Extech 382260 Fault

[tgdavies]

I have an Extech 382260 bench power supply. I have not used it much, but it has worked fine.

Last night I had it set to 12V 1A and was powering a LiPo battery charger which was drawing about 800mA. Suddenly the charger turned off, and I saw that the power supply was providing about 4V at 10mA.

Turning the output of the PS off and on turns the charger on for a moment until the overcurrent cuts the voltage again, so it can supply the current.

Turning the output off, holding down 'review' and turning the 'current' knob does nothing -- the set current fluctuates between about 5 and 20 mA.

I've tried unplugging the PS and using different ranges.

The charger is fine -- I'm now using it from a wall wart which provides 12V at max. 1A and it's charging a 2S LiPo at 1A.

Any ideas about what might be wrong, or what else I can try.

Thanks,
  Tom