22 Feb
2007
22 Feb
'07
6:15 p.m.
On 22/2/07 19:39, "Tony Duell" <ard at p850ug1.demon.co.uk> wrote:
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
Oh yes. That sounds like a mains filter unit. Inside there are several
capacitors and inductors. If you're very lucky there'll be a schematic
printed on the can somewhere.
I think
it's gotta be a ground-fault that's causing Witchy's problems.
I am almost sure it is. before? The thing's got to be 4 or 5 inches by 2.5
inches so whatever goes
on in there is anyone's guess. If I was at work I may be tempted to unhook
the earth wire that's bolted to the chassis but it's there for a
reason....though normally I'd expect that to be there to ensure the psu
casing was never live.
IOt may not do you any good to do that. Often the can is connected to the
mains earth anyway, the wire is just there for a 'belt and braces' aproach.
What I would do as a temporary measure is to remove that filter can
altoghter and wire a mains cable (or IEC plug) with earth to the PSU
chassis and live/neutral to the 2 spade terminals (this leaves the
breaker in-circuit, right? I don't have a Pro in front of me at the
moment, I can dig one out if need be). See if the machine still trips the
mains.
-tony