14 May
2013
14 May
'13
1:44 p.m.
Quoting Philip Pemberton <classiccmp at philpem.me.uk>:
How easy thst is depends on the design of the input stage of the PSU.
PSUs that are designed to run at either mains votlage with simple-ish
conversions run the chopper circuti from 350V or so. For 110V mains,
that's got by votlage-doubling the mains, for 230V mains by simply
full-wave (bridge) rectifying it. In amny cases, 4 diodes are fitted all
the time, it's just a matter of cuttign a link to convert from 115V input
to 230V input.
However, I have seen a few SMPSUs that were designed for 110V mains only.
They ran the chopper fof a 170V (or so) supply, obtained by full-wave
rectifying the 110V mains input. THere is no easy way to get that votlage
straight from 230V mains.
The qucij way to see if a conversion is going to be easy is to look at
the mains smoothing capacitors. If there ar 2, of equal value, with the
-ve side of one linked to the +ve side of the other, then it's very
likely to be a votlage doubler circuit and thus easy to convert.
Perhaps the OP can check this in his PSU.
-tony
The problem is that it has a 400W power supply...
the largest
autotransformer I can get locally is a rather nasty 300VA cheapie. :(
Did you try to post on comp.sys.3b1?
Probably somebody there would know how to convert the 110v to a 220v
power supply ...