Topics

I finally managed to get all of the components together to complete my L5 and I seem to be having two issues.   The most critical one is that I'm getting a high pitched squeal out of IC8.  The other is that the compressor might not be doing much/anything but I haven't gotten to calibrating the trimmer just yet due to the squeal problem.

When I first plugged it in to try it out, once I raised the master volume up at all, the thing squealed like hell.  Bypass was perfectly fine.  Using a signal tracer, I tracked it down to IC8 which was a JRC 4558 that I got from BYOC.  I pulled out IC8 and no squeal, all is good.  I put in a "JRC 4558" from Tayda and same squeal.  This is suggesting to me that the ICs aren't the problem, it's probably something new the surrounding componentry.   I'm going to do a deep dive inspection around that area once I clear the cobwebs, but if anyone has any thoughts as to what might induce that squeal, that may help to narrow down the problem.

As for the compressor, I've noticed that the LED stays on all the time, wether compressor is enabled or not, or if any signal is going through or not. I'm not sure if that's normal, or perhaps tied to it not yet being calibrated.  I can't really tell if it's doing much of anything if I fiddle with the knobs, though again, I should probably get the thing calibrated before I worry too much on that front. 

I picked up an Ibanez Tone Lok CF7 Chorus-Flanger off eBay for $8 that was listed as 'passing bypass but not affected signal'. Having picked up a few other pedals like this, I figured it's likely a pretty easy fix on the cheap.   So I just got it today and the description was mostly correct.  I did find that I could get it to switch on and work as expected, but it was definitely flakey.   I tested the switch itself with my DMM and it appears to switch ok, so I don't ink it's actually a mechanical issue.  I noticed on the main board that there appear to be some factory repairs/touch-ups right around where the cable from the switching board connects to the main board, so it's possible that even at the factory, it was a bit suspect.  These guys aren't TB, and so far the schematics I've dug up are tough to zoom in on.   Anybody happen to know what components are involved in the switching scheme on these guys?  There is a tranny (haven't gotten the markings off it yet) directly in the switching path that could be a culprit.

I have a couple vactrols that I think I got from Smallbear a year or more ago that have no markings and I don't remember specifically which ones I might have ordered at that time.  The only marking they have on them is a gold 'F' on one side.  If that F doesn't mean something, is there some other way I can guesstimate what they are based on measuring resistance and matching up data sheets or something?