[time-nuts] Tale of Two GPStars...

[Steve - Home]

I have a GPStar that hadn’t been used in a few years. I’ve misplaced the wall wart power supply. Could someone pass along the output voltage and current numbers of the wall wart, please? I think I can figure out the DIN connector pin numbers but that would be helpful, too. My manual is pretty sparse in that area. If I recall it says “plug in the AC adapter”...

Thanks!

Steve K. 
WB0DBS



> On Jun 4, 2020, at 10:00 PM, paul swed <paulswedb at gmail.com> wrote:
> 
> Somebody else actually has a GPStar (Odetics) and working?
> My units stopped working about 4 months ago. They are circa 1994 as I
> recall. Had 2 neither would work. Have one now as I used the case and rack
> mounts for another project.
> These are much older then what you have as the GPS receiver is actually
> discreet components.
> Regards
> Paul
> WB8TSL
> 
>> On Thu, Jun 4, 2020 at 8:59 PM Bruce Lane <kyrrin at bluefeathertech.com>
>> wrote:
>> 
>>        After many moons, my trusty GPStar 365 (updated to a 565 through
>> firmware and a receiver change) finally bit the dust. Symptom: It kept
>> flipping between 'Coasting' and 'Recovering,' never quite reaching
>> 'Locked.' The DAC value either ended up maxed (65534) or min'd (00000).
>> 
>>        Contacted Tim Gavin at Zyfer-FEI for advice. Strongest possibility:
>> OCXO went south. Tried manually setting the DAC for mid-point (32768)
>> and manually tweaking the coarse tuning on said OCXO against a
>> known-good 10MHz source of equal precision (translation: Another GPSDO).
>> 
>>        Didn't work. Tried replacing the OCXO itself, and doing the
>> alignment
>> trick. Still no joy.
>> 
>>        Considering the lack of schematics: Emit large sigh, put unit
>> aside,
>> start searching Ebay for replacement.
>> 
>>        Found a late-model (black case) 565-310 for a reasonable price,
>> bought
>> it. Arrived a week later (yesterday at work). Opened it up, delighted to
>> find I got a better deal than I thought in that the thing's got a
>> rubidium module (FE-5650A to be exact).
>> 
>>        Did initial power-up/burn-in test with a local GPS antenna; Unit
>> went
>> to TFOM 4 and 'Locked' within a half-hour and stayed that way all day,
>> DAC number just slightly above mid-point.
>> 
>>        However -- Date way off due to outdated Motorola UT+ receiver
>> module.
>> Replaced said UT+ with the M12M drop-in module from Synergy GPS. Fired
>> up -- and got NO satellite tracking ID's!
>> 
>>        Mutter something vulgar. Do more poking around. Suddenly realize
>> the
>> firmware in the replacement 565 is at 1.06, while my original unit was
>> at 1.08. "I wonder if..."
>> 
>>        Swap 1.08 firmware chip into replacement 565. Power on. Goes
>> through
>> factory reset -- and comes up perfectly normal! Sat numbers appearing on
>> tracking report. Just checked it a moment ago (about 15 minutes after
>> initial re-power) and it's at TFOM 4 / Locked! And it stayed that way
>> through a 24-hour burn-in check.
>> 
>>        Conclusion: In the 565 series, you need version 1.08 firmware to
>> support Motorola's M12, or similar replacements.
>> 
>>        And I'm still amazed I lucked out with the rubidium module. ;-)
>> 
>>        Keep on tickin'...
>> 
>> --
>> ---
>> Bruce Lane, ARS KC7GR
>> http://www.bluefeathertech.com
>> kyrrin (at) bluefeathertech dot com
>> "Quando Omni Flunkus Moritati" (Red Green)
>> 
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