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