MK139 clap switch

Hello everyone,

I recently assembled a mk139 with a friend of mine. At first it didn’t work and broke the diode. After careful study I found a fault in the PCB, the second point of the diode was making a short (in the PCB, not solder). After carefully scratching it out the switch worked as intended.

Now I was going to make the onboard relay use the 12 volts to switch a heavyer relay to work with 240 volts. The idea was to use the 12 volts from the PCB points next to the power plug on it. On testing it didn’t work and after measuring on the poles I get 0,04 volts on the poles. When I disconnect the plug and measure that I get 12,46 volts but as soon as I plug it in, and the mk139 works normally, I measure 0,04 volt directly on the poles when the plug is plugged into. The mk139 is rated 150 mAh and the supply is 300 mAh.

Who is stealing my volts? :frowning:
could this still be a short somewhere ?

You should post some clear pictures of the top and bottom and put the link up here

as you can see I’ve soldered a tiny wire from the positive to the diode, because the etched copper went bad when the diode burned out when in shorted on the other end, where you can see the scratching around the solder point.

I had to download the pictures but when I zoom in they get very fuzzy

That should be a much larger version