Quote:
Originally Posted by ex seismic
If you are wanting to repair vintage valve radios be aware that the voltages on service sheets were measured with by modern standards a low ohms per volt meter, i.e. an Avo 7. Measuring them with a modern DMM will give erroneous readings which might lead you astray until you have the experience to allow for what will be too high readings. Therefore on my list for you is an Avo 7. This topic has been discussed before on here.
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Yes important to be aware of this, but I would not get too hung up about it. In my experience the majority of voltage readings will be very similar between a high impedance digital volt meter/multimeter and an analogue meter. Of course there will always be exceptions, such as a valve circuit with high impedance where the original voltage measurement (as shown on schematic) was done using a low Ohm/V analogue meter.
I view the voltage readings shown on schematics/service sheets as typical ball park readings, i.e. not absolute values that need to be obtained/matched, usually several/many volts either way is nothing to worry about (unless the stated voltage in question is a low value, like some cathode voltages). Most schematics will not show a tolerance for the listed voltages.
Of course always good to have more than one meter for comparison measurement purposes and hard to beat a good Avometer.
For me personally the most importance pieces of test gear is a multimeter and a scope.
David