23 Mar
2004
23 Mar
'04
5:58 a.m.
-----Original Message-----
From: cctalk-bounces(a)classiccmp.org
[mailto:cctalk-bounces@classiccmp.org] On Behalf Of Paul Koning
Sent: 23 March 2004 19:37
To: cctalk(a)classiccmp.org
Subject: Re: More on my flickering DEC monitor
I'd say either those components shown in solderside.jpg were
replaced at some point, or the person doing the
hand-soldering wasn't particularly competent. More likely
the latter since the signs are there at every pin that's a
hand-soldered part, as far as I can see.
It could be; I rescued the monitor from the dumpster queue after the
previous user had complained that 'the colours were all fuzzy'. A quick
adjustment of the Purity control sorted that out :)
It's possible it's been repaired in the past too.
Look at D910 (a bit further to the right on that
photo) for
an example of good work. (I think that one is the wave
solder machine at work...)
'K
normal use. Raising them -- and high current diodes
like
D907 -- off the board is a typical trick to get better
cooling. The radiated heat tends to discolor the board at
some point, that isn't necessarily an issue.
Right - that makes sense.....
Something to look at, though: on the
"solder.jpg" picture I
wonder about the funny rings on the right solder joint of
R923 and R924.
That may just be a shadow, or it may be a mechanical problem
in that joint. It wouldn't hurt to find joints like that and
re-melt them.
It's not shadow, that's what made me ask in the first place....I've now
remade all the large joints like that and I'm in the process of putting the
whole shebang back together.
Ta! If you hear a bang in the next half hour you'll know what it is.....
--
Adrian/Witchy
Owner & Webmaster, Binary Dinosaurs
www.binarydinosaurs.co.uk - possibly the UK's biggest online computer museum
www.snakebiteandblack.co.uk - ex-monthly gothic shenanigans :o(