NotTaR of Television Sets : Rescuing a shorted CRT                  
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Rescuing a shorted CRT

If the short is filament-cathode (H-K), you don't want to use the following approach since you may blow out the filament in the process. If this is the case, you may be able to float the filament and live with the short (see the section on: "Red, green, or blue full on - fog over picture".

Shorts in the CRT that are between directly accessible electrodes can be dealt with in a more direct way than for H-K shorts. At this point you have nothing to loose. A shorted CRT is not real useful.

If the short is between two directly accessible electrodes like cathode-grid, then as a last resort, you might try zapping it with a charged capacitor. Start with a relatively small capacitor - say a few uF at a couple hundred volts. Check to see if the short is blown after each zap - few may be needed. Increase the capacitance if you fell lucky but have had little success with the small capacitor.

If the fault is intermittent, you will, of course, need to catch the CRT with the socket disconnected and the short still present. Try some gentle tapping if necessary. If you do this with the charged capacitor across the suspect electrode, you WILL know when the short occurs!

Also see the section: High voltage to focus short.