HP Laserjet Enterprise M775 MFP - 13.A4.D4 / 3x500 jamming

[907tec]

Just took over an account with about a dozen of these boxes, so I don't have much history with them. One machine in particular (the most-often used, of course) is giving me some trouble. Machine is only about 1.5yrs old (sorry, don't have the meter, I would guess it's in the 150k neighborhood), but it sounds like it's been having issues with the 3x500 tray accessory for a long time. I should note: these machines are in a very dirty environment (silver/zinc mine), but nothing can be done about that.

On my first visit to machine, I was told that it jams constantly from each of the accessory trays. Event log showed endless 13.A4.D4 errors, along with a sprinkling of 13.A3.D3 and similar. Confirmed the jamming for myself and wasn't able to get a single page fed from trays 3/4/5.

Have already tried:

• swapping paper cassettes - no effect
• swapping feed, sep, pickup tires - no effect
• swapping paper deck controller boards - no effect
• swapped tray 3 paper feed assembly from a working machine - no effect
• All related sensors work properly in I/O check mode

Observing the paper feed with a tray removed, I can see that the pages are not being advanced by the pickup roll. Pages don't even reach the nip of the feed&sep rolls. When watching a working machine, I can see the pickup roller and arm drop when drive is engaged. However, it doesn't seem as though the pickup arm drops enough on the problem machine, so it doesn't make sufficient pressure on the paper stack.

Each of these trays has completely separate motors, clutches, size detect, and controller boards. Aside from some random issue with the formatter on the main body, I can't wrap my head around what could cause these all accessory trays to behave like that. Resorted to swapping the entire 3x500 tray unit with one from a parts machine. Despite being covered in 1/4" of dust, it worked immediately.

For a day.

Now I'm getting calls about that pesky 13.A4.D4 jam coming back constantly.

Any help? Or should I get the ball rolling on just replacing this thing?

*edit* Added additional steps taken

[theengel]

When you say "swapping," what does that mean? Did you install new parts?

[907tec]

Sorry, should have been more clear. By "swapping" I meant that I installed those components from a known-working machine. This customer has several of the same model scattered around.

[theengel]

No matter what, you should start by installing brand new feed, sep, & PU tires.

[wjurls]

Did you ever find a resolution for this? I'm having trouble with a 3x500 on an M725 at an Amazon Fulfillment Center. In my case the feed rollers for trays 5 and 6 appear to spin backwards. Tray 4 works fine. Looks like such a simple unit mechanically but suffers some weird issues.

Lee

[Phil B.]

Did you ever find a resolution for this? I'm having trouble with a 3x500 on an M725 at an Amazon Fulfillment Center. In my case the feed rollers for trays 5 and 6 appear to spin backwards. Tray 4 works fine. Looks like such a simple unit mechanically but suffers some weird issues.

Lee

what rollers spin backwards?

do you see prefeed d shaped rollers?

[wjurls]

what rollers spin backwards?

do you see prefeed d shaped rollers?

I don't see d shaped rollers. the pre-rollers are round. In thjs case, the upper feed, and separation rollers spin backwards while the pre-feed are stationary. Machine then indicates misfeed.

[907tec]

I'm sorry to report that I never did get to the bottom of this issue. We replaced it with a used Konica Minolta C454e and never looked back.

Though I haven't had a lot of experience with this series of HP, I am thoroughly unimpressed. Even more so after seeing how much they cost new.

[Jessetech]

small grey rollers which is pick up are the same or look like the hp m4555...………….real easy to mix up..and I take it you didn't sell them these.….shaft is thicker thus tooth gears mesh up nice