Ibanez Tone Lok switching

[slacker775]

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.

[wgc]

Fet switch?

[slacker775]

Yeah, there is an IC (TC74HC04AP) that looks to be basically a 4x switch as well as a 2SC1815GR tranny that may be involved in the switching.  Seeing that I can get a replacement switch at SB for under $1, I may try that just to be certain.  I did find that there is a trimmer that appears to set the voltage going to the IC which was reading about 4.39V which I was able to get up to a solid 4.5V but that didn't seem to make much difference.

[thesmokingman]

does the little switch itself work flawlessly each time? if so you'll need to improve how the treadle engages the switch. I've had that issue with one of the tone lok pedals in the past.

[slacker775]

Connecting the dmm to the points on the main board where the leads from the switch connect and manually triggering the switch with my finger gave a solid 'beep' every time.  That's where I wonder if perhaps voltages are off a bit and thus not triggering the 'flip'.  There are some ceramic caps in the mix, that perhaps aren't working as they should.   As I recall, there is at least one ceramic that's definitely right in the neighborhood for switching that shows evidence of having been replaced, and one electrolytic that I think it's outside the area but I can double check its connectivity on the schematic.