Konica Minolta Bizhub 750i – Paper Feeding Issues from Tray 1 & Tray 2

[Yazaankhan701]

Hello everyone,
I've been troubleshooting a Bizhub 750i for the past two months and need expert advice. The issue is mainly related to Tray 1 and Tray 2. Below is everything I have tested and replaced so far.


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Issue Description

Tray 3 and Tray 4: Work perfectly without any issues.

Tray 2: When I try to print from Tray 2, the paper does not come out of Tray 2 at all. Instead, it tries to feed from Tray 1, and then the paper gets stuck in Tray 1, causing the machine to show an error.

Tray 1:

The feed motor makes a repeating "O O O" sound as if it's trying to pull the paper but struggles.

The motor runs, then stops, runs, then stops—like it's attempting to pull paper but failing.

Sometimes, the machine doesn't take even a single sheet before stopping.

Other times, it prints one or two sheets with delays (15-30 seconds between each page) before stopping with an error.


Bypass 3: Was showing incorrect paper size detection. I have physically disconnected it to eliminate it as a factor.



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What I Have Tried So Far

✔ Firmware:

Upgraded to FW00028 successfully.

Firmware downgrade (FW00027) is not working – the machine does not boot into firmware flashing mode when downgrading.

Used multiple firmware versions, but the issue persists.


✔ Hardware Replacements & Checks:

Mainboard replaced.

Memory board replaced.

TPM board replaced.

SSD was not replaced but physically formatted.

Motors and clutches replaced (taken from a working machine).

Motor driver board checked.


✔ Physical Inspections:

Swapped Tray 1 and Tray 2 positions, but the issue remained the same.

Checked and realigned paper feed mechanisms.

Verified all wiring and connectors.


✔ Electrical Checks:

Stable power input with no abnormal fluctuations.



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Key Observations & Questions for Experts

1. Why is Tray 2 not feeding paper and instead triggering Tray 1?


2. Why does the motor on Tray 1 struggle, making a repeating noise, and sometimes take long pauses before printing?


3. Is there a way to force downgrade the firmware to FW00027?


4. Could this be a sensor issue, board misconfiguration, or software-related problem?


5. Are there any hidden settings or service mode calibrations that I should check?



Any help or guidance would be greatly appreciated!

[kingarthur]

What happens when you try to print from tray 1, does it try to print from tray 1 or 2. Not sure what you mean by the FW, FW0027 is for the C750i - so you can't install it in the mono version, besides it's the FW version you need, not the FW0028, as FW0028/27 etc is the identifier for each model- the latest version is G00-RF, and you have to change the FV once you've updated it

[blackcat4866]

Did you notice what jam codes you were getting?

[AlaskaCopyTech]

Did you replace any feed tires? Did you pull out a tray and then try this experiment?

[Yazaankhan701]

kingarthur When I try to print from Tray 1, the motor runs and stops initially, almost as if it’s trying to pull paper. On the second or third attempt, the machine eventually pulls paper from Tray 1. Sometimes it gives an error, and other times it prints two sheets or a maximum of three before stopping. The machine rarely prints more than one sheet before stopping and giving an error; sometimes, it doesn’t print at all and gives an error, and other times it stops after just two sheets. The error code from Tray 1 is (11-05).

Additionally, the machine is not pulling paper from Tray 2. It always forces paper from Tray 1, even when Tray 2 is selected, causing a jam error. When I open the side panel, I can see that the paper is coming from Tray 1, even though Tray 2 is selected manually. Trays 3 and 4 are working normally. I even tried physically removing Tray 1 and printing from Tray 2, but the problem persists. I also turned off Tray 1 in service mode, but it still forces paper from Tray 1 when Tray 2 is selected. The error code from Tray 2 is (12-05).

Sorry for the unclear explanation. The current firmware running on the machine is (ACV7OYO-F321-GC3-RE(00)), and I tried to flash the firmware version (ACKNOYO-F321-GG3-RE(00)), but the machine doesn't boot into the firmware update screen when using the method “hold stop/utility key and turn on the machine.”

I hope this clarifies the issue. Please let me know if you need any additional information, or if you would like me to send a video. It’s really becoming quite frustrating.

Thank you for your assistance.

[Yazaankhan701]

blackcat4866 Yes, the jam codes are:

• Tray 1: Error Code (11-05)
• Tray 2: Error Code (12-05). Thank you for your support.

[Yazaankhan701]

AlaskaCopyTech Yes, I replaced the feed tires with all new ones. I also tried it with a working machine, but the issue is still happening.

[kingarthur]

Because ACKN0Y0 is for the colour version and it won't work for the mono version, as I've previously said. The latest FW is G00-RF. What happens when you carry out load tests on the motors, are the correct motors turning, the correct clutches activating, what happens when you test the sensors, are the correct sensors corresponding on the screen . What size paper does it think that tray 2 has, if the trays are set to auto select, and it thinks tray 2 has the wrong size, then it will print on the tray that has the correct size paper. if you go into Auto select, and tray 1, is set at the top, then move tray 3 or 4 to the top, set the paper to whatever is in tray 1, and see if it tries to print to whatever is now at the top.

[blackcat4866]

11-05 and 12-05 indicate that the paper is not picking up, not reaching the first paper sensor for each tray.
If you can hear the motor running to pick up the paper that's good. Does the machine leave scuff marks on the top of the paper, as if it's rubbing the roller against the paper but the paper isn't moving? A common reason the paper does not pick up is that the lift plate has not lifted the paper high enough to make good contact with the pickup rollers, or it lifts uneven.

[Albonline]

First question, did these trays ever work? second question if they worked before what has changed/happed to the machine to make them not?

[tsbservice]

I think you somehow confused machine either by putting in it wrong - parts, firmware.
You must get back to the point when it started preferably with original parts.