TH Custom Devil 2.0

[quazimoto]

Greetings! Recently built a Devil 2.0 and was having a few issues and was hoping somebody might have some suggestions that would help me debugg this unit. I get sound in bypass, not when the effect is engaged. I have gone over the board and all the components are correct values. The board was working at one point and then all of a sudden it was like the battery died ( I use a power supply). I removed the board from the enclosure and checked for grounding/touching issues. So far no luck. I used an audio probe to trace the signal up to Q1 where the sound stops. I get a signal on the gate but not through the source. The voltage on the drain is 9.12 volts. I tried to adjust the bias but the trimpot would only bring it down to about 8.25 volts. Is it not supposed to be around 4.5volts? Also the voltage at the source was .03v while the gate was about .5v. Q2 and Q3 are similar values. I tried switching with another PF5012 but nothing changed. I will post some pics tonight as I thought I took some yesterday while fiddling around with this.

[quazimoto]

Some pics of the board. Tested the potentiometers and they are working correctly. Going to try to do some continuity testing of the circuit when I find some time.

[zgrav]

if it worked and stopped, I'd start with swapping out transistors if they are socketed.  same for ICs.  mostly because they are more prone to failure than the other parts, and because it is easier to try those things before you start troubleshooting the circuit in earnest.

[quazimoto]

Thanks for the reply. I did swap transistors out. Still no go. I built another project using Jfets and I remember having to bias the drain to 4.5 volts. Not sure if it is the same on this but the trim pots do not let me dial down any farther than about 8.2 volts.