Fiery Red Horse Bypass issue

[gordo]

This is a bit of a head scratcher.  I build the switch and main board.  The switchboard switches the LED but not the relay.  I swapped relays in case I got a bad one, no improvement.  If I put jumper loops in place of the relay the main board works (and sounds really good btw).  I've replaced the LPxxxx voltage reg with a standard 5 volt.  I've checked all my values for resistors and caps.  Solder traces are clean on both sides.  About the only thing I haven't replaced is the J175 (I assume that because the LED works the BS170 is good) but it should have nothing to do with the relay coil.  Is it a possibility that the PIC is pooped?  What should I measure across 3 & 6 when I engage the switch?  I'd be surprised if it's the PIC only because the LED switch portion is working but I suppose the code could be corrupt on the relay portion.  I'm getting proper voltages where I expect to find them.

?

[gordo]

I solved it.  Sort of.  It's fixed but I don't know what it was.  I ended up desoldering the electros, the BS170, the relay, and the PIC (I now consider myself to be ninja-level with the desoldering braid), and cleaned the board.  I put the PIC in one of the single board projects (socketed) and it worked so I left it there.  I tested all the parts that came out and all seemed fine.  I put in fresh electros and transistor, soldered in the old relay, and then used a low profile socket on the PIC.  That might make the board height a bit tight but I'll grind a damn hole in the enclosure if I have to.

Works like a champ.  I HATE fixes where you don't know what the fix was.  Who cares...it works.

[fair.child]

Based on my experience with debugging the VFE Switching board, tbh it's almost bulletproof switching. When I have an issue with the switching either the problem was my L2950 was 3.3V regulated or 5V regulated. It's easy to misplaced and misrecognized. The doc mentioned when the pedal is in bypass, it spits 5V pulse. When it starts getting switch signal, it will turn on to 0V and the BS170 acts as a switch. So your LED is on, then it means that you are getting the proper signal in and out from the PIC. If the coil doesn't start clicking at the beginning, there might be a cold solder joint or potential relay dud.

After building 32 VFE pedals so far (including the mega pedal build), I just only encountered one PIC dud/fail. Don't ask me why it fails because I have no idea.