4 Dec
2014
4 Dec
'14
2:27 p.m.
-----Original Message-----
From: Jarratt RMA [mailto:robert.jarratt at ntlworld.com]
Sent: 01 December 2014 21:19
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Random DEC Questions
On 1 December 2014 at 06:16, tony duell <ard at p850ug1.demon.co.uk> wrote:
I opened up the VT320 tonight. The PSU is set for 240V, which is good. However, I noticed
some corrosion around the flyback transformer. I have posted a picture here:
http://1drv.ms/1zqDhx5
This looks like corrosion of some kind of retaining clip perhaps, rather than anything
functional. Am I right, or should I be concerned?
Thanks
Rob
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 week.
Regards
Rob