Zhaoxin CVCC 60V 50A bench supply KXN-6050D

[najrao]

 Looking for a easy-to-use high power unit for testing motors, I scored this  rather elderly  PRC? made bench  switcher ps for a few dollars. Opening the cover revealed that I was the first one in. Of course it does not work.

Went through variac and dim bulb start up, it draws only a small current direct on mains (230V). The inrush stopper relay ticks as it should. The auxiliary supply comes up, and turns on the fan (Only to shut it down, said to be thermo controlled); the display lights up all digits, voltage climbs slowly to an indeterminate 10 or 12V, only to collapse equally slowly to zero. CC and OVP settings have no effect. After the first flareup, the CV knob too does nothing further.

I found that the CC pot was completely OPEN between each two pins, and have substituted it. Nothing changed for this, except that the CC LED no longer lit up as used to.

It has only a two-layer board and all through-hole soldered components. But the IC faces are sanded off, and disassembly of even the connectors is a royal PITA.

I am hoping someone with such switcher has seen this model before and would kindly advise me on how to proceed.

Edit:  I have now fully restored this animal. Reported for providing closure to topic.