Moodring IC4 voltage issues

[Martan]

Hey all, hoping for some debug help. Just finished Moodring board. All IC voltages close to those in build report except IC4 pins 1 (8.16), 2 (8.16), and 3 (0.4). Those pins have continuity with correct parts, and nearby ground connections are OK.
ANy ideas?

Thanks

[madbean]

Well that's definitely not good.
Try pulling the IC out. What voltage readings do you get on IC4?

[Martan]

Hi Brian,

Socket voltages are:

1 0.86*           8 8.68
2 0.68*           7 0.6*
3 0                 6 0.6*
4 0                 5 3.91

The * means they seem unstable and drop as I'm measuring. If I wait longer between measurements they are higher. With audioprobe I get sound up until C5, then nothing. Have replaced C5 and IC4 and no change.
BYP has continuity with R8 an R9 (wired for true bypass). VB reading 4.5 leading up to R9. I've only hooked up 9V (T and S) and in and out to test rig if that matters. Dry signal passes through fine.

[madbean]

That is very strange. With no IC in there you should have some voltage on pin3 and no voltage at all on pins 1 and 2.

If you are doing regular bypass, you only need R9 and can leave R8 off.

I'm actually wondering if your C9 is leaky. We need to determine how you are getting voltage on pins 1 and 2 when there should be no DC. I'm not sure how easy it is for you to re-work the PCB, but perhaps removing C9 and testing the voltages again is a good idea. That would tell us if the cap is leaky, or perhaps there is some solder or trace bridge on that IC. Perhaps a close up pic of that area would be good, too.

[Martan]

Ok. Removed socket and pin 3 gave 4 volts, then removed C9 and got zero volts on pins 1 & 2. Bad socket and leaky cap. Thanks for your help!