Troubleshooting an Aion Vector (Deep Blue Delay)

[rmjlmartin]

Hi everyone, and thanks in advance for your help.

I have an Aion Vector delay (the original, not the newer 125b version) build that someone else did that I'm trying to troubleshoot. The build document is available here- https://aionelectronics.com/project/vector-deep-blue-delay-clone/  It's built as the Deep Blue Delay, not the Rebote 2.5.

The problem it has is that while the dry signal comes through fine, the echo is static. Not a little fuzzy, but completely static. (completely distorted, maybe?)

I've been through the circuit and found a couple of incorrect resistors, which I changed, and the current-limiting led (D2) was reversed, which I also corrected. But, neither of those made any difference. With my audio probe, I get a good, clean signal to the C5 side of R7, but on the other side of R7, the echo turns to static. Measuring C6 in the circuit with my capacitance meter gave me a really weird reading, so I replaced it, but the new capacitor doesn't make any difference, and the old one reads correctly out of the circuit.

I also tried a couple more PT2399 chips, one out of a working delay that I built, and tried this one in the other delay. This one works in the other pedal, and none of the others make any difference in this pedal. I've also looked for solder bridges and damaged traces, but I haven't found any yet.

The voltages on the ICs are (using a Boss PSA power supply)-
PT2399-
Pin 1- 5.05
2- 2.52
3- 0
4- 0
5- 2.88
6- 2.52
7- 1.77
8- 1.97
9-16- 2.52

TL072-
Pin 1- 4.45
2- 4.45
3- 4.42
4- 0
5- 4.42
6- 4.45
7- 4.45
8- 8.90

I've attached a gut shot, too.

This is the first time I've done any troubleshooting on a PT2399 circuit, so I'm a little out of my depth. Again, thanks very much for taking the time to read this and offer your input.

[ElectricDruid]

The power supply voltages look ok, and the TL072 looks good too, so that's all positive.

Most of the voltages around the PT2399 seem to be fine. So I'd guess it's a question of how far the signal gets to find the problem. Is there signal at pin 15 of the PT2399? (the point marked 'delay in' on the schematic - after the pre-delay filter).

HTH,
Tom

[rmjlmartin]

Thanks Tom, I appreciate the suggestion. I did have the signal at pin 15 of the PT2399, so that wasn't the problem. But...

I'm happy to report that it is fixed.

The problem was a cut trace on the pcb between C10 and pin 8 of the PT2399. Most of the components on this build were cut off dead flush with the board, and it looks like the person who did it snagged the edge of the solder pad where the trace meets up to it and cut the trace.

So, with the trace repaired, everything works as it should. Hopefully this will help someone else out. It certainly had me stumped for awhile!