Question: re ....Work around to 1 meg in Heath IM-28 probe?

[Tom Bridgers]

Hi....
    Just found out that instead of having to use the probe with the built-in
switch that permits the switching in a 1 meg resistor for use on DC, that a
probe without a switch can be used (in other words, using a direct through
probe).  What you do is modify the connections to the function switch,
internal to the IM-28, so that the 1 meg resistor is switched in the circuit
whenever the VTVM is switched to either DC+ or DC-.
    My question is this:  I thought having a 1 meg resistor in the probe was
necessary for the probe to be "isolated" from the VTVM...  What is the
theory behind this?  And at day's end, will the VTVM function properly (give
just as accurate results) with the 1 meg resistor now internal to the VTVM
and approximately 36 inches from the probe?
thanks for any info you could shed on this..
-tom   KE4RHH

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