PWB failure on MX 3501

[vincent64]

Brand new MX 3501, less then 1500 total, B/W and Color, the sub driver PWB goes bad, you can see the burn mark from the chip that went south, this PWB controls the primary transfer belt motor, not letting it turn, and causing it to jam where Pri and Sec. transfer belts meet.
There is no code for this, mach will come to ready, myself and another tech found it strange it can do Process Control with out the belt moving.
Anyone else seen this PWB go bad so soon, or any ideas what may have happend here, and yes the transfer belt, both of them, turn free.

[Nachoman4life]

Pwb prob

Ive never seen do it to its self I bet you have a short somewhere. (lost a driver pwb on a mx5500, pinched the wire harness to the fuser motor when installing the RBX unit. It was one of the transistor arrays, (common to many models before it) replaced the array (lucky very little trace damage) and all is good)

[KyoceraChris]

i concur with nachoman..

[OMD-227]

You are right in wondering how Procon was completed when the Primary Belt is not moving. During Procon, the machine puts patches on the belt, which are read by the Procon sensor. If you were simply powering on the machine, it will warmup and become 'Ready' when the belt is damaged/not rotating, but the values of Procon are not saved. I've had a few machines in the past with a broken belt drive gear, so the gear is turning, but the belt is not. The machine comes up to ready each time, and actually tries to print because the drum & secondary belt rotations are trying to turn the primary belt as well just by them touching each other/friction between them.