OT: Stepdown convertor
ard at p850ug1.demon.co.uk
Mon Sep 18 17:14:46 CDT 2006
> I have been having problems with my Dreamcast
> (that I use to surf the 'net) resetting randomly.
> After checking out the power lines, it seems
> that the stepdown convertor is at fault. It
> has a crack and 2 bulging bits (where the
> plastic has been molded with lumps instead of
> flat) on the underside.
> How dangerous is this if it is the cause of
> the problem?
There are 3 basic types of these converters :
1) True isolating transformers. These are not common for this application
(and are almost never sold as comverters to run 110V stuff in Europe).
But IMHO they're the only truely safe solution _becasue_ the other types
all assume that the insulation of the connected device is safe at 230V.
It should be, but...
2) Autotransformers. A non-isolating transformer (one winding tapped at
the midpoint). This what you probably have.
3) An electronic triac-based circuit. Basically, a lamp dimmer fixed to
give the right RMS output. These are fine for running you travelling
clothes iron or other heating device, but are no good for electronic
stuff. In fact they will do a lot of damage (the peak voltage applied to
the laod is still 230V). I had to rebuild a Mac+ analogue board that had
suffeerd from one of these -- suffice it to say I had to replace most of
the trnasistors and capacitors in the mains side of the PSU.
> It converts a 240V input to a 110V output (not
> been able to check the exact specs on it, as
> it's in use and very hot), as my Dreamcast I
Now that worries me. A transformer should not be 'very hot'. Either it's
not designed for 50Hz working (umikely), or it's underrated for the
application. Do you have idea idea as to the power (VA) rating of the
transformer and the power you machine takes?
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