sharp MX-c402sc intermittant light copies

[driving lots of miles]

I have a Sharp MX-C402sc that is giving me light copies and prints very intermittently. the copier is 4 1/2 years old 410,000 copies. it has the latest firmware, it was sold new by us and all the maintenance has been done on time, OEM Sharp toner. it has new black developer and drum. Customer complaint was that it would randomly print out copies that were extremely light. Customer had samples, and it did not matter if it was a print job, through the ADF or off the glass. I was unable to duplicate on site, it was brought into the shop and only once printed out an unreadable copy. I swapped out every consumable part and could not get it to cause any more problems. We took it back and it worked great for 8 days and then started have the same problem again. It was in the shop for two weeks while they had another c402sc loaner which had no problems. Any ideas would be helpful, as they want me to bring the loaner back.

[JR2ALTA]

I had that and it was the transfer belt. If you replaced it maybe look at high voltage board or main drive unit

[danceswrabbit]

had a mxm465 with same symptoms. after replacing a LOT it ended up being the mfp pwb.

[moose55]

I had that and it was the transfer belt. If you replaced it maybe look at high voltage board or main drive unit

I would tend to second this. You say that all consumables were replaced. Did you replace the whole primary assembly? That is where I would start. The HV contacts for this machine are just "spring and wire" contacts. There is a lot of room in them for error. That would be my starting point.

[driving lots of miles]

The customer traded this machine in on a new MX-3071 so we will use it for parts and not spend any more time on it.