[Error Code] Ricoh MP C300 with SC552/551

[DRichard]

MP C300 has SC552 (sometimes will display SC551). This indicates fusing roller thermistor (or thermopile in the case of the 551 code.) Over the course of repair we have changed the thermistor, the thermopile, the entire fuser assembly, the power supply and the BCU. I have also reflashed firmware.
Each time the code(s) have appeared we have reset them using service mode 5-810. Upon powering the machine back on, it comes to ready, but within a couple of seconds one of these codes will reappear. We have confirmed the codes ARE RESETTING. The fusing unit DOES ROTATE. Only once did it allow us to complete a run of twenty test copies.
We are probably just going to write this one off and use it for parts, but I thought this would be interesting fodder for discussion. Enjoy!

[sandmanmac]

Re: Ricoh MP C300 with SC552/551

Check and clean the plug connectors between fusing unit and machine

[DRichard]

Re: Ricoh MP C300 with SC552/551

Check and clean the plug connectors between fusing unit and machine

Done. No change.

[Iowatech]

Re: Ricoh MP C300 with SC552/551

Once you get the machine back to the shop, don't part it out right away. Instead, see if it will work as a tech copier/printer.
The reason for that is it sounds a little like the location where the machine is at may have dodgy power provided from the outlet the machine is plugged into. That can cause all sorts of wrong and stupid errors to occur.
You won't be out anything if you do that, you can still part the machine out or toss the entire thing into the hopper if the errors reoccur.

[DougD]

Re: Ricoh MP C300 with SC552/551

According to the schematic, there are 2 pass-through-frame connectors in the harness between the fuser connector and the BCU.
I would take a close look at the male pins on both sides of each joiner if you haven't already done so.
See CN35 & 36 in the attached diagram.