[time-nuts] Z3801A holdover

Artek Manuals Manuals at ArtekManuals.com
Thu Feb 25 03:54:52 EST 2016


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
NR1DX


-- 
Dave
Manuals at ArtekManuals.com
www.ArtekManuals.com

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