17 Nov
2004
17 Nov
'04
10:56 a.m.
Actually, these caps usually don't fail in equipment that's powered up
for long periods.
They fail after being unused for a long time and then returned to service.
----- Original Message -----
From: "Peter Brown" <peterbrown10(a)hotmail.com>
To: <cctalk(a)classiccmp.org>
Sent: Wednesday, November 17, 2004 1:35 PM
Subject: Re: HP 2113B service manual / schematics
Hi Joe,
One of the things that I noticed was that the
computer kept running and
even though I turned >off the power switch the cap kept sizzling.
On the 2113 (and I guess from your description the 2117) the capacitor is
directly across the terminals on the mains input socket - i.e. on the
'always hot' side of the on/off switch. So turning the power off behind
the front panel of the computer won't help.
In order to effectively control interference the capacitor has to be
mounted as close to the point at which mains enters the equipment
enclosure as possible. Mounting it further away causes the input leads to
act like an antenna inside the enclosure.
I had to unplug the line cord to stop it.
Yep, this is the only way to shut the power off to this capacitor, it is
always live when the equipment is plugged into a live mains socket.
A good reason NOT to leave this sort of equipment plugged in but turned
off!
Peter Brown