KV-1800UB barn find

[Mark Hennessy]

It's hard to be exactly sure because the camera shakes a bit and focus sometimes hunts, but I still think that at least some of it is on the surface. Or at least, not in the same plane as the phosphors - without being there, it's impossible to be sure (some more marks on the face would help). And yes, I can't help wondering if at least some of what we're seeing on the phosphors is actually a shadow caused by the marks on the surface.

So what do we know about the construction of these? Is there a chance they could be made from laminated glass? Some CRTs were. The fact it's migrating in from the outside edges would support that.

I don't think it's anything on the aperture grille, as you can't see that through the phosphors (disclaimer: I'm assuming the set wasn't powered during that video).

[djrm]

Greetings,
If you are interested then I'll take a 3D photo to show the dot depth more clearly.
I'll draw some lines on the surface befor doing so, perhaps use a tripod too.
At present there are no marks on the surface of the glass, on the inital photo everything saw filthy.
I thought the mars were on the surface then.
I suspect the glass is a laminated construction and damp has got into the gap and caused the problem.
Kind regards, David.

[Paul_RK]

I don't know what's going on,  but I've a set here showing what looks like exactly the same effect, and wouldn't you know it's my KV-1800UB! I'm sure it looked normal enough when I was using the TV for a spell about 20 years ago, then it sat forgotten in a corner of our front room in County Durham, and I only noticed the speckled tube when placing the set in the bedroom here after our move at the start of last year. The front room in Langley Park had mild to moderate issues with damp, if that's relevant.

Paul

[Murphyv310]

So is the glass faceplate porous? If so the vacuum will be depleted.
I'd not be inclined to sit the set on its back. Tapping the CRT and debris falling on the gun could kill it in one foul sweep.
I'd really like to have seen these instances in the flesh. Remember I worked for Sony for 5 years and never saw anything like this before.

[Murphyv310]

Addendum.
Paul your photo shows the dots below the phosphors, so it's not the screen inside.

[djrm]

Greetings Paul,
That looks remarkably similar to my tube.
And yes, my set was stored in damp conditions too.
I wonder I could claim on the gaurantee!
Thanks for sharing, David.

[Murphyv310]

David.
Look carefully below the screen I can see these dots below it. I think it's a problem with the glass.

[Murphyv310]

https://www.badgerandblade.com/forum/thr...his.75557/

[Mark Hennessy]

So there we have two examples

Earlier I asked if these might be laminated CRTs, and the more I think about it, the more convinced I am about this. As I said, the fact it's coming in from the edges is the clue - moisture is reacting with the glue in some way.

Searching around, it does seem to be something that affects some 18" Sony CRTs. See post #6 of this thread: https://www.vintage-radio.net/forum/show...?p=1051145

It's often called "CRT Cataracts", and searching for that phrase returns lots of interesting results. Some people go to the effort of removing the outer layer and cleaning away the glues, but I'm not sure how safe that would be.

I haven't inspected my KV1820s for a while. They have been kept in warm and dry conditions, and the CRT in the 1800 is unique to that set as far as I know, so I'm hopeful. As mentioned earlier, one of them is an absolute minter - imagine how annoying it would be if it caught this disease

[Murphyv310]

http://www.videokarma.org/showthread.php?t=255714

Seems a problem that wasn't on the go in the 90's.