Well, I managed to fry my Ch 1 today when showing my nephew what happens when you put an electrolytic in the wrong way round.
PSU to 32V, 3A. 10V 100uF cap, wrong way around. Pop, magic smoke. But PSU starts saying it's overvoltage on Ch 1.
Then nothing, just a weak voltage slowly increasing, no error.
Took it apart just now, F5 was open circuit, replaced with 20mm 5A fuse soldered in. Back to the over voltage error - I measured it, about 50V - oops.
Took aim at the biggest transistor on that board, Q5, a CET CEP80N15. Pulled it off the board, all pins direct short to each other.
Had a look what else I had in stock as N Ch in TO220, all I could find was an IRF510, the Vgs looks alright, Vds a bit lower but the PSU won't be anywhere near 100V. On the negative side, the IRF510 is a mere wiper snapper at 5.6A continuous drain compared to the CEP80N15's 76A. But current isn't everything, it's power dissipation too, particularly in linear regulators like this. The IRF510 is still pretty bad at 43W compared to 300W for the CEP80N15.
Anyway, put it in and all seems hunky dory for now, until I get a proper replacement MOSFET that channel will be on emergency use only.
I am not sure if there is a hardware crowbar on this PSU. The programmed OVP and OCP still appear to function perfectly well, but I am not sure if that is a real crowbar or it just switches the transistor off. Either way, it is a bit of a nasty failure mode, 50V slapped right on the output.