[time-nuts] 5062C

[Predrag Dukic]

John,

Is that, now unusable tube  a surplus for You?  I'd have some use for it...

(sectioned, as a display for an University lab)..


Predrag Dukic
University of Split
Croatia







At 08:29 23.3.2009, you wrote:
> > There's an HP 5062C closing on eBay soon!
> >
> > Corby
> >
>
>Thanks for the heads-up, Corby, even if it incited a bidding war. :)  I
>bought it and got it working without much trouble.  The problem turned out
>to be a resistor that had drifted high and crowbarred the oven-temp shutdown
>circuit.
>
>Its cesium tube is elderly but still has some life in it.  Beam current is
>about 0.47V at the test point (or 10 on the front-panel meter) with the
>mass-spec voltage at the first peak of 12.0V, and about 0.68V (~12 on the
>meter) with the mass-spec voltage at its highest peak, at 17.5V.
>
>Question: the 5062C manual has some contradictory instructions for setting
>the mass-spectrometer bias.  Page 4-45 says the adjustment is "correct" when
>the beam current is at its lowest-voltage peak.  Page 4-56 says "More than
>one peak may be indicated... Set MASS SPEC control for highest peak."  Which
>is optimal?  In my case I see a lot more beam current at the 17.5V peak than
>at the 12.0V peak, so I'd rather leave it at 17.5.
>
>The bad news is that when I tried installing my spare 5062C Cs tube, which
>I'd previously bench-tested successfully, the hot-wire ionizer filament
>opened up at some point during the periodic supply-cycling process that
>takes place until the ion pump current falls to its normal operating value.
>That sucked, because now I'll never know how the bench test results compare
>to actual performance in the clock.
>
>I don't see anything I might've done wrong when I installed the other tube.
>There was just too much O2 in the envelope, I guess...
>
>-- john, KE5FX
>
>
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