Hi Microsolar,
I believe you are on the right track.
Indeed I would think you have a DC problem.
Check out the FET's on the DC side for shorts (multimeter set to ohms)
On my working unit I get: infinite resistance in one direction, and around 6Megaohms in the other direction).
Measured from center pin to the left pin and from center to the right pin (and from right to center, left to center)
It's no problem to measure them in-circuit.
Power consumption should be very low, when powered from a 6V power supply: on my unit it is around 10mA.
I believe pin14 of IC2 does not get much voltage because everything is going trough one(?) shorted DC FET.
Pin 18 of IC2 is used to sense the startup and shut off voltage (10,5V and ...28V) into the microcontroller. It is via 2 resistors connected to the + (after the power switch)
The programming connector on my unit is also labeled J6.
Cool: the 5 pin connector is already installed on your unit!
I had to solder in the pin's myself.
If you can get the unit working I would be very curious to see if you can extract the code from the PIC. Mine appears code protected.