just finishing up my second sunking build, my first was a success but a little sloppy. this one was much neater with better components. but I'm having some issues. the only part sub was a 470n cap in the tone section instead of 390n. when testing I got only a faint sound. discoverd a reversed electro. fixed that and tested again and it sounded glorious until...I maxed the gain control and when hitting loud chords the circuit would oscilate with a rapid thumping beat until I backed off the gain, it would then stopped oscilating and soung great again. checked my voltages and all but a couple were in range most were .10-.15 high. I tracked down a solder bridge between pins 3 and 4 of the charge pump. fixed that and got only a faint thin tone when tested. I am at a loss. checked the voltages again and all but a few where in range. here are the voltages I got:
IC1 IC2 IC3
4.59 4.63 9.35
4.59 4.59 4.69
1.26 4.54 0.00
0.00 -8.84 -4.40
4.48 4.62 -8.88
4.60 4.68 4.86
4.61 4.65 4.15
9.35 16.98 9.34
I am still fairly new at this and not the best at debugging (been building about a year.) If you could take a look at these readings and maybe point in the right direction. it would be a real help. I you need some photo's I can take some In the morning. it's late now and the lighting in my house isn't bright enough for good pics. thanks so much.
never mind tried another 7660s and sounds great. no oscilations... full rich tone. seems I just needed to go to bed and rest my brian. those voltages are with the new charge pump. should I be at all concerned with the voltages that are more than a little off? maybe I should quit while I'm ahead. :-[
IC1 pin 3 measures low because the meter creates a voltage divider with R2 and pulls the voltage down. The rest of your measurements are correct given that your 9v measures at 9.35v. I think you're good to go.