HP 4250 printer with image defect

[atadikohp]

So this printer was out of ink, customer put in an after market toner and the result was image defect as in the attachment. So they took that same toner cartridge to put it in another 4250 at the same site and it print out perfectly. They also put the use toner from the second printer and put into the first one, it also prints fine. So I decide to take that printer back to our shop to troubleshoot.
So far I have replace : Power supply board, formatter board, DC controller board, laser scanner without any luck, it still has the same defect print out in this printer with that toner.( This is about all the electronic devices in this printer) However this toner work fine in another printer. I also check the toner contact point on the cartridge and the printer itself.
At this point, I am fixated on finding out which cause this.
Any advise would be great. TIA

[Phil B.]

So this printer was out of ink, customer put in an after market toner and the result was image defect as in the attachment. So they took that same toner cartridge to put it in another 4250 at the same site and it print out perfectly. They also put the use toner from the second printer and put into the first one, it also prints fine. So I decide to take that printer back to our shop to troubleshoot.
So far I have replace : Power supply board, formatter board, DC controller board, laser scanner without any luck, it still has the same defect print out in this printer with that toner.( This is about all the electronic devices in this printer) However this toner work fine in another printer. I also check the toner contact point on the cartridge and the printer itself.
At this point, I am fixated on finding out which cause this.
Any advise would be great. TIA

looks like a voltage bias leak

any time you push/pull a HP toner from the slot .. the contacts for the drum can get get bent/out of place... also.. the transfer roller gets jiggled around.

vac out the contacts in the machine.. inspect for proper alignment.

also check the contacts for the the transfer roller.

what are the maintenance counts?

machine clean?

depending on "after market" brand.. some (china) are crap.

[BaconSteve]

Did you get this one repaired. My guess is a new transfer roller, had one kick my ass once. What was it?

[Phil B.]

So this printer was out of ink, customer put in an after market toner and the result was image defect as in the attachment. So they took that same toner cartridge to put it in another 4250 at the same site and it print out perfectly. They also put the use toner from the second printer and put into the first one, it also prints fine. So I decide to take that printer back to our shop to troubleshoot.
So far I have replace : Power supply board, formatter board, DC controller board, laser scanner without any luck, it still has the same defect print out in this printer with that toner.( This is about all the electronic devices in this printer) However this toner work fine in another printer. I also check the toner contact point on the cartridge and the printer itself.
At this point, I am fixated on finding out which cause this.
Any advise would be great. TIA

Hey man.. been a week .. we both say the same...

did you finger it out yet?

did you fix? what was it?

inquiring minds want to know!

a response would be nice.. or a Approval of our recommends?

[atadikohp]

So I finally got some time to work on it. Here is what I did: I transfer all these parts to the new printer frame: DC controller, formatter board, power supply, toner sensor switch, transfer roller and the printer print out fine.
I DO not see any thing wrong with toner contact on the old frame, but that is the only thing left . Still did not get the answer I was looking for.

[BaconSteve]

Gremlins... friggin gremlins.

[Tom]

That was a lot of work just to satisfy your curiousity when changing the toners around fixed the problem. Those aftermarkets are dirt cheap, if I get one that doesn't work I just swap it out, and if it works in another machine even better.

[tech07]

I know this is an old post, but I had this exact issue today. Exact same image as one posted .New generic toner....Snakeskin dots. Put new generic cartridge in another 4250 and it works.

Was there ever a solution ? Insanity