(2x) 8-ball voltage at IC pin #3

[haymez]

My father and I have both attempted to build the 8-ball. We both reached the point where the board was completely wired and ready to test. We took voltage readings on the IC for both builds and everything was within acceptable tolerance EXCEPT for pin #3 - it is reading ~1.8v (documented value is 4.2v).

The *really* maddening aspect of this is that there are only 3 components: R1 (2M2), C1 (56n), and R2 (1M) and we have checked, double-checked, re-flowed, re-soldered, etc.

Help! Thanks.

[madbean]

At pin3 you have a 1M resistor going to virtual ground to supply the bias current to the op-amp. Your multimeter may be acting as a voltage divider when you measure the voltage with respect to actual ground causing the reading to seem lower. Try popping out the IC and re-measuring without a current load there. If the actual effect sounds right, I wouldn't worry about it.

[haymez]

Thanks for the reply, I will try that tonight. I was hoping there was an issue there because neither pedal works. Oh well, back to the drawing board.