FET Rack comp Rev D Hairball Kit Signal Issues

Hi Guys,

I'm trying to calibrate the rev D Hairball FET Rack compressor I've just built and it gets signal coming in fine and the VU metre seems to be working, however no signal is coming out of the unit, any suggestions on why this could be happening or troubleshooting techniques?

Cheers

Hi mjenk,

First thing is to check your wiring - no one is immune to wiring mistakes - no one.

Second, check your voltages against the mnats schematic here: http://mnats.net/files/1176REVD_VOLTS.pdf

Also try to verify your resistor values. You can go online and find a resistor color band calculator and you can make sure you stuffed the correct resistors in the correct places. Here's a nifty online calculator I've used: https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-resistor-color-code-4-band

Also check to make sure you didn't reverse any transistors, and that you used the correct pinouts.

If that doesn't help, consider reflowing your solder joints. So many mysterious problems disappear a lot of times when you take the time to reflow your solder joints. A cold solder joint can be very sneaky.

If that still doesn't work, you can trace the signal using an oscilloscope, or somewhere on this forum there's a suggestion for how to make a cheap signal tracer.

Just my $.02; I'm sure others may have some good suggestions for you too!

Mike

Thanks for that!

if anyone has had the same problem or some more troubleshooting ideas they would be most welcome as well, this is a great place to start though thanks!