[time-nuts] Z3801A recovering

Joseph Gray jgray at zianet.com
Sat Mar 19 01:56:49 EDT 2016


The saga continues. Last night, I hooked up the second Z3801A that I
got recently. At first, it was having a hard time finding satellites
and then locking. I did a PRESET and started a new survey late last
night. All day and this evening, it has been operating flawlessly.
Tonight, I did a quick power cycle to get the date set correctly.

https://dl.dropboxusercontent.com/u/19599147/Z3801A%20%232.png

>From the graph, you can see where I restarted it at the left. It then
runs fine for several hours. But look at the latest. And of course, it
keeps going into holdover. During all of this, it has been tracking
from 2-6 satellites, mostly about 4-5. So, unit #2 definitely has a
problem.

It's late, so I'm going to leave it alone until tomorrow, when I'll
open it up and probe around a bit. I'll pay particular attention to
the tantalum caps, which someone mentioned. As old as these things
are, it wouldn't surprise me if some were bad.

Joe Gray
W5JG

On Fri, Mar 18, 2016 at 8:21 AM, John Green <wpxs472 at gmail.com> wrote:
> Joe, I'd be interested in knowing what you find out. My Z3801 is acting a
> lot like yours. It is currently locked, but.
>
> On Thu, Mar 17, 2016 at 8:15 AM, Joseph Gray <jgray at zianet.com> wrote:
>
>> Dave,
>>
>> I power cycled it about 20 days ago, which did no good. That is the
>> 496 hours holdover time. This time, I did just the survey once
>> command. I'll try your suggestion before attacking the hardware. I'm
>> currently using Z38xx.exe.
>>
>> Joe Gray
>> W5JG
>>
>>
>> On Thu, Mar 17, 2016 at 4:30 AM, Artek Manuals <Manuals at artekmanuals.com>
>> wrote:
>> > Joe
>> >
>> > I am confused by the fact that it shows the unit has been in HOLDOVER for
>> > 496 hours if you did a fresh survey
>> >
>> > Did you do a SYSTEM:PRESET: and GPS:POS:SURVEY:ONCE commands to initiate
>> the
>> > new survey or just the survey command or ???? What software are you
>> running?
>> >
>> > I would power the unit down and let it sit for 24 hours and then do the
>> two
>> > commands above.
>> >
>> > What software are you running?
>> >
>> > Dave
>> > NR1DX
>> >
>> >
>> >
>> >
>> >
>> > On 3/16/2016 7:38 PM, Joseph Gray wrote:
>> >>
>> >> As I mentioned a while back, my trusty Z3801A, which has worked well
>> >> for several years, went into holdover some time ago and stayed there.
>> >> Until recently, I haven't had time to look into this. About 20 days
>> >> ago, I did power cycle it to see if that made a difference. It did
>> >> not.
>> >>
>> >> In the middle of the night, last night (couldn't sleep), I decided to
>> >> see what initiating a new survey would do. Since the unit doesn't lock
>> >> to as many satellites as my Lucent with the newer Oncore, it took
>> >> quite a while for the survey to finish.
>> >>
>> >> I just got home from work and this is what I am seeing:
>> >>
>> >> https://dl.dropboxusercontent.com/u/19599147/Z3801A.png
>> >>
>> >> The good news is that the unit no longer telling me the PPS is
>> >> invalid. It looks like it will be another long while before it comes
>> >> out of Recovery (assuming the PPS stays locked).
>> >>
>> >> I'm not the best at interpreting these graphs. At this point, should I
>> >> be concerned abouth the spikey nature of the EFC graph, or will things
>> >> calm down eventually? I assume that the PPS graph won't show until
>> >> Recovery is done?
>> >>
>> >> If this unit loses PPS lock again, or otherwise acts up, then I would
>> >> assume it is a hardware problem, and I'll have to put it on the bench.
>> >>
>> >> Joe Gray
>> >> W5JG
>> >> _______________________________________________
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>> >
>> >
>> > --
>> > Dave
>> > Manuals at ArtekManuals.com
>> > www.ArtekManuals.com
>> >
>> > ---
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>> >
>> >
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