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Old 12th Jul 2018, 10:23 pm   #4
Bazz4CQJ
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Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,920
Default Re: VCM163 Calibration Question

That service manual never went past a technical editor! I hadn't spotted that mistake but the whole thing is jumbled up.

I've been looking at my old notes to try and see how I've set the oscillator up previously but cannot find any specific mention. However, I don't have a DMM which would measure 15mV AC so I guess I must have used the scope to do it. I did make a note that I reckoned the frequency was 15.8kHz (not the 14.7 usually referred to) so that also implies I had the scope on it.

My 163 has a meter on the gm side which is faulty (shorted turns on the coil) so I've had to fit an op-amp in there to achieve a correct reading. It always seems to me that owning an AVO VCM is a hobby in its own right.

B
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