Random DEC Questions

Jarratt RMA robert.jarratt at ntlworld.com
Mon Dec 1 15:19:05 CST 2014

On 1 December 2014 at 06:16, tony duell <ard at p850ug1.demon.co.uk> wrote:

> > Not sure what makes it an international model, although it does say
> 50-60Hz,
> > and it does not have a captive power cord, so presumably it is an
> > international one. I will have to take a look inside, but I really don't
> > have any idea what I would need to do to convert it.
> Nothing specific to the VT3xx
> Normally SMPSUs that can be converted to run off 115V or 230V
> mains run the chopper off about 350V DC. The mains input
> rectifier circuit is configured to be a simple bridge rectifier
> for 230V and a voltage doubler for 115V. The conversion is
> nothing more than a link from the neutral side of the mains
> to the centre tap of a pair of smoothing capacitors in series
> (if you look at the circuit, you end up with 2 diodes that are
> redundant, always reverse-biased, in the voltage doubler
> circuit, but that is no problem).
> So look for a link on the PSU board in this area. If you are
> lucky it will either have 2 positions labelled '115V' and
> '230V' (in the latter position it actually does nothing) or
> will be marked 'fit for 115V' or something.
> -tony

Thanks for the suggestions from Glen and Tony. I am away from home most of
the week, but I will take a look when I get home again at the end of the



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