[R-390] hp 410B VTVM ( for working on my R-390A)

[David C. Hallam]

The contact spring and tip that go on the anode of the two tubes are
different also.  I have never seen a probe with a 2-01C so I don't know what
the difference is but they are listed as separate part numbers in the
manual.

David
KC2JD/4

> -----Original Message-----
> From: r-390-bounces at mailman.qth.net
> [mailto:r-390-bounces at mailman.qth.net]On Behalf Of wabate
> Sent: Monday, March 24, 2008 9:09 AM
> To: R-390
> Subject: Re: [R-390] hp 410B VTVM ( for working on my R-390A)
>
>
> Thanks, Barry and David.  What I should have said is that the original
> tube was the 2-O1C but HP later modified the probe in the 410-B to
> accept the EA53.  THe filament voltage is different as well but only an
> adjustment is required to compensate.
>
> 73,
>
> Bill, K3PGB
>
> Barry wrote:
> >>Sam,
> >>
> >>I would not want to change to a SS diode, as tempting as that might be.
> >> A 1N66, etc. would be OK but you would loose a lot.  Diodes are
> >>limited to about 20 vac and 250 MHZ but the 2-O1C can handle over 300
> >>volts, depending on frequency.  The upper frequency limit is over 700
> >>MHZ.  Hard to duplicate that with a SS diode, unless a 20 volt limit is
> >>OK for your app. The 410-B should use the 2-O1c not the EA-53,
> unless it
> >>has been modified. BTW, I have 2-O1C, NIB.  Trade?
> >>
> >>73,
> >>
> >>Bill, K3PGB
> >
> >
> > I don't think that's correct.  HP built the 410B for both
> diodes in different probe configurations.
> >
> > Barry - N4BUQ
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