[Test-Equipment] HP 410C

[Ron Youvan]

> Hi. I have a pretty nice HP 410C. I bought it several years ago, and it 
> works ok on DC and Ohms. It did not come with the 11036A AC / HF probe. 
> I have since acquired one. Although I 'swear' I have several EA53 tubes 
> here (somewhere) I also have several NOS 2-01C tubes, in my hot little 
> hands. I was reading the instruction sheet that came with the 2-01C 
> tube and they describe 'adjusting R50' (this sheet only talks about the 
> 410B), for 5.0 V rms. They DO describe adjusting R50 for 6.3 V when 
> using the EA53.
> OK, I have a Manual for my 410C, and nowhere do I see how to adjust the 
> voltage.

   If you use a 5 Volt tube in a 6.3 Volt application you can add one or more
resistors in the meter box feeding the probe cable.  Or a rectifier + filter
and a 5 Volt at up to 1.5 Amp. regulator in the meter case.

> I DO understand that the 410C supplies 6.3 V AC to the probe filaments 
> when in modes OTHER than AC. When AC is selected, the filament voltage 
> is changed from AC to DC. It 'looks' like the probe filament voltage is 
> 6.3 V. Period. Is the 410C limited to using JUST the EA53, where the 
> 410B could use both???
> Sooooo, it would 'appear' that the 2-01C cannot be used with the 410C. 
> Is this correct? Man, I DO NOT want to buy a EA53!! Can I just 'drop 
> the filament voltage to 5 V? How long will a
> 2-01C last at 6.3 V??????
> 
> HELP!!!
> 
> I know that 'somewhere here', I have a ton of info on these great 
> voltmeters. However, a divorce and 3 moves can scatter yoiur 'stuff'.. 
> ha ha

   Not funny.

-- 
    Ron  KA4INM - around here the government employees have become quite skilled at taking
                  every opportunity to TAX and it shows.  (while giving very poor service)