[jan-jaap]

I found some original NOS Motorola 2N6678 transistors :-)



On the bench it can supply 40A with sense feedback from the load to the PSU, without oscillation or strange noises.



Here's why I don't like blind component swaps in something like this. There's half a dozen undocumented adjustment points here for the 5V output alone, not counting the V1 ADJ. if I start replacing components I'll almost certainly have to recalibrate it. Without schematics or a service manual that's a no-go.



Fingers crossed it still behaves when I put it back in the system.