[sdiy] Diagnosing Fatman problem

[James Howe]

I've just completed building a Paia Fatman synthesizer as my first DIY  
synth.  Unfortunately it's not completely working.  It powers on just  
fine, no overheating or smoking.  The MIDI input works just fine (the MIDI  
light flashes as expected in response to keyboard input), as does the MIDI  
thru.  My current problem is that the Gate LED does not light up when a  
key is struck on the keyboard.  Since I am fairly new to doing electronics  
work I fully expected that I might have some bad solder joints, but I've  
looked and have yet to find one that might be causing a problem.

Based on some tips from Paia, I checked voltages on various IC's (1, 2, 3  
and 4) and the values seem to be consistent with the schematic (e.g. I'm  
not finding a voltage on Pin X of IC1 and no voltage on the related pins  
on the other IC's)  I know that the Gate LED will in fact light up since  
it lit up on me when I accidentally shorted out pins 4 and 5 (I think it  
was those two) on IC1, when I was trying to get a meter reading for one of  
the pins.

I'm also fairly confident that the keyboard is transmitting on channel 1,  
and that is how my DIP switches are configured.  I'm hoping that someone  
out there has some suggestions for ways that I can diagnose this problem.   
Unfortunately I don't have access to scope, only a digital multimeter.   
Are there specific places that I should be seeing certain voltages (or not  
seeing voltages) that would help me locate places where I may have a bad  
solder joint?

Any tips would be appreciated.

Thanks.

-- 
James Howe