MP 6503 SC541/542

[fixthecopier]

This MP 6503 has a code of sc541-02, and sc542-02. The history shows a similar issue about a year ago. The tech replaced the thermisters, and when that didn't fix it he replaced the thermostats and said that did it. I have a 7502 at another local that codes and I just clean the thermisters and it's all good. On this machine I found the thermostat holder broke on one end. I replaced the holder, the thermostats and thermisters. It still codes. When I check the roller temp in sp mode, it shows the end thermister at 26, which would be room temp and the center is 0, which means it's open. I assume at this point I am looking for some kind of pinch or break in the circuit. I had to drop a loaner and send it back to the shop. Anyone have similar issues or suggestions?

[jonhiker]

check for a pinched wire on the center thermistor. we usually do not have much issues beyond cleaning the thermistors and resetting the code

[Oze]

With these beasts we have a couple of refurbed fusing assy's that we drop in when we have issues like this so that we don't have to do the loaner route.
The machine takes up so much room on it's own that there's generally no room to slap in a loaner as well.
It might well pay to order a complete fuser and totally rebuild the suspect unit as a spare?

[slimslob]

I had one where the locking tab for holding the contact pins for two of the lamp leads in the connection block were broken. When you static tested it with the fusing unit removed, all continuity checked good. When you put the fusing unit back in the machine, the leads would push and not make connection.

[TonerMunkeh]

I've had the connector block on the rear of the fuser cause 541, I've replaced it a couple of times in the past.

[fixthecopier]

Thanks for all the replies. I have it at my table in the shop now and no calls, so I have plenty of time to play with it.

[fixthecopier]

Checked all lamps. Pulled and reseated the connectors on the power supply and ac control board that would pertain to code. Still down. Boss doesn't want to buy a fuser or board. Have no twin machine to swap with.

[fixthecopier]

Issue resolved. The center thermostat, 211c, was popped. It was a new one, thus throwing me off on troubleshooting. I slammed it on the table a couple of times, and it reset. Thanks again for responding.

[Zaxxon]

Issue resolved. The center thermostat, 211c, was popped. It was a new one, thus throwing me off on troubleshooting. I slammed it on the table a couple of times, and it reset. Thanks again for responding.

Yeah, I love troubleshooting by slamming