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

[Bob kb8tq]

Hi

You can be pretty sure that in their original installations
as a reference for a cell tower, shutting the whole thing 
down every couple months was not part of the spec. 

Bob

> On Oct 12, 2021, at 12:47 AM, CFO <tnut1 at sv16.org> wrote:
> 
> 
>>>> 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 : *TST   - Would not do it (The reboot & cal)  .. 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
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