On 02/02/18 19:56, Johnny B Good wrote:
[1] or, if you're very lucky, a shorted bridge rectifier diode.


That seems virtually certain.

[2] I may know the basics but most of the drive and control circuitry in
modern day SMPSUs will be integrated into a custom controller chip or two
which would need to be identified and a data sheet tracked down before
one can even begin to think about attempting to diagnose and repair such
a unit. Unless it's truly impossible to substitute the failed SMPSU with
another off-the-shelf unit, it's normally much cheaper to replace rather
than repair an existing one.

No: By and large the chips don't blow, There is usually a chopper power
MOSFET and that is what takes the strain if a diode goes bad.

Replace diode, 450V cap and power FET and fuse and it should work




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