Tektronix TDS 684A monitor having a really bad day

[magnehh]

Hey, guys! I finally got around to posting this. A few weeks ago, I was searching for old test equipment "trash" in the electronics waste bins, and found this beautiful beast of a scope. Took it with me, powered it up and WAH WAH WAH! 

As you can see from the attached pictures, the monitor is in some sort of gooey state. It looks sort of like silicone smudged out behind the front glass, but I have no idea how it would have gotten there.

Has anybody seen this before? Or do you have any idea of what it might be, and perhaps a fix for it? Any help is appreciated!

Magne

[tautech]

Welcome to the forum.

My guess is water under the screen protector overlay. 

Well you did say you got it out of a electronics waste bin......
 

[nctnico]

This is easy to fix but messy. There is silicone gel between the LCD shutter and the CRT screen. You can cut the assembly open and remove the gel. This guy wrote how to do that: http://jvgavila.com/tds524a.htm

[magnehh]

Wow nctnico, that's exactly what I was looking for! Thanks very much!

[Jwalling]

This is easy to fix but messy. There is silicone gel between the LCD shutter and the CRT screen. You can cut the assembly open and remove the gel. This guy wrote how to do that: http://jvgavila.com/tds524a.htm

Always wondered why Tek did this, in later models, there was no gel. It's like 5 ounces of gooey snot. After scraping most of the gel away with a plastic scraper, I've found that "Goo Gone" does a pretty good job of removing the remaining stuff.

[MosherIV]

My GUESS would be either crt shatter protection.
See this thread on similar note:
https://www.eevblog.com/forum/chat/vintage-crt-safety-lense-removal-and-cleaning/
I asked a colleague of mine at TNMOC.org and he thinks removing the bonding is a bad idea since you loose the protection but putting back proper glass bonded blast protection is a real problem.

Or could be extra protection from x-rays.

I am only speculating