In message . com, Jules
writes
On Fri, 18 Sep 2009 13:27:48 +0100, Fred Bloggs wrote:
There's no primary-side switching transistor, which is unusual.

I thought that, too. It is off-board somewhere, or soldered onto the
reverse side of the PCB (which would also be unusual)?
There is, it's in the ST Viper Chip, it's pretty much all the control
gear and power bits for a small SMPSU. I'd replace the chip, the diodes
D1-4 and check the rest of the diodes, primary and secondary.

Jules


--
Clint Sharp