CRT problem

From: Tom Uban <>
Date: Mon Jul 15 09:17:00 2002

Hi Dave,

I have a similar problem with a couple of CRTs from my Imlac graphics machine.
After doing some research, the I did locate a company which would rebuild the
CRT for something like $700, with no guarantee that they would not destroy the
tube. They also had expensive replacement tubes, which were not the correct

Another solution, which I haven't tried yet is to remove the CRT from it's
and soak the face in a bath of acetone for an extended period of time (or
until the
secondary lens is separated from the tube. Once separated, clean and reattach
using optic cement. This was suggested by a friend who repairs large antique
camera lenses. I'm not sure if acetone will dissolve the cement which holds the
lens to the tube, so a pre-test may be a good idea.

Some people have indicated a fear of removing the lens from the tube face
that the tube may well implode without it. I do not think that will be the
case, but
I suppose that it is possible. I believe that the lens is simply added
protect from
day to day use for the face of the tube and is not inherently required to
the strength of the tube against the vacuum inside. In any case, as always,
care should be taken to protect you, your eyes, etc. when handling CRTs, as
do carry the risk of implosion.


At 10:18 PM 7/15/2002 +1200, you wrote:
>I have a 10 or12 inch green screen CRT off an HP 9845B I need to clean up. .
>It has been stored in a damp environment and the silicon rubber 'bonding'
>the protective glass screen to the front of the CRT proper has developed
>large mould spots in side itself for an inch or two around the outside edge
>of the screen. I guess I am looking for suggestions as to how to readily
>separate theses two glass items without scratching etc so I can clean and
>rebond them. I thought at first there was a cavity between the glass on the
>CRT face and the protective glass out front- just a seal of silicon rubber
>round the edge- but no such luck-- seems like the silicon rubber stuff
>covers the whole area of the tube face- so I need to chemically remove it or
>Any ideas??
>The 9845B is running OK- getting a partial memory test failure at boot up
>but I don't expect that will be too hard to sort. Anyway-- that's next
>week's problem!
>Dave Brown
>Christchurch, NZ
Received on Mon Jul 15 2002 - 09:17:00 BST

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