by munkustrap » Tue Jul 07, 2015 12:35 pm
from the Service Manual:
Control Surface: Control surface LEDs, including VPOT indicators are updated via SIPO shift Registers .....
in the block schematics on page 12 the control surface is marked as Switches LEDs and VPOts, so not the fader boards.
try the following: the ribbon cables (black connector and Grey cable) from brain board to the control surfaces may Need to be reseated. so disconnect and reconnect These plugs: (do this also on the control surface Cards, not only on the brain board)
- Brainboard J36 to Line control surface J36
- Brainboard J37 to Mic control surface J37
- Brainboard J35 to Output Card J35
check the supply voltage of each control surface Card !!! maybe one has a missing 5V. There are Fuses on the boards labled with FB## (measure behind These fuses to check if they are working.
I expect that you have a bad Connection on These cables, or you may have a missing 5V supply on one of These 3 control surface Cards.