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Valve/tube, A/R fault

Well that is what Avo calls it, I've never come across one before. ECC83 with curious cyclic swirling breaking-surf whitish-noise and clicks. Putting on Avo 160 tester showed short in A/R setting, I've never had before, A/R here stands for cold checking Anodes To Remaining electrodes. DVM cold resistance checking pin to pin showed about 9K between an anode and its grid. I will replace it but is there any point in blasting with some high voltage to vaporize whatever is bridging, for a known unreliable/short-term spare. I'm aware that a valve with leaky C to H, then running the valve with 10 or 12V on the heaters insted of 6.3V so they glow like bulbs for a few seconds, will knock back the bridging deposit for a few months or even years.

Reply to
N_Cook
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Used to do that with a TV CRT rejuvenator. It had a specific function to remove shorts. Sometimes worked, sometimes didn't.

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Reply to
Meat Plow

3
r
C

Same here. I still have it and use it about once every couple of years, now on monitors rather than tv crt's.

Reply to
hrhofmann

Same here. I still have it and use it about once every couple of years, now on monitors rather than tv crt's.

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Any idea what is causing this A/G resistance? Nothing to loose, I will blast it with some volts. But preliminaries I've seriously banged the envelope and heated it with hot air and the resistance has hardly moved from 8.7K ohm. C/H leakage I've never seen below about 100K IIRC and was highly variable on knocking the envelope.

Reply to
N_Cook

Ack! When did Caputo start doing that?

Reply to
JW
60V supply over A-G, dropped the resistance to 4.6K . Tried on a 500V Megger, not expecting to do much as only battery powered. Small white flash from inside and ohmage shot up to over 200M. Testing on valve tester and checks out fine
Reply to
N_Cook

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