ebay power supply

[ecat]

thank you anyway.

An older part perhaps? There is certainly enough info on the, what I suspect to me similar, ucc2884, 3884.

If I can track down a comparator feeding the opto-isolators then the switching chip may be irrelevant. You mention a second opto, could this be for over-voltage?

Output -> voltage divider -> comparator -> opto... if nothing else the feedback circuit could be replaced.... heh... maybe :)

Guessing again, the comparator - in custom chip or not - is running from +5v or +12v, so there must (-ish) be a voltage divider external to the custom chip/comparator etc.

Anyway, we know these are good for 42v.
Drivers that can cope with the full 56v are not so expensive (?)
On a personal note, if the worst comes to the worst, I now have the makings of +/-56v psu @ 500w which will make for a stonking sub-base amp :)