hp laserjet 4250n

[MLS5262]

trying to troubleshoot a hp lj4250n. the unit will power up to a ready status, but.....

display will show tray 2 lifting, but it doesn't lift, doesn't give an error message and goes to a ready state.

tried a paper path test from tray 1 or 2, the unit shows processing job, but does not try to pick up paper or any other function and it does not give an error message.

engine test just shows processing job, but does not try to actually print anything.

the only things i've tried is reseating the tray 2 lift motor and reseating the formatter, and reseating memory dimm.

please let me know what other information would be useful to you to help resolve this issue.

thanks

[Big Al]

I'm not familiar with this model. Most have a small hole in the side for access to the Engine Test Switch. If it will print the test page then the printer is
working. That points it to the formatter? Have you downloaded the service manual?

Al

[MLS5262]

when I try to perform an engine test page the display shows 'processing job' but no other action takes place. the service manual does not address this issue directly that i can see.

thanks for the input

[ridered74]

Get some canned air with the long small air tube attached to it. Take the toner cartridge out, in front of the registration assembly there are three sensors. Aim the air tube in each one and blow them out real good.

[MLS5262]

no paper is being pulled from either tray, so paper is not getting to the registration sensors. neither paper tray will lift, display shows 'tray 2 lifting', but it doesn't and it doesn't give an error. if you send a print job, the display shows processing job, but no job is printed and no error is given. would dirty registration sensors cause this?

thanks for the input

[cs_steve]

Some things you could try:

1. Swap in an alternate cassette paper tray from another working machine -- since Tray 2 doesn't lift on startup but reads as the machine is attempting to do so, it'd be a good start.

2. I would try printing a configuration page, from Tray 1 -- this time make sure there is no paper in Tray 2, and actually pull Tray 2 out of the machine so it won't even register it's presence. Then try a configuration page or similar from Tray 1. The printer may be trying to pull from Tray 2 even though you're asking it to print from Tray 1.

3. If you have a spare fuser around from another working model, try swapping fusers. Could be a rare (strange) warmup issue where the fuser never reaches full temperature but fails to trigger a 50.x error. Haven't seen it on this model but it will certainly do this endless "Processing Job" on its newer cousin (the P4015 series).

Other than that, we'd probably be looking at a DC controller failure. I think you can safely rule out the formatter board as your culprit since it also fails to print with an engine test.

[ridered74]

no paper is being pulled from either tray, so paper is not getting to the registration sensors. neither paper tray will lift, display shows 'tray 2 lifting', but it doesn't and it doesn't give an error. if you send a print job, the display shows processing job, but no job is printed and no error is given. would dirty registration sensors cause this?

thanks for the input
I don't remember well enough to say yes for sure, but they cause several different extremely weird errors that make absolutely no sense. Can't remember exactly all the different ones I've run into, but blowing out those sensors has become step 1 for any weird problem on the 4250/4350's for me.

[MLS5262]

after replacing the dc controller the unit detected the jam in the registration area.

many thanks to all who replied

have a great weekend.