[BUILD] CAPI FC526~500 Series~FET Limiter Kit~Official Support Thread

[jsteiger]

Jeff! Thanks so much for responding. Aside from a snafu on a vp28, this is the first module that’s given me an issue out of the 10 I’ve built(6 vp28s, 3 bt50s and all op amps)

When I first built the unit, it was passing audio in bypass mode, and was passing audio and trying to compress when activated. Meters were working too.
I wasn’t sure how to cal it back then, just wanted to make sure it powered on without smoking. No smoke.…then when I got it on the test jig, it started acting weird. Long story short, i powered on lots of times to try and figure it out and there was no smoke. Then one day, when plugged into my APi rack, it started smoking.

For starters, I realized I had one connector on my test job backwards. So I’ll remedy that.

PR3 seems fine, but PR4 is slightly burnt. They both still read 10r. Should I replace them anyways?

D1 and D2 are installed correctly

As for DT05, R5 and R6 smoke immediately as soon as power hits it…..I’ll triple check the DT05 for build fails. I’ll try and add a pic when I get home

You probably have some misplaced transistors on the DTO5. The OCD in me would replace the discolored 10R.

 

[Kpaas]

You probably have some misplaced transistors on the DTO5. The OCD in me would replace the discolored 10R.

I’ll replace that this week, and check the resistors on the DT05. Thanks Jeff! Can’t wait to hear this thing.

KP

 

[Kpaas]

I replaced the DT05 yesterday, and put a working op-amp in. Fired it up, and no smoke. Passes audio in bypass with a sine wave, and I'm getting 10v at Tp9. When I engage the compressor, I get an Audio spike for a second or two, then it drops down to a few db more than the incoming signsl...nowhere near +7.75dbu....also, the Q-Bias trim pot doesn't seem to be doing anything...any ideas??

KP

 

[jsteiger]

I replaced the DT05 yesterday, and put a working op-amp in. Fired it up, and no smoke. Passes audio in bypass with a sine wave, and I'm getting 10v at Tp9. When I engage the compressor, I get an Audio spike for a second or two, then it drops down to a few db more than the incoming signsl...nowhere near +7.75dbu....also, the Q-Bias trim pot doesn't seem to be doing anything...any ideas??

KP

Gosh that's hard to try and pinpoint. I'd for sure start looking for multiple misplaced resistors.

 

[Kpaas]

Ha.

Gosh that's hard to try and pinpoint. I'd for sure start looking for multiple misplaced resistors.

alright. I’ll start there. I’m assuming it’s something in the audio path, could it be the DTO5?