[time-nuts] 5061's on ebay

J. L. Trantham jltran at att.net
Thu Feb 23 13:30:33 UTC 2012


The Ion Pump I is measured as a voltage across a resistor in the +3500 VDC
supply in the return path from ground.  This supply is capable of providing
only a small amount of current and will collapse to zero volts if
overloaded.  Likewise, it can fail for a number of reasons, due primarily to
it's age.  It can be repaired by opening it using a 'torch' to melt the
solder seal at the bottom.  Keep the heat low, along the bottom.  The 'lip'
is only about 1/8th of an inch or so.

I have had issues as you are referring to for a number of reasons:

1.  A CS tube with a short from the +3500 to ground.  Fixed by using the
+3500 VDC supply to charge a 4 uF 4 KV capacitor then 'discharging' the
capacitor through the CS tube's +3500 connection to ground (be careful if
you wind up trying this).
2.  Failed +3500 VDC supplies for a number of reasons including an internal
'shunt' (not quite a 'short' but becomes as much at high voltage) of the HV
lead to ground, shorted internal electrolytic on the +18 VDC supply
Line, and open HV diodes.

The unit I recently purchased has an FTS tube, known to, typically, have a
very good 'vacuum' and low Ion Pump I.  It is functioning because, when the
CS Oven turns on, the Beam I goes up, slowly, as it should.  In addition, at
initial turn on, the Ion Pump I went off scale, as it typically does when
first turned on after a long period of inactivity, then fairly promptly (30
to 60 minutes) 'pumped down'.

These units are fun to play with but are terribly addicting.  Be careful.
You might wind up with several.

Joe

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Azelio Boriani
Sent: Thursday, February 23, 2012 4:57 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] 5061's on ebay


The ion pump current at 0 is not good. At work they bought an FTS4065B
without telling me before: instead of a very old FTS4065, there is an
already working PRS50. Anyway if the ion currect is 0 check the HV generator
first. Check this http://www.ke5fx.com/cs.htm on how to try to reactivate
the ion pump using an external HV power supply.

On Thu, Feb 23, 2012 at 5:28 AM, J. L. Trantham <jltran at att.net> wrote:

> I think so. But time will tell.
>
> I also have some units with bad tubes and this looks promising.
>
> Joe
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] 
> On Behalf Of Tom Knox
> Sent: Wednesday, February 22, 2012 10:20 PM
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] 5061's on ebay
>
>
> It sounds like you hit a home run Joe. If the tube is good the rest 
> should be easy. There are quite a few clean clocks with only a bad 
> tube.
>
> Thomas Knox
>
>
>
> > From: jltran at att.net
> > To: time-nuts at febo.com
> > Date: Wed, 22 Feb 2012 21:15:59 -0600
> > Subject: Re: [time-nuts] 5061's on ebay
> >
> > I purchased a 5061A with all parts installed and with the FTS tube.  
> > The 5061B with the FTS tube was listed later and sold.
> >
> > The unit seems to operate with good Beam I, good 2nd Harmonic, and 
> > almost zero Ion Pump I but it will not 'lock'.  I have not had a 
> > chance to look into it yet but I suspect an issue with the A7 or the 
> > A8 assemblies.
> >
> > If anyone is interested, I'll keep you informed.
> >
> > Joe
> >
> > -----Original Message-----
> > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] 
> > On Behalf Of Dave Welch
> > Sent: Wednesday, February 22, 2012 9:09 PM
> > To: Discussion of precise time and frequency measurement
> > Subject: Re: [time-nuts] 5061's on ebay
> >
> > Hi all.
> > I PURCHASED THE FTS UNITS AND ONE OF THE HP5061a. Havent had time to 
> > look at them but one of the fts powers up but i dont have any docs 
> > to figure
> out
> > what os wrong..it says ion current is 0.
> > Should this be that low??
> > On Feb 22, 2012 3:21 PM, "Tom Knox" <actast at hotmail.com> wrote:
> >
> > >
> > > The same seller also had some 5061B's and FTS 4065A's as well, all 
> > > were untested or in various states of disrepair. I was tempted on 
> > > a few the
> had
> > > missing parts not related to the Tube. Did anyone purchase any of
> these?
> > >
> > >
> > > Thomas Knox
> > >
> > >
> > >
> > > > Date: Wed, 22 Feb 2012 15:17:42 -0500
> > > > From: bownes at gmail.com
> > > > To: time-nuts at febo.com
> > > > Subject: [time-nuts] 5061's on ebay
> > > >
> > > > There are 3 5061's listed on ebay at the moment. Anyone know 
> > > > anything
> > > about
> > > > them?
> > > > _______________________________________________
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