bh c451 error c-3725

[mik77]

I mounted the new fuser about 2 months ago on the bizhub C451. After about a month he started to give the error code c-3725. At first it gave once a week or so. Then he started to give it 3 or 4 times a day. I changed the thermal probes (taken from another fuser good) and mounted on an 'other car, carefully by trial for 15 days, working perfectly. So I install it on his machine and after 2 or 3 days I called the customer and told me that the machine starts to give the error code c-3725 ......
I would be very grateful for help

[aAandy]

Re: bh c451 error c-3725

I mounted the new fuser about 2 months ago on the bizhub C451. After about a month he started to give the error code c-3725. At first it gave once a week or so. Then he started to give it 3 or 4 times a day. I changed the thermal probes (taken from another fuser good) and mounted on an 'other car, carefully by trial for 15 days, working perfectly. So I install it on his machine and after 2 or 3 days I called the customer and told me that the machine starts to give the error code c-3725 ......
I would be very grateful for help

fuser temp high - this tells me the thermistors are doing their job, else they would not register a high temp in the first place - it also indicates the fuser is heating after the thermistors have registered correct temp,,, which suggests the fuser lamps are not being turned off,,, possible relay drive board (REDB) or control board (PRCB) issue, though i would be inclined to look for poor soldering on the relay drive board

have you followed the fault finding solution from the service manual?

16.5.68 C3725: Fusing abnormally high temperature detection (NC sensor)
Relevant parts
Fusing unit Printer control board (PRCB)

1 Check the fusing unit for correct installation
(whether it is secured in position).

2 Check the fusing unit, PRCB for proper
connection and correct or change as
necessary.

3 Reinstall fusing unit
4 Change fusing unit
5 Change PRCB

Relevant parts
Fusing unit IH power supply (IHPU)
Relay drive board (REDB)
Printer control board (PRCB)

1 Check the fusing unit for correct installation
(whether it is secured in position).

2 Check the open/close operation of the
upper right door.

3 Check the fusing unit, IHPU, MFPB and
REDB for proper connection and correct or
change as necessary.

4 Change fusing unit
5 Change IHPU
6 Change PRCB
7 Change REDB