HEATH Digest - 31 Mar 2009 to 1 Apr 2009 (#2009-66)

[Ron]

Early VTVMs such as the V7A had separate inputs for
DC and AC/Ohms. Later models used a switchable
probe with a single input. It is very easy to modify a
V7A to use a switchable probe (without affecting its
ability to use the two separate probes).

-- Ron



Bob Bruner WB4TAJ wrote:
> I built a Heathkit V-7A in the 50s.  It came with an entirely conventional Switchcraft 1/4-inch plug for the DC Volts probe.  In this model they had you install a 1 megohm resitor in a regular 
> black test probe, using about 30 inches of cheap spiral wrap shielded audio cable for the test lead.
> The ohms probe was a similar red probe that plugged into a banana jack and no switch was involved.
>   Over the years, I worked on a
> lot of transmitters with that VTVM, and I never had any problems with the conventional phone plug or
>
>
> or the cheap audio wire arcing.
>
> Bob Bruner 
> W9TAJ
>   
>
>   
>>> Date:    Tue, 31 Mar 2009 20:30:59 -0400
>>>       
> From:    Keith Harvey <keith.harvey at PERSONA.CA>
> Subject: VTVM 1/4" plugs..
>
> If you can find some military surplus headsets (oldies) they usually have a 
> PJ-055B plug. These have a much wider insulating band between the tip and the
> sleeve. 
>
> Keith Harvey VA3KRV
>   

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