[time-nuts] More information...DATUM 9390-52054 Grief again...

[Ed Palmer]

Hi Bert,

SV6 is the model number for an old Trimble 6 channel GPS board. Info is 
available online.  Maybe your receiver died.

Ed


On 4/6/2013 5:00 PM, Burt I. Weiner wrote:
> I notice that when it first turns on there is a message where I 
> normally expect to see "System Check ok."  The message reads:  
> N200/S116/DT202KP.  I don't know what this is saying.
>
> Burt
>
>
> (Note: additional information about the receiver module has been added.)
>
> Burt
>
> Gang,
>
> You will remember several months ago I had some stranges that I 
> thought were related to a defective Vectron oscillator in one of my 
> DATUM 9390-52054.  That turned out to be a the internal switching 
> power supply so I replaced it with an external Cisco unit.  I've done 
> this in three units, two are mine and one belongs to Stu, K6YAZ.
>
> Well, I now have a different grief in one of my units.  It had been 
> cooking along swell with no problem ever since I replaced the power 
> supply.  This morning I notice that one of my units had the lock and 
> tracking lights out.  The display said that the signal level was low 
> and there were no usable satellites.  The 10 MHz output is also about 
> 20 or more dB low.  I assumed the power supply is all right because 
> the display was working and it said it was 9-E9, not so good, but 
> working - sorta.  I swapped antennas and the good Datum was happy so I 
> know the antenna is ok.  when I got inside I checked the power supply 
> rails and they're within .05 Volts of where they should be.  There is 
> 5 Volts on the GPS module and there is 4.96 Volts on the antenna 
> Type-N connector (measured with the antenna line disconnected.)  Power 
> cycling the DATUM did not resolve the problem.
>
> Does anyone know if the symptoms above will occur if the 10 MHz 
> oscillator is defective?  I can understand it not tracking or not 
> locked, but could this cause the receiver to not see or indicate any 
> satellites?  Since I only have two of these units on line, I'm very 
> reluctant to start swapping modules because I would be without any 
> working reference, so I need to keep one up and running.  Both of my 
> units are on a UPS, and according to the clocks in the kitchen, the 
> bedroom, and the old VCR, we've not had a power interruption.
>
> I do not recognize the GPS receiver module, but it has the following 
> number on it:  TNL 22880-B.  I have the schematics for the overall 
> DATUM 9390-25054, but the GPS module in just a block. By the way, the 
> GPS block on the DATUM overall schematic is marked, "SV6 / (TANS)".  I 
> suspect this means something noteworthy.
>
> Any guidance would be appreciated.
>
> Thanks,
>
> Burt
>
> Burt I. Weiner Associates
> Broadcast Technical Services
> Glendale, California  U.S.A.
> biwa at att.net
> www.biwa.cc
> K6OQK