CRT sockets did go especially on flat chassis solid state sets. Usually
caused by excessive focus voltage but can happen with normal F.
The problem is with the spark gap part of the socket. Another test is
to pull the ground straps off the DGS shield & measure them with a
HV probe. Should be zero volts. As John said noise, smell, & physical
damage works as well. If we had a junker repair we would cut up the socket
& eliminate the SG to get it out the door. It was better to do that, make a bucks & give the customer a little more time. Otherwise its the dumpster
& zero cash flow.
73 Zeno
LFOD !