Thanks again for looking at this!

The NTC meassures very low ohm, in circuit it’s around 14 ohm.

The markings on the “receiver” board are: +27v, gnd, -27v and “mute”.

I would like to try to do some “divide and conquer” debugging, as the total number of components is rather low. I would like to try to eliminate the different “blocks”. Like I can connect it up, and measure the voltage after certain “stages”. Maybe after the inrush current limiter? To my very limited understanding that should be right at the end of the AC block/stage? Maybe dividing the board into 3 or 4 stages like this I could start to narrow down the issue?

I am guessing the MOV is the component marked MOV on the board, its markings are: TVR 07471. Can I test this "in-circuit, or must I de-solder it to test it?

In-Circuit I measure around 470kohm

Thank you for taking the time to help out :-)

I have attached a couple of images. I figured the PSU is the issue, since there is 0v between the black lead and the other leads on the connector to the other parts - the one in the bottom right corner on the attached overhead.

I measured the “MF 72 10D13” for connection, and it is OK. I then measured the two large capacitors (in-circuit) and they both come out fairly close to the 390uF they are rated as. I also tried to measure what I think are 4 transistors attached to the heatsinks. But am uncertain of the results there, as I can’t follow enough of the circuit to understand the results - and I am not even sure they are transistors - much less if they are npn or pnp :-) They are marked as Q1, Q2, D6 and D7 on the board.

When visually inspecting the board and components, the only thing I thought, might be “odd” was the “browning/darkening” around the circuitry near where “R1” is located.