Some additional data from stuff I’ve checked:
VR1-6 voltage divider network as analog inputs to micro check out okay, measuring 0 to 5V input to micro itself. Meter placed on the shoulder (?) of the pin itself at the chip, example shown below). So I know each pot’s wiper is adjusting 0 to 5V smoothly and independently and the micro is seeing that voltage — measurement location rules out opens or shorts from pot all the way thru board, micro socket, to micro. Is it possible there is an internal short or break in the analog input section of the ATmega chip itself? I keep going back to something wrong with the micro probably because it’s not something I can check myself. Will prob just order a new one anyways simply to rule it out for my own sanity.
Example of where I’m measuring I/O voltage for micro when troubleshooting:
Other stuff:
Vref = Vcc = 5V, stable
P2 pins checked, 5V on pin 2, GND on pin 6, pins 1,3,4,5, continuity back to corresponding pins on micro.
P3 pins checked, 5V on pin 3, GND on 2 and 4, 1 open, continuity back to MIDI IN pin on micro
Phase switch works — at times when getting trem effect, can hear the difference between normal and harm trem.
Mode switch works — momentary/latched modes check out.
Footswitches open when not depressed, closed when depressed only.
Y1 probably working since when the effect does work, the tempo is steady. C5/C6 verified correct values.
Variable resistors & gain set per build manual.