I have checked all of my joints, and while some are a little ahem enthusiastically soldered, there don’t seem to be any unwanted solder bridges. It does occasionally make a noise when engaged, if I am not grounding the circuit, there is a high-pitched hum that pulses with the rate of the tremolo. Still no signal from the guitar though.
How would I check with my multimeter if there are shorts between the IC pins? I am using the insulation paper.