[time-nuts] Re: RFTGm-II (KS-24019) XO Fault but GPS to Rb is OK

[Bob kb8tq]

Hi

I think you will find that the list of “visible” sats is coming from 
the stored almanac and your position (from the hold mode). 
You may have an antenna problem.

Bob

> On Oct 31, 2021, at 7:21 PM, k1jos at att.net wrote:
> 
> Here's a follow-up.. 
> 
> I took out the XO pcb's and powered it up stand-alone.  In the RFTGM
> software, it shows as Active, Warmup, No Fail code and it is outputting a
> clean 15MHz sine wave. In GPS - It's showing 8 visible Sats but Zero
> Tracking SATs and is "Acquiring SATS/Position Hold" .  The SAT IDs are
> listed but Signal Strength and Channel Status are all zero.  Its been
> powered up for about an hour so far.  Checking XO Voltages, all seems good
> Control=14.574V, Temp 36.49, Ant Feed 16mA.  The ADC = 0v as I think it
> would be in warm-up mode.   Now hopefully it will acquire and run for a
> while.   
> 
> Jerry
> 
> 
> 
> From: k1jos at att.net <k1jos at att.net> 
> Sent: Sunday, October 31, 2021 10:20 AM
> To: 'time-nuts at lists.febo.com' <time-nuts at lists.febo.com>
> Subject: RFTGm-II (KS-24019) XO Fault but GPS to Rb is OK
> 
> I have had a KS-24019 (L108-L109) pair running continuously for several
> years.  Now have a red LED Fault on the XO unit and the RB unit shows green
> LED On-Line status.   The NO-GPS LEDs are off on both the -XO and -RB units
> but if I disconnect the antenna - they do show Yellow NO_GPS status.   Got
> out my old XP laptop and ran the Lucent software.  The Rb (REF 0) is active
> and locked to GPS and working fine.  The XO says Unit Failed but the message
> code for the first 4 hex nibbles which should show alarm status are all zero
> bits so no failure code is evident.  The last 2 alarm nibbles are 53
> representing the # of hours since failure.  The GPS time is correct on the
> Rb but is fixed on the XO at 80-01-06 00:00:00.  The XO checksum shows PASS.
> Based on this the XO GPS is working, locked and sending correct GPS messages
> to Rb.   The XO CPU seems to be working as well so am I correct this seems
> to be a Osc failure?  Besides checking voltages (which I'm not sure what
> they should be) - any advice how to go about further testing sand repair? 
> 
> Thanks in advance
> 
> Jerry NY2KW
> 
> 
> 
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