(small) Printer Repair list

For a while, I worked repairing PC printers.  Collected here are some original contributions, but mostly the collections of people with whom I've worked, in particular, Wes Hansen.

Please don't email me asking for help with your rig; I direct you to the Usenet newsgroup sci.electronics.repair .  I no longer work in this field and don't repair printers anymore.

Color Stylus II Set language =  black cleaning button on POR.
Registration = Reset on POR
DJ680C Green & Amber lights flash alternately OOPS bad on Sensor PCB C2164-67803
(thinks that there is always paper loaded)
DJ710, 720C, 820C, 1000C Self Test: With the power light ON, hold the power button, press the resume button 4 times, then release the power button.
LJII First page prints OK, subsequent pages are shifted down 1/2" Sticking registration solenoid, from residual magnetism.  Place a strip of vinyl tape (electrical tape) across the inside of the armature flap, where it hits the armature core.
LJII/III 50 Service [Notes: Printer must be turned OFF for 20 minutes minimum to clear the "50 Service" message from memory.  Even if you repair the problem, if you haven't left the power off for 20 minutes, you will still receive the "50 Service" message.
LJII: you can bypass the 20 minute wait by shorting C211 on the DC Controller board.
LJIID: you can bypass the 20 minute wait by shorting C216 on the DC Controller board.
LJII Series: there is a safety switch on the DC Controller which prevents the fuser from being powered if the printer's lower pan is removed and the printer switch is not activated.   This will give a false "50 Service".]

ACPS RG9-0319
C153 22uf 25v on upper ACPS board (most common)

Q101 BCR8DM-12L 600v 10a Triac; no ECG!
Sub Digikey Q6008L5-ND 600v 8a isolated TO-220ab
Remove the upper board to access it (no need to detach the lower PCB)
SSR101 Sharp S21MD4V Opto Triac driver
Can sub DigiKey MOC3082-MQT-MD

If the "50 Service" is intermittant, replace the fuser cable from DC Controller to Fusing Assy (Exit Sensor and thermistor PCB)
RG1-0907-050 ($6 from PrinterWorks)
RG1-0907-000CN ($19 from HP)
Access is from the lower pan.

Printer "Moans" at output when paper passes through RG1-0945-000CN Output Delivery Assy.
Rollers get hard and worn.
A good picture of this is here
This part goes in the "lid".  I remove the fusing assy to get to the screws, and even then it's really easiest if you then remove the lid altogether (four more screws) to replace the delivery assy.

Replace that, and it'll cure the moaning, guaranteed.  It will also tend to feed out a bit straighter, but that's a minor issue.  On the II/III, these almost never give any other symptom than the noise, and they'll continue to operate OK for a looong time making the moan.

LJIIP 12 Error C702 10uf 16v on print density PCB
52 Service Wrong scanner: 4si scanner (600dpi) in a IIIsi
55 Service C42 470uf 25v on DCPS board
R64 470 ohm on DCPS board

I acquired an HP IIIsi that exhibited the "55 Service" msg on powerup.  Symptoms included that the main motor wouldn't run within five seconds of poweron, which it should.  Having two of these critters allowed me to pin it down to the DC Power Supply.  Upon inspection, I found corrosion on R64 (470 ohm) and cap C42 (470uf 25v) to be leaking onto the PCB.  Replaced both, fixed.

To access, remove the right printer cover (two screws on lower edge, then slide it 3/4" to the back to release), the formatter cover (the large cover, not the 4" x 6" memory access hatch) with the fan attached (disconnect its harness after removing the cover's screws), then the formatter PCB complete with its pan and any interface board that's plugged into it.  Don't try to just remove the formatter PCB, as it won't do you any good.  You have to disconnect the three harnesses and remove the pan its in as one assembly.  When you have the formatter pan out of the way, you have access to the DC controller (the board on the left, toward the front) and the DC Power Supply (the board in the center).  Only two screws retain the DCPS's pan to the chassis, but six PS leads are screwed (4mm?) to the board and have to be removed.  Two harnesses on the right, three (?) on the left, and some cable clips.  Lift the DCPS' pan up 1/4" and tilt the top out toward you to remove.

About eight 3mm screws retain the PCB to the pan.  C42 is near the top left of the board as it is mounted in the printer, near an output connector header.

If you look up the "55" code for this model, they have you check for loose cables between the DC controller and DC power supply, then start replacing parts: DC controller, DC supply, formatter, main motor.  Gets expensive.

13.2 Error If the usual problems are not found, and a duplexer is installed, try removing the duplexer.  I found one bad DC Controller cause a "13.2" on powerup, only with duplexer installed.  Worked fine as long as the duplexer was not installed.
41.4 Service Wrong scanner: IIIsi scanner (300dpi) in a 4si
Notes on converting a IIIsi to a 4si Benefits: the 4si (later firmware) has Powersave, and is 600dpi.  If you have all the parts, it can be done. You'll need to swap in these 4si parts:

Formatter board.  Requires the "pan" it's in, too, because the form factor is different than the IIIsi (the 4si formatter is smaller).

DC Power Supply.  Because the power connector for the 4si formatter board is different.  All other connectors are OK.

DC Controller board.  Because the formatter formats data at 600dpi, and if you don't change the DC Controller, only half the page will print (widely expanded, at that).

Scanner.  Because the IIIsi is 300dpi, and the 4si is 600dpi.  If you don't swap the scanner out, you'll get a "41.4 Error" message.

Control Panel.  The same buttons all work, but the function of each is different.  The IIIsi Control panel will work OK, but you would have to relabel the buttons (or provide a map/legend for the user).

No cables have to be replaced, but the IIIsi Control Panel ribbon cable will have to be inverted (twisted) to fit into the 4si Formatter's socket -- it can be done, and works OK.

40x9 series Dead, no voltages from PS Blown solder at L2 in PS
OL400 Fusing error, fuser runs too hot Triac in PS which controls the bulb current is shorted.  M8GZ47 or ECG5620, 8A 800v

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