[time-nuts] Re: Symmetricom XLi question

[Bob kb8tq]

Hi

The Symmetricom X72 GPS is indeed a compact Telecom RB. Like pretty much all of them,
there is no real source for schematics or troubleshooting. The normal approach for a dead 
one is to send it back to the factory. Even working out minor things isn’t very easy.

Bob

> On Sep 21, 2022, at 1:46 PM, paul swed via time-nuts <time-nuts at lists.febo.com> wrote:
> 
> Well the easy thing is to check the supplies. But that will end up being 1
> supply typically something like 21-24 volts. I am guessing the RB is a
> typical telco Rb. These are small units. There is a good chance the lamps
> not lit. Depending on the actual unit like a FRS they actually have signals
> to show the lamps lit or not. From that point you can try to figure out
> what the next step is.
> Regards
> Paul
> WB8TSL
> 
> 
> On Wed, Sep 21, 2022 at 2:35 PM Mark G Thomas via time-nuts <
> time-nuts at lists.febo.com> wrote:
> 
>> Hi,
>> 
>> I just received an XLi from e-bay. It unexpectedly has the Rubidium
>> standard, in addition to the GPS receiver 87-8028-2.
>> 
>> I have not yet determined if my 87-8028-2 is affected by the week 1024
>> rollover bug. After 12 hours it has finally transitioned from "SITE
>> SURVEY" to "TRAIM ACTIVE", but still not GPS locked.
>> 
>> Claude -- which exact Jackson Labs part did you use?
>> 
>> Unfortunately the X72 RUBIDIUM OSC is in FAULT state.
>> 
>> I am interested in any recommendations about what to do about the failed
>> rubidium. My next steps will be to check supply voltages and pull out
>> the 87-8028-2 to see which GPS module it has, but I was hoping it would
>> get GPS lock before I shut it down again.
>> 
>>> F18
>> F18 BOOTLOADER  192-8000
>>     SOFTWARE    192-8001
>>     FILE SYSTEM 192-8002V2-4
>>     PROJ REV #  2-4
>>     FPGA #      184-8000V65
>> 
>>> F72
>> F72 CLOCK PLL              LOCKED
>>     CLOCK STATUS           UNLOCKED    GPS PRI
>>     PRIMARY POWER SUPPLY   OK
>>     SECONDARY POWER SUPPLY OK
>>     RUBIDIUM OSC           FAULT
>> 
>>> F108
>> F108 OSCILLATOR CONFIG RUBIDIUM
>> 
>>> f60 b1 tracked
>> F60 B1 prn2 good tracked -153dBW
>> F60 B1 prn5 good tracked -154dBW
>> F60 B1 prn6 good tracked -155dBW
>> F60 B1 prn9 good tracked -157dBW
>> F60 B1 prn11 good tracked -154dBW
>> F60 B1 prn12 good tracked -154dBW
>> F60 B1 prn13 good tracked -196dBW
>> F60 B1 prn19 good tracked -162dBW
>> F60 B1 prn20 good tracked -154dBW
>> F60 B1 prn25 good tracked -156dBW
>> F60 B1 prn29 good tracked -156dBW
>> 
>>> f60 b1 current
>> F60 B1 prn2 good current -154dBW
>> F60 B1 prn5 good current -154dBW
>> F60 B1 prn6 good current -155dBW
>> F60 B1 prn9 good current -158dBW
>> F60 B1 prn11 good current -153dBW
>> F60 B1 prn12 good current -155dBW
>> F60 B1 prn20 good current -154dBW
>> F60 B1 prn25 good current -157dBW
>> F60 B1 prn29 good current -156dBW
>> 
>> Mark
>> 
>> 
>> On 11/25/21 5:45 PM, va2hdd at ebox.net wrote:
>>> 
>>> 
>>> Hi Martin.
>>> 
>>> In my XLi the GPS is in option bay 1.
>>> 
>>> As far as I know you can put it in any free option bay, you will
>>> configure it in software at start up.
>>> 
>>> In my case I had to replace the GPS receiver that was on the 87-8028-2
>>> option card, there was a week 1024 rollover bug issue on it.
>>> 
>>> Personally I would take the time to test it with an antenna, as the late
>>> production units have a more recent GPS receiver card that has no
>>> rollover bug.
>>> 
>>> In my case I used the Jackson Labs replacement board, and I warmly
>>> recommend it, it works flawlessly.
>>> 
>>> Have fun with your XLi !
>>> 
>>> Claude VA2 HDD
>>> 
>>> On 2021-11-25 16:41, Martin Flynn wrote:
>>>> Picked up a Symmetricom XLi with two A/C supplies and two empty slots.
>>>> 
>>>> Question #1
>>>> Is there a preference which of the two empty slots the GPS C/A
>>>> Receiver (87-8028-2) is placed in?
>>>> 
>>>> Question #2
>>>> 
>>>> Anyone have slot covers sitting around?
>>>> 
>>>> Martin
>> 
>> --
>> Mark G Thomas <Mark at Misty.com>, KC3DRE
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