asked Dec 13, 2007 at 4:00pm
Hp HP LaserJet 3100

"Printer signal error" on HP LaserJet 3100

I have an HP LaserJet 3100 that was working great, except starting to show blurry and faded print.

I ordered the "Blurry/Faded Print" repair instructions from this website and _carefully_ disassembled the printer and performed the cleaning procedure, which involved opening up the laser scanner unit and using cleaning fluid. I then _carefully_ reassembled and plugged everything back together and double-checked all my connections. However now when I try to print something I get 3 completely black pages (edge to edge) and a 4th page that is about 1/4 black and then the printer beeps and displays the message "Printer signal error". If I disconnect the power and re-power it, the error disappears. It comes back when the next print job is attempted.

I have the HP 3100 Service Manual and I reviewed all the tests and troubleshooting procedures. The same result happens if I use the engine test button on the bottom of the printer. The manual advises that I should "replace the laser scanner" if the error message persists.

I'm trying to be a little "green" and repair this printer rather than creating more electronic trash. Does anyone know what tests to run to identify whether the laser scanner is actually the problem (ie: did I break it by cleaning it), or it's something else? I'm willing to try replacing the laser scanner if I knew that was the problem for sure (I found a cheap refurbished one online). Any ideas?

During the procedure you have to remove the connectors to the scanner and replace them. These connectors have to be put back on firmly. This is the only part of the procedure where you could have messed up and input the black page problem. Recheck all the work you did in the scanner and around it.
by moe on Dec 13, 2007 at 8:30pm Add comment
I checked and re-seated my connections for the third time, and everything appears to be OK:

- The ribbon cable is not damaged and the board is properly mounted.

- The connector with 6 purple wires that plugs into the laser scanner is properly seated; the pins are not bent, the connector holes look clear. I pressed gently with a tiny screwdriver to ensure that it was fully seated.

I did find that if I leave the connector with 6 purple wires unplugged, then I get blank pages (instead of black), but the same "printer signal error". So, the connector is doing something.

One other clarifification: the "black" pages are really a streaky gray, but they go from edge to edge of the paper. I can take pictures of some samples if that would help troubleshoot.

What I'm really looking for is whether there is any pin test or continuity test I can run to determine which signal is missing? Is there such a test?

- davef
Post is somewhere so I can look at it, or click on my name and email it to me.
by moe on Dec 15, 2007 at 9:12pm Add comment
Take a look at this link to see a picture of the pages:


The gray is actually slightly lighter than it appears in the picture. When I send a print job, 3 full gray streaky pages come out and a 4th page is about 1/4 gray (as shown). Then the printer displays the error message "Printer signal error. Call for service".
- davef