[Jamming] Bizhub 754 feeding trays 3 and 4 at the same time

[Rikk811]

Hey all!
First time poster on this site.
I'm working on a Konica Minolta Bizhub 754 and have been having issues with tray 4. It would try and feed multiple pages, even if I try to make one copy. Tray 4 would also feed when I print/copy from tray 3.
I've already replaced the whole tray 4 feed assembly, hoping that that had an issue. Maybe the clutch for tray 4?
Any help would be appreciated

[Brett GS]

Re: Bizhub 754 feeding trays 3 and 4 at the same time

Hi
Take both tray 3 and 4 out and off their rails and check there is no small piece of paper stuck in the plugs if that makes sense.
I have had this issue and after a while i done what it said above and found a small piece of paper that was caysing the plug to not have proper connection with the machines connector.
Good luck,hope this helps.

Brett

[Rikk811]

Re: Bizhub 754 feeding trays 3 and 4 at the same time

Hi
Take both tray 3 and 4 out and off their rails and check there is no small piece of paper stuck in the plugs if that makes sense.
I have had this issue and after a while i done what it said above and found a small piece of paper that was caysing the plug to not have proper connection with the machines connector.
Good luck,hope this helps.

Brett

Thanks!
I looked for paper behind the trays, one of the first things i did. Didn't find any.
Placed a ticket with Konica, they suggested replacing the PRCB. We'll see how that goes when it comes in.

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[Rikk811]

Re: Bizhub 754 feeding trays 3 and 4 at the same time

Replaced PRCB-no help. Ordered MFPB, will see if that solves it

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[blackcat4866]

Re: Bizhub 754 feeding trays 3 and 4 at the same time

I can't really believe this thread has progressed to a PRCB, without discussion of the exact jam code. =^..^=

[femaster]

Re: Bizhub 754 feeding trays 3 and 4 at the same time

Wow, slow down a bit there! Board this, board that, feed unit this, have we done any basic troubleshooting yet? By your description, it sounds like the feed clutch on tray 4 is permanently engaged. Does tray 3 work fine (single and multiple pages) if you leave tray 4 pulled out? Yes? Pull the wire off the feed clutch in tray 4, push tray in. Does tray 3 still work properly in that configuration?

Reattach feed clutch wire, pull out tray 3, test tray 4; can you run single or multiple pages from tray 4?

On a side note of paper being stuck in the electrical connector in the copier, did you verify also there was no paper stuck on the connector on the tray?

Let us know what the jams codes are, if any, when you run the above tests, and what test you were running at the time you got the code.

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[Synthohol]

Re: Bizhub 754 feeding trays 3 and 4 at the same time

try isolating (unset) the trays 1 at a time.
if still feeds both there is something locked up.
also wouldn't be surprised if a zip-tie is causing it.

[Rikk811]

Re: Bizhub 754 feeding trays 3 and 4 at the same time

To clarify, I wasn't using this thread as my only means of information, and apologize for not providing all of the info. I work for a dealer that is Konica Minolta Pro Tech Certified, so we have an abundance of info from the manufacturer. However, I did not find anything relevant in their KnowledgeBase, or with other techs that I work with.
I keep getting a J14-01 (misfeed from tray 4). Tray 4 wants to feed multiple pages when only instructed for one. This happens when tray 3 is being used as well, tray 4 feeds at the same time.
I've already inspected both trays for foreign objects, as stated above, replaced tray 4 feed assembly (so that ruled out cluthes/gears related to that).
After doing this, I reached out to Konica Minolta themselves, and after explaining what has already been done, THEY recommended replacing the PRCB. After that did not solve it, THEY recommended to replace the MFPB. I'm abut to replace that now, if that doesn't resolve the issue, they want to replace the SSD. We will see how it goes.
Thanks for the info.

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[Rikk811]

Re: Bizhub 754 feeding trays 3 and 4 at the same time

Forgot to mention, if I pull tray 4 out, or disable it, tray 3 runs flawless. So it all has to do with tray 4. I think Konica Minolta didn't think about the board that controls trays 3 and 4. There may be some issues with that.
There has not been any trouble coded, just the jam from tray 4 and tray 3, if tray 4 is set

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[blackcat4866]

Re: Bizhub 754 feeding trays 3 and 4 at the same time

This might sound silly to you, but I would spend some time tracing down the wire harness between the pickup clutches at tray #3 & #4, and the MFPB. During all this disassembly/re-assembly a wire providing ground to one of these clutches may have been pinched to frame. Since most copiers are ground switching and the 24vdc is always present to the clutch, the moment the machine boots up, one of these clutches may be engaged. When the feed motor turns on, that clutch will feed paper, whether the MFPB signals it to or not. It's got a ground, so it will feed.

=^..^=

[copyman]

Re: Bizhub 754 feeding trays 3 and 4 at the same time

Exactly my thoughts blackcat. And exactly why I avoid calling K/M tech support. Always a bad board with them.

[femaster]

Re: Bizhub 754 feeding trays 3 and 4 at the same time

This might sound silly to you, but I would spend some time tracing down the wire harness between the pickup clutches at tray #3 & #4, and the MFPB. During all this disassembly/re-assembly a wire providing ground to one of these clutches may have been pinched to frame. Since most copiers are ground switching and the 24vdc is always present to the clutch, the moment the machine boots up, one of these clutches may be engaged. When the feed motor turns on, that clutch will feed paper, whether the MFPB signals it to or not. It's got a ground, so it will feed.

=^..^=

I concur, do a continuity check on the ground side of the clutch in tray 4 to find out if it's permanently grounded.

[EarthKmTech]

Re: Bizhub 754 feeding trays 3 and 4 at the same time

Prcb does not directly control the trays on this engine, the paper feed driver board does. (PWB-KH) and communicates to the PRCB by a flat cable. I have had this fault before where the tray continues to pickup additional sheets on a single page job after the first sheet is fed and then the machine stops with a jam detected at pickup, on this engine and the previous 652 series. It was this board in this instance. (PWB-KH)

[Gift]

Re: Bizhub 754 feeding trays 3 and 4 at the same time

Exactly my thoughts blackcat. And exactly why I avoid calling K/M tech support. Always a bad board with them.

[Rikk811]

Re: Bizhub 754 feeding trays 3 and 4 at the same time

Sorry for the delay all! And thank you for the feedback!
The problem has been resolved!!! It ended up being the paper feed drive board. When speaking to the agent at Konica, they said that they were looking at the manual and this machine didn't have that board, that's why they suggested the PRCB. I didn't even think to argue with him, and I didn't look at the service manual for it myself like i should've. But all is good to go now, and I know for the next time!
Thanks all!

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