Bizhub 751

[hassan123]

Hello everyone..
I have bizhub 751.
Show error c3503..
Normally this error remove after resting or found something wrong in heater section.
But i changed complete heater section even checked same heater on other machine it's work fine..
After that i change relay, power supply even printer control board, adu unit but problem still same..
Have any idea or issue have anyone face in past??

[hassan123]

When i was open the front door i checked aftar reset the error code c3503..
Heater lamp is on continously..
Even machine in ready position.
Look like thermistor not work.. but same heater work on another machine... after some copies the code return..
Issue is heater lamp not cutoff after ready to copy position

[mearmi]

Yes it is heater section Low or High fusing temperature error code.
Reset it first
You have to press utilitty mode and switch inside door switch on and off.
then RESET appears with arrow yes.

Printer control board (PRCB)
Fusing heater lamp /1 (L2)
Fusing heater lamp /2 (L3)
Fusing heater lamp /3 (L4)
Thermistor /1 (TH1)
Thermistor /2 (TH2)

[hassan123]

Reset soo many times.
Even checked pcb.
Checked lamp thermistor fuse everything..
But still same problem.. 😐😕

[tsbservice]

I don't know this exact model but the logic is always like: lamps/heating elements turn on, thermistors continuously measure temperature and report back to control board, when desired temperature is reached control board sends signal to stop heating. If your fuser works in another machine you could check wiring diagrams what is fuser control board and how it applies cut off to heating elements.
Also machine may have some ICP blown...

[3ktlc]

This is going to sound off the wall. Had this model giving this code years ago. Turned out to be a dirty drum sensor. How that affected the heating element, I have no clue. But, whenever this happened I cleaned that sensor and problem cleared.

[manuelcorrea]

After replacing defective parts in fusing unit remember to change DIPSW

[copyman]

Can't add much as I never had that code but had many other issues like toner dumping in machine, etc etc !!!

I just stripped a complete machine if you end up needing a board or something.

[bizhubber]

Check fuser drive assy . The gear that mates to the fuser unit is on spring loaded arm and the pivot gets gummy on old boxes. The rollers need to rotate when warming up to spread heat evenly, if not you can get an over temp code with different fuser units. If it is sticky, you can add lube from the front without removing back panels, etc.. Worth a check, anyway.