Playing with HP2640B

[Rik Bos]

I did it by heating the crt to about 50-60 degrees celsius and used a putty-knife.
https://www.flickr.com/photos/hp-fix/albums/72157689357633754
The photos are from a Philips P2000M system but I did it the same way with my 264X terminals and 9845's systems.
It takes about half an hour to heat and separate the screen from the crt .

-Rik

> The screen on my HP2640 had degenerated quite far. It was only a spot in the
> middle, 2 by 4 inch, that still attached the glass to the CRT. I used a thin fish fillet
> knife to dig through the remaining glue.
> 
> Before
> 
> https://scontent-arn2-1.xx.fbcdn.net/v/t1.0-
> 9/23622163_10155696765784985_6518064439030378363_n.jpg?oh=44cbf7f7f
> 00d6e25155c208124e20a38&oe=5AA7349D
> 
> The result after:
> 
> https://scontent-arn2-1.xx.fbcdn.net/v/t1.0-
> 9/23621971_10155696757184985_1959733265676657917_n.jpg?oh=36a20689
> c0fb5a16de7fc4df138a40e0&oe=5A9993B1
> 
> 
> Anyhow, I researched the glue a bit. The glue is, as far as I understand, PVAc
> (PolyVinylAcetate, sometimes also known as PVA). PVAc is not soluble in water.
> It takes quite high temperature to melt it. However PVAc is soluble in many
> esters. I bought some Butylacetate. It dissolves sample bits of glue from HP2640
> quite well and rapidly. Butylacetate has quite high boiling temperature (about
> 120 degrees centigrade) and thus does not evaporate that quickly. So my idea is
> now to test on a 2645 screen or VR201 screen by adding some butylacetate and
> seal with some thin plastic wrap foil and let it dissolve a bit. Then use the fish
> fillet knife again and repeat the process.
> 
> /Mattis