Another comment, there was a common mod for the Heathkit VTVMs propagated by those who didn't know any better that moved the probe resistor to the inside of the unit on the function switch. I guess they thought Heath didn't have engineers or something...
The mod is reversible of course but it decreases the value of the unit because you have to reverse a mod.
73
-Jim
NU0C
On Fri, 19 Mar 2021 18:12:58 +0000
"Dick" <w1ksz@...> wrote:
A comment on the need (or not) for a VTVM.
If you are measuring the Grid of an Oscillator, check if the Digital Meter
has a Resistor in the probe.
I had this issue checking a Drake R-4B ... the Keithley VTVM killed the
oscillation, while the RCA Voltohmyst did not. The 10 Meg Resistor in
the probe made all the difference.
Jim Shorney