7 May
2010
7 May
'10
12:37 p.m.
On Fri, May 7, 2010 at 4:09 AM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
yes a switcher, more pictures here including the exploded/over-stressed
metallised polyester capacitor, which was across the mains:
Ah, an antisocial mains filter capacitor. It happens...
IIRC there are several classes of such capacitors. One type is designed
to go across the mains, the otehr type (which cannot fail shorted) is
designed to go from one side of the mains to ground. I think they're 'X'
and 'Y2' respectively. But you need ot check.
Remember it's the AC voltage rating that matters. A capacitor rated at
250V DC sill not stand European mains.
(Aside:
on powerup it promptly had conniptions and also needs parts for
the
PSU - fortunately easy to find at our local
electronics store).
What fialed? Isn't this a swticher? If the chopper transistor has failed
(and it did in a couple of VT100s here),, you need to check surrounding
components (particularly low-value resisotrs) too.
http://picasaweb.google.com.au/109027456703228169358/20100504DECGIGI#
someone on IRC mentioned that this Aztec PSU is very similar to the one in
the Apple ///
SMPSUs tend to be bought-in, and similar designs turn up in various
manufactueres products. Even when the supply was a custom design, often
the circuitry is similar in various models (for example the Boschert PSU
used in some HP mass storage units is electronically very similar ot the
Boschert PSU used in the HP120)
-tony