Wiebe Cazemier wrote in
b.home.nl:

Hi,

I've been having troubles with an Eizo T766 19" CRT; the blue and red
gun occasionally turn fully on, most notably when tapping the neck
board, with visible verticle retrace for that color. At first I
thought I narrowed the problem down as being inside the CRT, because I
desoldered the offending guns' pins from the neck board, and the
problem remained. However, it has come to my attention that the
problem could also very well be in the CRT socket, the spark gaps to
be precise. The "Notes on the Troubleshooting and Repair of Television
Sets" article on www.repairfaq.org says this about it:

Except for the high voltage to other places, the short may actually
be
located in the CRT *socket* or even on the CRT neck board, probably in
the spark gap(s) for the problem pins. Remove the socket and test
between the suspect pins on the CRT itself. If the CRT itself is fine,
the spark gaps should be inspected and cleaned/repaired and/or
components replaced.

I don't know a lot about CRT's, and their sockets, so I've got a
question. What are the spark gaps? Are those the holes next to the pin
connectors? The socket for my tube is shown in [1]. And how do I
repair them (if they are what I think they are, they are difficult to
reach).

The short does not measure with the continuity tester on my DMM, and
not even with the 200 MOhm resistance tester (neither with the socket
connected to the CRT, or hanging loose, so it's difficult to test if
the socket is actually the cause. But if it were, would I measure a
short between the pin connector and ground?

[1] http://www.halfgaar.net/posts/2008-05/eizo-crt-socket


I believe the spark gaps look like disc capacitors with a slit in the
top edge.
I had a TV with bad solder joints on the CRT socket PCB,caused similar
problems.

the CRT socket could be loose for some pins.(the individual pin sockets
being spread open too much,not gripping the CRT pin tightly)

--
Jim Yanik
jyanik
at
kua.net