanglement.
> Open three cable clamps.
> Pull the cable through the rectangular grommet.

19) Paper Feed Assembly
> One M3x8mm washerhead screw at its left side end.
> Two M4x10mm pan head threading screws at its upper mounting holes.

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HP LJ 4350tn -- Tray 1 Pickup Assembly Removal

1) Cartridge

2) Tray 2

3) Back Door Open

4) Top Rear Cover
> Pull it straight up.

5) Right Side Rear Cover
> Pull it straight back.

6) Cartridge Engagement Arm
> Disconnect it from the toner cartridge access door.

7) Top Cover Assembly
> Four M3x8mm washerhead screws.
> Lift the cover about an inch.
> Control panel cable connection.
> Lift the cover away entirely.

8) Formatter Cage Door
> Open it and lift to remove.

9) Right Side Cover
> One large claw at upper rear.
> One claw at arrowhead in front behind tray 1 door.
> One claw at arrowhead in front just below tray 1 door.
> MIND THE SWITCH LINK'S ENGAGEMENT when reinstalling this cover.

10) Left Side Cover
> One claw at upper centre.
> One claw at arrowhead in front behind tray 1 door.

11) Tray 1 Door
> Spread the platform ways to separate the door from the platform. The door slides rightward off its hinge pins.

12) Tray 1 Platform w/Torsion Spring
> Free the upper end of the torsion spring. Lower the platform.
> Tug on the paper-out sensor's cowl to free it.
> Lower the platform to where it will slip off its left side hinge pin.

13) Wire Bail Over Fan
> Pry it free of its restraint hooks at its rear.

14) Door-Open Switch Cable Connection at J95
> Free the two-conductor cable from its trough. You may have to deal with some cable entanglement.

15) Front Right Side Cover w/Cover-Open Switch
> Three M3x12mm washerhead screws.
> One claw near the right side end of the envelope feeder slot.
> There's one stiff downward-gripping claw low down in back, accessible through a rectangular opening in the steel frame. Pry it upwards to free it.

16) Tray 1 Pickup Solenoid Cable Connection at J79
> Free the two-conductor cable from its trough. You may have to deal with some cable entanglement.

17) Tray 1 Pickup Assembly
> Envelope feeder slot cover.
> Paper-out sensor cable connection at left side.
> Two M3x8mm washerhead screws at the left side.
> Two M4x16mm pan head threading screws, left and right, low down in deep wells.
> Two M4x10mm pan head threading screws, left and right, near the ends of the envelope feeder slot.
> The item is free to come away. Mind the solenoid's cable as you remove it.

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HP LJ 4350tn -- DC Controller PCA Access

The DC Controller PCA includes a hard-wired paddle PCA for the formatter connection. The paddle PCA is permanently connected to the DC Controller by a flat cable and two wires. The combination makes for a lot of fiddling about with cabling to replace a DC Controller. Take great care not to damage the broad flat cable.

1) Back Door Open

2) Top Rear Cover
> Pull it straight up.

3) Right Side Rear Cover
> Pull it straight back.

4) Cartridge Engagement Arm
> Disconnect it from the toner cartridge access door.

5) Top Cover Assembly
> Four M3x8mm washerhead screws.
> Lift the cover about an inch.
> Control panel cable connection.
> Lift the cover away entirely.

6) Formatter Cage Door
> Open it and lift to remove.

7) Right Side Cover
> One large claw at upper rear.
> One claw at arrowhead in front behind tray 1 door.
> One claw at arrowhead in front just below tray 1 door.
> MIND THE SWITCH LINK'S ENGAGEMENT when reinstalling this cover.

8) Formatter Cage
> Two M3x6mm bright washerhead screws at the rear.
> Pull it back to disconnect/remove it.

9) Formatter Connector Paddle PCA
> Remove two M3x6mm shoulder screws.

10) DC Controller PCA
> NOTE that connector locations J76 and J94 are not used.
> Two flat cables.
> Power supply cable -- squeeze the latch to disconnect it.
> Twenty remaining cable connections.
> Free the cabling from the trough A/R to free the blue and yellow wires going to the paddle PCA.
> Free the paddle PCA's flat cable from its trough.
> You may have to disconnect the Tray 2 size sensor's cable at the sensor's switch-block to fully free the paddle PCA's wiring. CAUTION: It's very easy to dislodge the switch-block when you're reconnecting the cable.
> Two M3x8mm washerhead screws.

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Hogwash

I had occasion recently to look up the fatal alarm indications in Fujitsu's DL6400/6600 maintenance manual; found them easily enough. On page 3-7 there's Table 3.5 - Fatal error alarm list. The table gives the names of the thirteen possible errors, and a brief description of each. The LED display codes are on Table 3.6 on the following page.

The alarm list table has a column titled "Recovery method". The first entry in that column, for the Power Alarm, reads "+40V supply has dropped". [?!]

Excuse me, but that's not a 'recovery method'. Of the thirteen alarms, ranging from 'left end sensor' to 'cut sheet feeder motor', eleven of them effectively indicate that "+40V supply has dropped" is the 'recovery method'. Needless to say, that column of the table is utter hogwash; beneath contempt.

I don't go rotten-cherry picking to find this stuff, and that's not an isolated instance. It's typical. By and large, the service documentation and 'training' material in this industry is a load of rubbish. That's across the board; all manufacturers.

And there's no 'solution'. People who can publish things like the 'recovery method' column in the Fujitsu alarms table are not reachable. They don't know any better and they don't give a bleep. They're locked into their witless orthodoxy, and they're not coming out for a look at the real world. You may as well talk to a cat or a potted plant as try to draw their attention to the fact that what they're producing is worthless dross, and they need to give what they're doing a rethink.

All I can say in closing is reader beware.

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