[time-nuts] HP OCXO in 5016A.....

Brian, WA1ZMS wa1zms at att.net
Tue Sep 11 22:36:38 UTC 2012


Joe-

I have the manual. I trimmed the OCXO against my Z3801A before closing the
loop. That's when the "slew" took place, after loop was closed.
Green light bulb is OK. :-)


Sounds like A8 is the issue. Although the 2nd harmonic value (A7) is not as
stable as my other 5061A is when loop is closed. Could be a clue.
Time to get it up "on- blocks" on the bench and see just what is going on.

Thanks to all! :-)


-Brian, WA1ZMS

-----Original Message-----
From: J. L. Trantham [mailto:jltran at att.net] 
Sent: Tuesday, September 11, 2012 6:07 PM
To: wa1zms at att.net; 'Discussion of precise time and frequency measurement'
Subject: RE: [time-nuts] HP OCXO in 5016A.....

Brian,

Do you have a GPSDO?  If so, with the Loop Open, you can adjust the OCXO to
exactly 5 MHz and watch that it is stable.  Once done, then select Oper and
wait until Beam I and 2nd Harmonic come up.  Then hit the Reset Button and
watch what happens to the 5 MHz, compared to your GPSDO.  If it slews off
frequency, then it shows a signal is getting to the OCXO and, likely, A9 is
OK.  If it stays put, A9 could be a problem.  If the 2nd Harmonic falls when
you turn off MOD, then A7 is likely OK and the problem is more likely in A8.

Also, when you unplug J1 from A7, Beam I and 2nd Harmonic should fall.  If
so, A7, again, is likely OK.

I have also had failures in A14.  Make sure the bulb is not burned out.

Do you have a manual?

Good luck.

Joe

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Brian, WA1ZMS
Sent: Tuesday, September 11, 2012 4:50 PM
To: Time-Nuts
Subject: [time-nuts] HP OCXO in 5016A.....

Does anyone has any info on the HP-00105-6013 Series 1248

OCXO that is/was used in the HP-5061A?

 

I have a newly acquired 5061A that has "issues".

It has an FTS tube in it, and while there is beam current

and plenty of 2nd Harmonic, the alarm light does goes out,

but this unit is not yet a member of the "Green Light Club"

in that the continuous operation light fails to light.

 

The control loop appears to try and slew the OCXO

way off frequency.  My best guess is a defective A7

AC amp module.

 

Time to trouble shoot! :- )

 

Comments welcome.

 

-Brian, WA1ZMS/4

 

 

 

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