Cerulean AION kit problem

[acostanza]

Hello everyone. Thank you in advance for any and all advice you can give me. This is my second effects build, but first with this kit. And I've got an issue for sure. I'm hoping you can help me find a starting point for diagnosing this kit build from AION.

The strange thing is that when the pedal is first powered up it seems to work fine for about 3-4 seconds. Then there is no sound for another couple seconds. Then a high pitched tone that falls in frequency from a whine to a quiet rumble. Then there is no sound. In bypass the signal passes through to the amp. There's no change in the power LED during any of this. It is on and bright. This situation occurs whether using a battery or power supply.

I've checked the voltages as recommended in the trouble shooting section of the kit instructions. Here's what I find:

Q1
Pin 1: V expected:7.8 | V probed: 3.8
Pin 2: V expected:1.0 | V probed: 3
Pin 3: V expected:0.0 | V probed: 0.0

IC1
Pin 1: V expected:4.8 | V probed: 9.2
Pin 2: V expected:4.8 | V probed: 9.0
Pin 3: V expected:4.8 | V probed: 9.3
Pin 4: V expected:0.0 | V probed: 0.0
Pin 5: V expected:4.4 | V probed: 8.4
Pin 6: V expected:4.8 | V probed: 8.7
Pin 7: V expected:4.8 | V probed: 8.7
Pin 8: V expected:9.7 | V probed: 9.3

Since it acts like a perfectly behaved pedal for a couple seconds when first powering it on I tried to quickly power it and read the IC voltage. But that doesn't seem to work. The voltage just starts at 0 and rises to the probed values above within a second.

With these very out of tolerance values I though I'd ask the experts for some advice on where I might look first. Clearly something is not right!
Here's a picture of the boards. I took the connector board out thinking there might be a short when I installed it in the case, but it makes no difference. Same situation whether it is in the box or not.



Whatever advice you can give me, I truly appreciate as I begin down the road of diagnosing the problem!
Thanks,
-Adam

[PRR]

Welcome!

To help others help you, here's some info:
Project page: https://aionfx.com/project/cerulean-amp-overdrive/
PDF with schematic Page 24: https://aionfx.com/app/files/docs/cerulean_kit_documentation.pdf

Since a lot of your "4.5V" points are over 8V, I would wonder for the voltage at "VR" or C10. If something is not really grounded, Vr will be high and much of the opampery will follow.

[11-90-an]

Welcome also....

You didn't solder anything in the CX5 or C8... from the notes CX5 is not supposed to be filled in, so you need to put something in C8...

But that won't fix the whole problem. Please also check your solder joints, especially R9 and R10....

A picture on the solder side of the board would also be good...

Good luck!