Most likely, internal flashover in the CRT. In seldom cases, the arcing might be caused by dust and dirt in the spark gaps, try cleaning them with compressed air.
jloy1
Posted: Wed Jul 23, 2008 1:28 am Post subject: crt plugs....
i have to crt plugs that have small pinholes thru them that allow voltage escape and arcing....first can these be replaced and secondly what would cause this?...bad high voltage splitter?