18 Oct
2015
18 Oct
'15
9:59 a.m.
-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] 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
was
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
of
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
get
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
single
screw. Perhaps it was later decided that this was
insufficient to keep it
from
coming apart and exposing dangerous voltages if
dropped from a height and
it
was decided to glue it together instead?
I can sort of see why it might not be a priority to make the fuse
replacable.
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?
Regards
Rob