10-27-2015, 05:22 PM
Sounds like Silver Mica Disease in the IF's.... unfortunately it is getting more common as sets of this vintage age. Do a search and you'll find out more than you ever wanted to know about it 
https://www.youtube.com/watch?v=h1lsWaAkCGo

https://www.youtube.com/watch?v=h1lsWaAkCGo
John KK4ZLF
Lexington, KY
"illegitimis non carborundum"