Here's a somewhat beat looking example of one of those Sony Combos.

Looks like the tube is getting bubbles around the edge.

I don't think I've seen a Sony before with this problem.

Are they a bonded tube?

http://cgi.ebay.com/1975-Sony-Trinitron-with-very-first-betamax_W0QQitemZ300305213895QQcmdZViewItemQQptZVC Rs?hash=item300305213895&_trksid=p3286.c0.m14&_trkparms=66%3A2|65%3A10|39%3A1|240%3A1309

I had a late '70's 19" Sony with a similar problem. The set had many problems and I tossed it.

All of the '60s-early '80s Sonys had a bonded tube, but it's rare to see a cataract. It may have been in the sun too long, or in other unfavorable elements. I've seen a few of them with those black bubbles, and it's usually ones stored outdoors (or been in a fire).

It's the same tube as all the other 19" Trinitrons from '73 through '78.

Charles

I heard people call this "screen rot". I've usually seen this happen to old computer terminal's after they've been stored in a humit garage for a long time.

Like these:
http://www.dvq.com/oldcomp/photos2/1k/adm3a_1.jpg
http://sturgeon.cac.psu.edu/~mloewen/Oldtech/Terminals/HP2647A-1L.jpg

All of the '60s-early '80s Sonys had a bonded tube

We never had a trinitron CRT with a bonded safety glass here in Europe, maybe it was a legal requirement in the US back then?