[time-nuts] Re: HP Z3801A - Dead GPS Receiver - Oncore VP

[CFO]

>>> My Z3810 had begun to show Alarm on the GPS receiver.
>>> On Coldstart it seems like it lives for 10min or so , and the enters 
>>> alarm state.
>>> I'm quite sure it's the GPS receiver that has gone to "heaven" , 
>>> never got that "Coldstart" every 6 months incorporated in my routines
>>>
Well (Oopz - It is a Z3801A i have)

I dug out the Z3801 from storage (10 months), gave it a new 48V PSU and 
started it up.
To my surprise it locked to 3 sats, after a few hours. And is now 
happily humming away.
I did "quick" test the old 48V PSU, loaded with 600mA. And it keept the 
48V fine, doubt it was the cause.

The "Lady" (Heather) shows that, The "Old Lady" (Z3801A) has 122700 
active hours (14yr)
Maybe it was the GPS oscillator that needed that restart, as per the 
service note.

https://synergy-gps.com/wp-content/uploads/2019/06/VP_SERVICE_NOTE.pdf
****** SNIP ******
Turn off all power to the GPS unit. The unit must be completely powered 
down for
at least two minutes. After two minutes, turn the power on.

This procedure should be performed every three to six months. This will 
allow the unit
to perform a self-diagnostic routine and recalibrate an internal 
component for optimal
performance.
****** SNIP *******

The SN explicit says "Turn off all power for minimum 2 min", would that 
have influence on the OCXO stability ?
Wonder why a : *TSTÂ Â  - Would not do it (The reboot & cal)Â  .. Anyone 
have an idea ?


Thank you goes to the nice person that off-list offered to have a look 
in the "drawer" for a VP.
Let's see if it's still needed.


CFO
Denmark