New DEC museum entry :D (not the breaker sub-thread)

[Patrick Finnegan]

On Thursday 22 February 2007 18:25, Adrian Graham wrote:
> On 22/2/07 19:39, "Tony Duell" <ard at p850ug1.demon.co.uk> wrote:
> >> I think it's gotta be a ground-fault that's causing Witchy's
> >> problems.
> >
> > I am almost sure it is.
>
> Well, tonight I stripped the PSU down and there aren't any filtering
> caps, at least not the X type ones I'm familiar with. Instead the
> mains cable plugs into a honking big sealed tin box that terminates in
> a 2 inch earth wire and 2 spade connectors that the live and neutral
> hook up to. Said earth wire is bolted to the chassis and joined to a
> similar bolt holding the fan to the case.
>
> Anyone seen something like this 'mains plug in a sealed tin box'
> arrangement before?

Yeah, it's a sealed (and probably potted) power-line EMI filter.  It 
should have some filter caps and coils in it.

Assuming the extra power-line noise you get by removing the EMI filter 
isn't a problem, that's probably something that you can try bypassing, 
to see if it's the source of your problem.

Pat
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