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Old 1st Dec 2015, 11:49 pm   #87
Phil G4SPZ
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Join Date: Apr 2005
Location: Bewdley, Worcestershire, UK.
Posts: 4,342
Default Re: Test equipment for valve radio repair

Originally Posted by G6Tanuki View Post
Someone I know spent ages failing to identify an open-circuit IF transformer primary because they 'insisted' they were seeing +200-odd volts of HT on the anode-pin of the IF stage (with the valve removed)... A 'classic' 20KOhm/volt meter like an AVO8 or a Taylor would not have showed any significant voltage.
I remember a similar situation in an industrial electrical circuit where there was enough leakage through a blown fuse to read 415 volts on an Avo 8, yet the traditional test lamp stayed dark.

The Avo 8 was designed for the emerging solid-state era to enable low voltages in transistor circuits to be measured with minimal loading, and it's probably not the best meter to use with valve equipment, for which the Avo 7 still takes some beating!

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