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

[wabate]

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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