Hi guys,
Relatively new here - but been messing about building guitars and simple effects (Germanium Fuzz Faces / treble boosts etc.) for years, and only just started to look at more challenging (for me!) effects builds.
Go easy on me - I don't really understand much about what I am doing electronics-wise - I can just about cope with discrete components - but this is my first foray into anything involving ICs.

I have just finished putting together the tri-vibe - on a board I etched myself - but am having some "fun" trying to debug it.
I have triple checked all connections / tracks for shorts etc all electrolytic caps and diodes are correctly orientated - so can I now ask for some assistance from you electronics Gurus on here.
Symptoms:
Nothing at all audible with switch in central "vibe" position.
Clean audio getting thru on other two settings - but with no (or extremely subtle) vibe. Pots have no effect.
I am using a lin 10k pot for depth and a normal log 500k pot for rate with lugs 1 and 3 reversed as I can't easily find a C taper version - I am in the UK
I am using TL064CN, LM13700N, and NE5532P
Voltages on pins of U1-U3 seem mostly to be in the ball park with switch in vibe position and both pots about halfway - and I can list voltages if needs be.
Some of the voltages are a little hard to pin down as they fluctuate - I assume that is because they are supposed to?
However, pins 10 and 12 of the LM13700 seem low at 0.6V?
Any ideas?
Only component I was a little unsure of was the red LED - I used what I believe was a "normal" 5mm red led - not a superbright or high intensity one - is this critical.
Thanks in advance.
FF