HP 8150 print fades

[Ed-printer]

Any ideal why this printer prints dark at the top and gradually fades out toward the bottom of the page? Like on the config page the top part is fine but by the time it gets to the toner gauge the print is really faint. I have replaced the fuser and toner cartridge with a known working 8150 but nothing has helped. Any ideals would be appreciated. Also I adjusted the print quality from within the control panel--still no go. Thanks in advance

[MichaelTech]

H/V assy. may be intermittantly failing. DC cont. also. Even a failing P/S could be it.

[ptjeff1]

Since the 8150 prints with the leading edge being the long edge of an 8.5x11 inch paper (right side), when you say the bottom of the page is light that would mean it is the left side of the paper path if you are facing the printer from the right side. Anyways, your transfer roller might not be seated correctly on that side. Also, a more remote possibility is that the scanner is dirty.

[Ed-printer]

H/V assy. may be intermittantly failing. DC cont. also. Even a failing P/S could be it.
Thanks for the input, I was leaning toward the hi voltage ps but wasn't 100% sure, I believe that is the assembley that puts the charge on the paper to attract the toner, I have ordered a hi voltage ps and transfer roller assy and will let you know if this solves the problem. I have never seen this issue before. Also thanks for the other reply and I checked the transfer latches and they were down in the released position.

[Praveen]

Hi,

clean printer sacnner glases, contacts and flat cable and tray after it, must be it will work.

bye praveen

[Ed-printer]

Hi, thanks for the reply and that may very well resolve the issue, as an update to my previous post I replaced the transfer roller which had gray shadow where the faint print was coming from, but it is still doing the same, thought for sure that was it, I still have a hsvp that I have not replaced to see if that is the issue. This is an issue that is difficult to resolve, any input would be appreciated. Will keep you posted and thanks for the input.

[raz]

did you check or clean the contacs in the cartridge slot?

[Ed-printer]

Laser unit is the next part to try, I did a print on the 8150 services manual today and searched it throughly never found anything that relates to a faded print at the bottom of the page. I am just going to tear it completely down with vacuum in hand and rebuild it. Thanks for all the suggestions and will appreciate any additional input. This one is becoming a pain, better yet it may be something super simple, lol.

[redcow]

You sluffed over Jeff's reply.
Where is it fading. The bottom of the 8.5" sheet or the side that's 11" ?

[Ed-printer]

Sorry, the bottom of the 8.5 inch page

[ptjeff1]

Have you done a half-way test? Are both of the pressure tabs on the fuser down? If one is up and the other down you will have fusing problems on one side of the page. Did you re-seat the transfer roller, are both of the white bushings in the transfer roller receptacle in place?

[Ed-printer]

this is unbelieveable, I managed to find a working 8150 that has been taken out of production, after determining the unit was functional I grabbed the optics unit, transfer assy an ep catridge, installed it and still no-go. I took the advice of the half-test and yes the image on the drum is lighter on one side as opposed to the other. One suggestion I received was the dc controller may be faulty, it supplies the voltages to the hi voltage ps, guess I will try it tommorrow and let you know what happens.

[Ed-printer]

Have you done a half-way test? Are both of the pressure tabs on the fuser down? If one is up and the other down you will have fusing problems on one side of the page. Did you re-seat the transfer roller, are both of the white bushings in the transfer roller receptacle in place?

Jeff, you know your stuff, sorry I posted before I saw it. In resonse both tabs are in the down position, I replaced the transfer roller assy with a working known 8150, and the bushing are intact, thanks I had never would have known to check that, without it I suppose the roller would just be free-wheeling the majority of the print process. I just wish these printers were side by side instead the printer I am robbing parts out of is about 60 miles away. Thanks for any insight you have, and as always I will report the final solution in case any one else gets bit by this problem

[MichaelTech]

Ok, it is an image formation issue. As the Half test shows.
This means: Laser is not completing a full pass. Image is corrupt.
Question; is this the internal pages, or sent pages? Pull the formatter, and do an engine test. If ok, then replace the formatter.

[Ed-printer]

I replaced the Low Voltage Power Supply and the DC Controller today and the problem seems to be resolved. Thank you for all of your suggestions.

[Ed-printer]

Got a call back from the client today, same problem again, I am at the point where I am clueless, an outside source that got involved is suggesting RB2-3622-000cn--toner guide--which may make a little sense to me but not a lot--any help is appreciated, this is driving me crazy.

[ptjeff1]

It sounds like gremlins:D.

Let me know if I've missed anything, but so far the following have been replaced:
High voltage and low voltage power supply
DC controller
Scanner
transfer roller
toner cartridge
toner cartridge contacts cleaned(?)

Did you try removing the formatter and do an engine test as Michael suggested?

That covers the usual suspects. Now you get into the land of freakiness, like bad fans, displays, or something completely unrelated causing problems.
Maybe the Feeder Assembly, no. 16 in the diagram, RG5-4305?

[MichaelTech]

Ed, has this unit been dropped? Check the scanner again for proper installation. Check cables for a bent pin in the socket.
There just might be a short going on somehere. Check all cables.

[Ed-printer]

Thanks for all the help I have received on this issue, and promise to return the input if I can help. Seems last I spoke with the client on 12-12-2007 he would contact me if the problem needed further attention, as of today I have not heard back from him so I closed the ticket,,,let's just hope it somehow fixed itself,,never know it happens sometimes... Once again thanks again.