From: "red rover"
Subject: Re: Strange failure mode in switchmode power supplies: Followup
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
Date: Sat, 21 Sep 2002 17:19:57 -0400
NNTP-Posting-Date: Sat, 21 Sep 2002 17:15:17 EDT
Organization: Bell Sympatico
I thought the UK homes
were fed by coax power feeds. I'm not sure I follow
your description. Is this transformer a Delta-Y transformer?
Is there an online diagram?
At any rate, is it possible the OP is being subjected to high
AC magnetic fields? Maybe from a buried transformer or such?
"Tony Williams" wrote in message
> In article ,
> Peter Gutmann wrote:
> > A few months back I posted a message about strange failures
> > in assorted switchmode power supplies in computers, printers,
> > routers, etc etc. Various people offered suggestions, and
> > I've been trying those out (along with anything else I can
> > think of) to try and find the cause of the problem.
> > - Check for wiring problems (eg ground & neutral reversed, nothing)
> [snip list]
> It still feels like there is an impedance in series
> with the supply. Is there any other house nearby
> that is fed off the same transformer,and do they have
> a similar problem?
> Is the stepdown transformer like in the UK? A 3-wire
> hv supply, down to a 4-wire star-connected secondary,
> 240V Line-Neutral, which is your incoming mains.
> Does that transformer have a Neutral fault... resistive
> or not connected. That would give you crazy mains,
> because the Neutral would be wandering around, varying
> even with whatever load is on the *other* two phases.
> Have you checked the Neutral-Earth voltage at varying
> loads, and generally during the day?
> Tony Williams.