Sorry, when I say overload I mean that the voltage won't go
Any higher and the 'current mode' led comes on. If I watch the meter om mA, it swings all the way up to 500 mA like a short.
Thanks!
Then you should;
Check voltage across C6. Is it about 12.6 volts? We need to make sure always the reference is correct.
Let make sure R12 potential meter is OK, so you should measure the wiper voltage with respect to the board marked as 12, as you turn the potential meter, the voltage varies on the wiper;
Edit: you can also measure the wiper ohms without power on, objective is to check function of potential meter.
then Measure U1;
Pin 5 with respect to Pin 11;
Pin 6 with respect to Pin 11;
Edit: Pin 7 with respect to Pin 11;
Edit: the silly thing about this design is that it exposes the U1 inverter input Pin 5 to external connection RC unprotected.