Hi,

Over the past few days I've been analysing a problem in my Eizo T766 19" CRT
(Sony Trinitron tube), with this group's help. Unfortunately, I can conclude
nothing else besides that the red and blue gun occasionally short to something
at low potential, most likely the heater. I tried tapping it loose, but with
no success. So, now I'd like to collect as much information as possible about
zapping the short out.

I've seen suggested that you can use a neon transformer (or other kind of tesla
coil) for this: connect both pins of the heater to eachother, and connect the
transformer between it and the affected cathode (one at a time). This seems
rather dangerous to me; such arcing usually leaves everything blackened. If
this is a good approach, what voltage neon transformer should I look for?

Another method is a capacitor charged up to several hundred volts; start with a
few uF, then increase as desired.

I would like to know, based on people's experience, how much chance I have of
blowing out the cathode or filament. Bear in mind that it's an intermittant
short, that does not show up on the DMM when the tube is unpowered (not even
on the 200 MOhm range), so in the most positive situation, we're talking about
loose debris which needs to get out of the way, and not a dead short.

One last question: is the heater filament an exposed (or covered?) fragile
filament like that in light bulb, or is more robust like heating wire of an
electric stove?

Any help is appreciated, and thanks in advance.

Wiebe Cazemier