Hi there, I've been away for the weekend but managed to have a quick look tonight. My oscilloscope is a primitive analogue so I'm a little limited. However I had a look at the pin 9 of of ic4 and ic5. They both seem to have the same 'small fast clock-like pattern (for want of better description). I checked gates 0-5 and all send out a 4v (my arp switch is broken - my replacements arrived last fri so will repair this week). I push a key 6 times and on each gate I will get 4v - one in six hits.
My lights do turn off on poly but not when hold is selected.
I checked power on all ic's around this area and they are getting the 5v dc (pin 16).
Other points noted:
Nothing on outputs from ic2 (will recheck this in the next few days)
ic 131 5vc on pin16, but -10dc appears on most of c131's outputs (constant)
I checked some outputs on the main cpu, most that I tested showed a square wave looking shape.
Once again, I will redo these checks next week. (and gather some more accurate info)
I just got home and thought I would have a quick look.
Thanks once again.