Strange Spots on Trinitron CRT

[jhalphen]

Good day to all,

Photographed this strange spot structure (see photos) on an early 80s Sony French Trinitron color TV - model KV-1810DF an 18 inch model. TV belongs to a friend.

No, the CRT is not dirty. If it was a Roundie, i would say "Cataract" but to my kowledge this Sony CRT has no plastic protection screen and viewing is straight through the glass. The CRT is still under vacuum, so he says, i didn't check.

Nope, it's not paint. I took the pictures and ran a finger over the glass: it was smooth with no asperity.

Anyone seen this symptom before?

Just curious about the mechanics of degradation. Obviously if inside on the front of the phosphor layer, there is no cure.

Best Regards

jhalphen
Paris/France

[lnx64]

Definitely looks like an adhesive that is rotting..

Matter of fact, looks just like Laser Rot that you see on some optical discs.

[lnx64]

PS that's not on the phosphor layer. It's leaving a shadow on the phosphors, and is also on the black area of the CRT.

[crtfool]

I would also have to say that it is Sony's version of a cataract - adhesive rot - look at the discoloration on the 4 corners of the screen.

Also, it looks like MOLD - has this TV been stored in a very damp environment?

[Sandy G]

It's got the Measles !

[DaveWM]

looks like mold to me.

[AiboPet]

Wonder if those Trinitron tubes have a plastic laminate over the front. I have no big Trinitron CRT to look REAL closely at on the edges. I have a 5" Trinitron (5200) that doesn't appear to have anything like this yet.....and none of the old Sony sets (8-301, 5-303,305,307...or the 700U sets) have anything like this on their b/w tubes either.

If it's laminated, I'm pretty sure you won't be able to find the edge without having the CRT out. I'd be curious if you can remove a simple laminate like car window tint....and STEAM it off with a garment steamer. I had to recently pull tint off two front windows of one of my cars (DAMN CALIFORNIA!)...and couldn't believe how easy it was with steam applied as I slowly just pulled it off in ONE piece.

[colorfixer]

I've seen green halo on the 19" tubes used in the LV-1901. I'm sure that there is some form of bonding on these tubes. Maybe KX250 can confirm?

[andy]

...

[RobtWB]

odd to see on a Sony set
I have a 67 Zenith rectangle crt that has the same looking "mold" spots as I see on your Sony set - always assumed aging of the pva between safety glass and crt face

[wa2ise]

Older American color CRTs the faceplate is stuck on with a silicon like glue. And can be removed by various techniques, search this forum for "cataract". Though none were like Sony's.

If you remove the CRT from the cabinet, don't take the yoke and other stuff attached to the neck area off the CRT, as that will require you do a convergence over again, and that is a PITA.

Be sure to wear eye protection, as CRTs can be dangerous if they implode. A full face shield would be better. And long sleeves and full length pants too, idea is to keep flying bits of glass out of the skin and eyes.

[jhalphen]

Good day to all,

Thank you! gentlemen for your replies. I've learned something: that Sony also used a plexiglas protection faceplate on some of its tubes - never suspected that.

TV belongs to a friend so i won't be attempting removal.

Best Regards

jhalphen
Paris/France

[ChrisW6ATV]

Originally Posted by andy

It's a cataract. Sony used bonded safety glass on some CRTs until the early 80's.

Yes, I have seen Sony CRTs with faceplates, too, but none (until now) with a "cataract".

[freakaftr8]

Really interesting. I have seen a sony 15" before with a hint of green on the top of the screen. Now I know what it is.

[kx250rider]

I've seen cataracts on Sonys; mainly 26" and a few 21". Usually those had been in fires or been out in the sun for a long time.

Charles