Opening a DECserver 90M External PSU

Robert Jarratt robert.jarratt at
Sun Oct 18 11:59:34 CDT 2015

> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at] On Behalf Of Peter
> Coghlan
> Sent: 16 October 2015 23:45
> To: General Discussion: On-Topic and Off-Topic Posts
> Subject: RE: Opening a DECserver 90M External PSU
> >
> > Thanks very much for this. Interesting that there is a fuse inside.
> > You would think the casing would be designed to allow the fuse to be
> > replaced somehow.
> >
> That's not the original fuse either.  I managed to blow that one when I
> trying to find the original problem with the PSU.  I was having a really
bad day
> and I somehow managed to clip the scope ground lead onto the negative end
> the rectified mains smoother instead of the negative of one of the output
> smoothers.
> The original fuse had wire ended caps pressed on to it and I was unable to
> them off so I ended up soldering loops of wire around the replacement fuse
> instead.
> It looks like the case was originally designed to be held together with a
> screw.  Perhaps it was later decided that this was insufficient to keep it
> coming apart and exposing dangerous voltages if dropped from a height and
> was decided to glue it together instead?
> I can sort of see why it might not be a priority to make the fuse
> Firstly, someone might try to replace it with a 13A plug fuse.  Secondly,
if the
> fuse did blow, there would likely be other components damaged.  Sadly, it
> might be cheaper to get a replacement unit from stock than to pay someone
> capable of repairing it properly and ensuring it's safety afterwards.
> Regards,
> Peter Coghlan.

I had another go today, but I fail to see how you managed to pry this thing
apart without causing much more damage than appears in your photo. What kind
of tool did you use?



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