Mk171 voice changer. no power

hi, i have just completed the voice changer kit, but do not seem to be getting any life out of it. the led’s no not light up, but some crackling is heard through the speaker. i have tried to maintain proper polarity (although mistakes can be made). has anyone else had a problem like this, or advise? many thanks

Can be anything but most likely assembly problem.
Check solder joints, part values and orientation etc…
Pay attention to microphone connection and IC direction.

hi, the mine worked well at the first test; and it’s still working! some cracks if the signal input is too high, but easely fixable. (i put a jack input and removed the mic…). i also removed some resistance for some trimmers and the result is extra!

Checked all tips and troubleshooting pages but still no success so… what now?