Hi All,

I fired my Ansmann Energy 16, cell battery charger up earlier to
charge 4 x D NiMh's and initially it looked like it was behaving
normally but when I looked at it again a few minutes later, there were
no LEDs illuminated? ;-(

Checked the mains (3A) fuse and it was blown, so I removed the cells,
replaced the fuse, tried it again and it blew again.

I took it to bits, blew a bit of dust out of it and running the DMM
over it on low Ohms, it seems there is a fairly low resistance across
the AC input (~ 2 ohms).

https://www.dropbox.com/s/r93ghlg58qgcxhv/Ansmann%20PSU%20top.jpg?dl=0

https://www.dropbox.com/s/yx4vg5td3mqkiu2/Ansmann%20PSU%20bottom.jpg?dl=0

I then disconnected the PSU and (carefully) ran it up on the bench and
again, the fuse blew instantly (however, I'm not sure if it's ok to
run the PSU like that with no load etc)?

I de-soldered one end of both the input filter caps, and the first
transformer and the very low resistance went away on the input side
(so it wasn't a shorted cap) but was still across the board where the
txfmr output was. FWIW, of the 4 bridge rectifier diodes D1-4 in the
middle of the board, D2-3 test out ok in cct, D1,4 test as short cct.
All the other diodes and caps around that part of the circuit seem to
test out ok on the DMM (diode test, cap continuity charge 'beep' upon
probe connection) so I was wondering if someone could point me in the
right direction re checking it out further etc please?

Given there isn't much else on that board, is it likely it's the first
txfmr, one (or both) of the TOP223Y's (PWM switch) and how could I
test them if it was please? Or could it be the (PC817) opto-isolators
as I assume they would be fairly easy to test out of the board?

Thanks for your help in advance ... ;-)

Cheers, T i m

p.s. I might have got some of the above wrong so please assume that to
be the case as I don't want to mislead anyone. ;-(