Vintage Synth Repair

Hi Team,
Have any of you got an Arp Quadra?
I was wondering if you remove the processor/lead-mix/polyboard
interconnect board, if the presets/patch buttons still work on 
the touch panel?

I have a Quadra that is not responding to the touch panel.
When I received the synth the 2nd of the 5 volt reg. was putting
out 12 volts. This is the 5 volts that is connected to the 
lead-mix and polyboard, not the processor board.
The 5 volts to the processor board was and is normal.

I have purchased the 7400 series replacements for the lead-mix 
and polyboards, but need to know if the 12 volts may have 
reached the processor.

So if anyone could find out if the preset/patch buttons 
work without the interconnect board installed, 
that would be awesome! 


Thanks!!
GD