C450 Background

[lanierboy]

Hi Everyone, I have a C450 Bizhub that after 20-30k the yellow IU gives background. I have changed IU+transfer belt and both HV boards but the machine still ruins the yellow IU and the only way to remove the background is to replace it. idea's ?

[JSC]

You need to fit modified toner seals and shutter, on all the toner hopper units as the fault starts on the yellow but will move on to the rest of the colour units.
You also get this fault on the C350's % C351's.

[lanierboy]

sorry forgot to mention that the seals and shutters have allready been replaced. cheers

[Frostwolf]

I had a c450 killing the Magenta I/U's minolta said to put a second level of seals on the hopper area, I saw no need in this as I could already tell they where sealing good enough. It was killing the I/U's about one a month, I ended up going on the call after the 6th I/U

I took apart and cleaned all the HV traces from HV boards and through the spring assemblys on the Print head assy, and checked OHM's on every connection, Once I was sure all was cleaned I reassembled it and its been running for 9 months now and no problems.

KNOCK KNOCK (on wood)

[texchar555]

hey make sure the contact springs are set properly. The springs need to be touching both of the poles on the hvt board and of course be cleaned.

[alfpanasonic]

I have a similar problem and the trouble was the laser unit