Bizhub C7000 tray 4 problem

[dogsbody]

Hi Everyone,
We recently sold our showroom c7000 to a new customer and everything was perfect in the office but once we got it onsite tray 4 (LU-202) can't be selected. It is picked up by the print driver and shows on the operation panel however it is greyed out like in the images. We took the LCT to another machine and it worked fine, we've checked wiring and isolation dip switches, reloaded firmware and have managed to stump the guys at Konica who're leaning towards replacing boards. Before we go ordering expensive parts I thought I'd put it out there and see if anyone else has seen anything like this before? Images show whats happening, trays there but can't do anything with it.
Cheers.

Almost forgot, in service mode if you adjust restart timing as an example, and specify tray 4 it will light up green and feed from the tray. Choose a different tray on that screen and you can't go back to tray 4 with out exiting back into service mode.

[Mick01]

Hello,
I believe this was resolved by turning off the faulty isolation switch for tray 4 and 5 PFU (dipswitch 35-0 and 35-1 to off). It was strange these switches were causing this issue.
Kind Regards,
Your Friendly KM Tech support :-)

[Drcopy]

Im having a problem with not showing sra3 as an option in paper setting (tray 4 LFU), the guides are snug against the paper.