Playing with HP2640B

Mattis Lind mattislind at
Fri Nov 17 04:52:47 CST 2017

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.


The result after:

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.


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