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Ralph Mowery

In article , says...

DMMs and VOMs give different readings in certain circumstances (see
Ralph's post). In GB (at least) for a long time the service manuals for
decent gear would provide expected voltage readings for 20k OpV analogue
meters, the AV0 model 8 specifically IIRC, which saved the technician the
extra bother of scratching his head when checking hi-z parts of a circuit.

Yes, I have seen some schematics specify the voltage was measured with a
certain ohms/volt meter. It does take some guess work or head
scratching out of the servicing. Makes a big difference when measuring
the screen votltage that is fed with a high value resistor and you use a
vtvm or a 20 k ohms/volt or a 5 k ohms /volt meter.

I don't think I have done any trouble shooting on a tube circuit in 20
or 30 years. Last thing I recall even looking at with tubes was my
Heathkit sb101 that was many years ago. Only other thing I have with
tubes are a couple of RF amplifiers and they use voltages that I don't
work on with any power on them.