[time-nuts] Z3801A holdover

Joseph Gray jgray at zianet.com
Thu Feb 25 09:09:28 EST 2016


Thanks for the tips. I also got a message off list telling me about
the EFC issue and that I missed this discussion recently on the list.

Last night, I power cycled the Z3801A. It has been running all night.
Attached is the graph you requested. If I read this correctly, yes, it
looks like the unit has maxed out the EFC voltage one way.

Joe Gray

On Thu, Feb 25, 2016 at 1:54 AM, Artek Manuals <Manuals at artekmanuals.com> wrote:
> On 2/24/2016 11:37 PM, Joseph Gray wrote:
>> I just took a look at my Z3801A that has been in holdover for some
>> time. I have been too busy to do anything about it until now.
>> Before looking at the receiver stats just now, my first guess was that
>> the Oncore GPS board went bad. However, I see that it is currently
>> tracking 4 sats. I also see that the 1pps is invalid. Does this still
>> point to a failed Oncore board?
>> Attached is a screenshot showing the receiver stats.
>> I will open this thing up over the weekend to check voltages and such.
>> Until then, any tips on where to look are appreciated.
>> Joe Gray
>> W5JG
> Joe
> I'm no expert since I've only just begun playing with my Z3801A for the last
> 6 weeks after having it in mothballs for 15 years but having just gone
> through a Oncore failure on the surface it seems unlikely I would wish for
> slightly better signal strengths but I dont know what you experienced in the
> past.
> I am led to believe that EFC errors are typically associated with the
> Oscillator unit itself rather than the Oncore receiver,My first guess after
> that is the 10811 oscillator has "aged" out of a correctable range. In Z38xx
> program open the the graph window and send us a screen shot of that window,
> this should give us and idea of what the actual EFC value and behavior was
> just before things died.
> My next instinct ( but wait for a few other more experienced comments come
> out) is to turn the unit off and let it cool down for a day then do a cold
> start :SYSTEM:PRESET followed by a GPS:POS;SURV:ONCE command and see if it
> re-initializes. Takes about 2 hours typically since you have known good
> position  data.
> There is a description of the power supply and oven control circuitry for
> the oven on KO4BB.com .search for Z3801A in the MANUALS section You are
> basically looking to see if +/- 15VDC and +5VVDC lines are correct
> Dave
> --
> Dave
> Manuals at ArtekManuals.com
> www.ArtekManuals.com
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