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Old 5th Jun 2020, 2:44 pm   #30
ms660
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Join Date: Apr 2011
Location: Cornwall, UK.
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Default Re: AVO VCM MK3. Meter needle not moving when switched on.

Quote:
Originally Posted by HBWOODY View Post
I have been looking at the attached jpg of the Set circuit for the CT160 to help me understand the SET circuit of my Mk3. Is there a similar circuit for the MK3 available?
It's basically a halve wave circuit for the grid voltage when the valve under test is conducting and a full wave circuit for the meter when in the set position.

Don't forget that for the meter needle to reach the set position on the scale the meter switch has to be set to a current range other than the 120mA or 180mA range, if not then the supply to the meter will in effect be half wave which will result in a much lower indication than otherwise.

If I get time I'll draw a simplified schematic and post it up on here.

Lawrence.
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