iamrcb wrote:It turns out that the AUX jack was faulty. I tried to fix it but made it worse and the whole jack socket and solder pads came off!
Now my monotron doesn't have an AUX in. I'm either going to sell it as part working, as the synth is still ok and then get a replacement for £45, or try and wire in the jack to other parts of the circuit board and simply glue the jack socket back in place.
If you solder it back into place you need to not just solder the tip & ground, but also the other two connections that create a "switch" that enables the amp envelope when something is plugged into the aux plug.