[time-nuts] HP5065A Rubidium 2nd Harmonic Readings

[John Miles]

There are a couple of 20 uF axial tantalum electrolytics across the B-C
junctions of the pass transistors for both the lamp and cell heaters.  They
were open in my 5065A when I got it, and there was some overheating damage
on the lamp driver PCB.  Correlation != causation, but since I'm not sure
what those capacitors were actually supposed to do in the first place, I
think they're worth checking.

-- john, KE5FX

> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
> Behalf Of paul swed
> Sent: Friday, October 29, 2010 6:02 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] HP5065A Rubidium 2nd Harmonic Readings
>
>
> John,
> Interested. How might you connect the oven controller to what he
> is seeing?
> Bad caps causing it to oscillate, 60 hz modulation, ......
> I have a 5065 so am always interested in tid bits that I read.
> Thanks
>
> On Fri, Oct 29, 2010 at 12:34 AM, John Miles <jmiles at pop.net> wrote:
>
> > How's the photo current?  Does it vary as well?  If not, I
> don't think I'd
> > be too worried about the physics package.
> >
> > I would, however, check the electrolytics on the oven controller board.
> >  You
> > don't want an oven controller failure.
> >
> > -- john, KE5FX
> >
> > > -----Original Message-----
> > > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
> > > Behalf Of Brian Kirby
> > > Sent: Thursday, October 28, 2010 9:15 PM
> > > To: precise time
> > > Subject: [time-nuts] HP5065A Rubidium 2nd Harmonic Readings
> > >
> > >
> > > I recently had a long term power failure and ran out of UPS time.  The
> > > power was out over a day and when I returned home, it had
> been restored.
> > >
> > > The rubidium recovered, I hit the logic reset button and start and got
> > > the green light.
> > >
> > > I made some meter readings, and noticed something I have not seen
> > > before.  The 2nd Harmonic reading is showing 30 and its bouncing up to
> > > 31 about every 2 to 3 seconds.
> > >
> > > Otherwise, the unit seems to be performing nominal.
> > >
> > > Anybody ever seen this ?  Hope its not trying to tell me
> failure of the
> > > cell is on the way...
> > >
> > >
> > > Brian - KD4FM
> > >
> >
> >
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