Help with ICL power supply fault (Farnell SMPS)

Peter Coghlan pcoghlan+cctech at
Fri Apr 11 04:39:38 CDT 2008

>One way to achieve isolation is to get a couple of filament transformers that 
>are of similar voltage ratings and use them both,  tying both low-voltage 
>windings together and using one primary as the output.  I'd think that they 
>wouldn't need to be particularly hefty if you're not going to load the supply 

Another approach I keep meaning to try out, also for small loads, is a
bathroom shaver outlet isolating transformer. Many, like the one in my
junk box, also have the advantage of providing a choice of output voltages
so that equipment designed for the other side of the Atlantic only can
also be tested.

(I last thought of this approach just after I blew the input fuse in
a small SMPSU after somehow managing to confuse myself about which were
the input rectifiers and which were the output rectifiers. But it was
too late then so I didn't bother...)

One thing that puts me off though is that I vaguely remember reading a
report from someone who had a SMPSU that behaved even more bizarrely than
these things usually do when it was powered through a less than ideal
isolating transformer.


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