HP Color LJ 3600 faint blacks

[mntech]

Hello,
I have a HP Color LaserJet 3600 printer that is printing the blacks super faint.

This machine was dropped off to us with a bad slide lever(that opens the drum shields and engages that drum coupling)

We replaced the slide lever and now the machine is printing very faint blacks, I've double checked everything in the drive section that was removed, and the connectors, etc. The customer never stated that there was an issue with the quality, and I'm waiting to hear back as to whether the problem was preexisting.

Tried a new black cartridge, verified drum and mag roller are spinning, cheated door to ensure its not a transfer issue(hardly any toner on drum during printing). I believe this may be a high voltage issue, usually if laser is bad, i can cover the silver contact on the cartridge with electrical tape, and the machine will print that color solid across page, but in this case, i get no black at all... so i think the laser is fine, but drum or dev is not getting the correct charge/voltage.


Thanks in advance for any replies.

-MNTech

p.s. couldn't upload the image, so here is a link to the example

[austonrush]

Re: HP Color LJ 3600 faint blacks

Definitely looks like the high voltage board.

[Lance15]

Re: HP Color LJ 3600 faint blacks

Make sure all the clips on the contact-holder assembly are seated correctly.Pages from 3000, 3600, 3800.jpg

Burned me a time or two.

[Printerdude]

Re: HP Color LJ 3600 faint blacks

As Lance stated, sometimes the clips from the contact-holder assembly breaks and won't hold the HV board flush with the contact-holder assembly, will cause no voltage to toner cartridges. I know you tried a new black toner, did you try a color toner into the black toner slot just to eliminate a toner cartridge issue? Can't rule out transfer belt just yet, seen transfer cause this problem as well.

[mntech]

Re: HP Color LJ 3600 faint blacks

I'll have to check those clips tomorrow.
I swapped yellow and black, then yellow went missing, so I know it is that slot, and not the cartridge.

I believe transfer is good, if I let the the machine boot, then print a supply page with door cheated, I see little to no toner on black drum as paper comes up to it

Sent from my SM-G955U using Tapatalk

[mntech]

Re: HP Color LJ 3600 faint blacks

Clips were intact and hv board was holding flush to contact holders, double checked continuity from hv board to contacts inside machine just to be sure.

Customer got back to me, unfortunately they are saying they had no quality issues prior to the slide lever breaking. At this point I assume it may be something that I mucked up, although I have replaced plenty of these slide levers in the past, and never had any issues. Would there be anything around the drive assembly that could cause this issue?

Seems to be the HV board, but not sure why it would have failed during repairs of the slide lever.

-MNTECH

[Lance15]

Re: HP Color LJ 3600 faint blacks

That's the only thing I've personally come across with (mainly) issues with black.

The HVPS was all put back and all the contacts are seated correctly and everything?

Did any of the contacts for the black get dislodged on the contact-holder assembly?

[mntech]

Re: HP Color LJ 3600 faint blacks

Contacts are secure and making good contact with both the hv board and the drum unit

[mntech]

Re: HP Color LJ 3600 faint blacks

Fixed.

The cam lever that contacts the cartridges to engage/disengage contact between the mag roller and drum was slightly out of place.

Must have been bumped when re-install the drive assembly, enough to not allow the mag roller to be close enough to the drum, but not enough out of position to look obvious or trip the home position sensor on the shaft.

-MNTECH