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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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Thread Tools |
9th Apr 2024, 7:32 pm | #1 |
Pentode
Join Date: Dec 2019
Location: Egersund, Norway
Posts: 208
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Defective Avo vcm 163 gm meter substitution
Hello again, I have a avo vcm 163 that needs a replacement gm meter. My plan is to use an op-amp amplifier pcb, using the original input signal from the vcm to the meter and use a 100uA meter. I think the op-amp input circuit must be similar to the gm meter load resistance (I beleave about 1,5Kohm but is not sure as the meter coil is broken an can not be neasured. Are there any precaution regarding the output from the op-amp driving a replacement meter? I have a circuit (maybe made by Martin, Decatron), and I have earlier made a replacement for the ma/v meter on a avo mk3. So far this has worket out fine. Hints and advices are most welcome!
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