29 Jan
2024
29 Jan
'24
9:54 a.m.
There are several YT videos as you mentioned. Definitive is in the eye of the beholder, I
think. In hindsight, I would remind people to keep their cool and carefully think through
the safety procedures related to CRTs before starting any work. I totally forgot to
discharge my CRT but I got away with it (I guess because it had not been powered on for
four months). An interesting side note is that the anode cap on the leaking CRT had gone
rock hard and there was a small "streak" on the back of the CRT that looked like
the plastic that it was made of had released some sort of oil. Maybe it was attacked by
something outgassing from the goo that the CRT was dripping. Anyway, like Wile E Coyote,
after I had shoved a screwdriver under the uncooperative anode cap and finally gotten it
off, I suddenly thought "What the HE** did I just do???".
Bill S.
-----Original Message-----
From: Bill Degnan via cctalk [mailto:cctalk@classiccmp.org]
Sent: Monday, January 29, 2024 12:16 PM
To: General Discussion: On-Topic and Off-Topic Posts <cctalk(a)classiccmp.org>
Cc: Bill Degnan <billdegnan(a)gmail.com>
Subject: [cctalk] Re: ADM3a screen rot.
Is there a definitive guide for repairing screen rot. One of mine needs it. I have
watched others but I have not attempted my own. I might try this at the Kennett Classic
workshop this upcoming Feb 17th Bill
On Mon, Jan 29, 2024 at 11:41 AM William Sudbrink via cctalk <
cctalk(a)classiccmp.org> wrote:
A quick note on ADM3a screen rot... my vintage
collection resides in a
cool
(60-72 degrees F) dry basement. My "pride and joy" ADM3a (I have
several) was just starting to show a few bubbles at the corners last
September. I was pulling out some parts units on Friday and noticed
that one had a much better screen than I remembered. Thinking that I
might swap screens, I took a close look at "PnJ" and discovered to my
horror that most of the lower half of the screen had "melted".
"PnJ"
was on a shelf, below eye level, nowhere near a vent or other source
of heat. I was so annoyed that I immediately started cleaning/repair
without taking any pictures (sorry).
Fortunately, there does not appear to be any corrosion from the "goo".
I completely desoldered and removed the keyboard assembly to get all
of the crud out of (and out from under) it. The mainboard is a fully
socketed example and the crud is down in several of the sockets. I'm
still working on that. Anyway, the take away is don't assume (like I
did) that the ruined ADM3as you see are the result of temperature
extremes. It can happen anywhere. Keep a close eye on yours if you
have one.
Bill S.
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