Not sure what I did to my beloved smoothie and need some help. First, the circuit has been built and boxed weeks ago and has worked fine. Built it using all stock values on the BOM.
Last night I removed R3 (20k) and socketed it to try some lower values to increase the output of the pedal as it was below unity. Soldered in sockets, stuck in a 10k and played it, sounded good. Next I tried a 5k in the socket just to see how it would sound and.....dead.
The pedal has a VERY minimal output when engaged. I re-flowed thr R3 sockets but still no luck? Unboxed it and have it on the tester now. What the hell did I do to this thing?
Here are the voltages I am getting:
IC1:
1. 1.76
2. .93
3. .89
4. 0
5. 0
6. 5.09
7. 8.49
8. 9.27
IC2
1. 3.3 - 5.7 (varies)
2. 4.75
3. 1.3 - 8.8 (varies)
4. 9.27
5. 8.5
6. 8.45
7. 0
8. 0
I appreciate all help with this. Thank you.
Hey I solved the problem ;D
It was a failed 4.7 zener diode (D2). I was tracking power and found there was nothing at C11 and D2. I replaced the zener and bingo, back in business!
My question is why did the diode fail? Could me changing R3 to a lower value somehow do this? I am using a 10k now it all seems fine but I am reluctant to go lower than this. Or, was it just a fluke that the diode just happened to fail?
Any insight is appreciated.
I'd say it is a fluke. Changing R3 doesn't alter the voltage divider created by R24/D2. The 10k is fine. Glad you got it working :)