[Apfelmus]

Here is an update.

I tested the diode D870 with a higher voltage, it seems OK. Its probably several diodes in series, so the voltage drop in pass direction is something like 20V.

No measurable heating of the diode when running with everything connected.

I let the transformer run with open secondaries pin7/8, as suggested by John. It gave very distinctive whines, changing while heating up. Power consumptio of the whole unit remains the same, and the transformer heats up as fast as with the secondaries connected.

Attached is a picture of the transformer, and also an IR picture of it when the current limiter comes on. The parts with the brightes yellow are at 65°C.

If its a problem with the transformer, like temperature-dependent shorted windings, shoundn't the current increase appear rather suddenly and not as progressive?

cheers
Martin
Martin