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:

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 BOOTLOADER  192-8000
    SOFTWARE    192-8001
    FILE SYSTEM 192-8002V2-4
    PROJ REV #  2-4
    FPGA #      184-8000V65

F72 CLOCK PLL              LOCKED
    CLOCK STATUS           UNLOCKED    GPS PRI
    PRIMARY POWER SUPPLY   OK
    SECONDARY POWER SUPPLY OK
    RUBIDIUM OSC           FAULT

F108 OSCILLATOR CONFIG RUBIDIUM

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 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@ebox.net wrote:

--
Mark G Thomas Mark@Misty.com, KC3DRE

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@lists.febo.com> wrote:

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

Hi;
As a M12 replacement the Jackson Labs replacement works great.
Make sure you check the output voltages on the power modules next to the X72 and make sure they are working before replacing the X72. I know the X72 are not as common as they have been, if your XLI issue is the X72 I have spares I can sell. Just contact me off list.
Good luck with the XLI they are nice boxes.
Cheers;

Tom Knox

SR Test and Measurement Engineer

Phoenix Research

4870 Meredith Way Apt 102

Boulder, Co 80303

Formerly of:
357 Fox Lane
Superior Co 80027

303-554-0307

actast@hotmail.com

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From: Bob kb8tq via time-nuts time-nuts@lists.febo.com
Sent: Wednesday, September 21, 2022 2:59 PM
To: Discussion of precise time and frequency measurement time-nuts@lists.febo.com
Cc: Bob kb8tq kb8tq@n1k.org
Subject: [time-nuts] Re: Symmetricom XLi question

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

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com

Mark,

My XL took a good 24 hours to lock after it had been unpowered for who knows how long and moved half way across the country. It also has the 87-8028-2 gps receiver and was not affected by the week 1024 rollover.
It’s a shame if the rb is dead; as many have said there’s no information on them.

If anyone has one to let go of, I am looking for an 87-8028-2 gps receiver for an XLi SAASM that I got without the receiver. A list member offered me one pre-pandemic but he  then seems to have gone silent.

Steve K.

I will agree with you Bob. But those are the best opportunities to
experiment and learn.
With a bit of luck he can find the 15 pin diagram and with a drop more luck
the lamp signal (Or not). There is always the old open it up and see if the
lamp ignites. Only taking apart as little as possible to get in. Thats
still a lot. If there is light then it gets really messy reverse
engineering the photocell out and temp controllers RF etc. Since winters
coming what a great project. Humor intended.
But the good news is there is a possible chance to recover it.
Regards
Paul
WB8TSL

On Wed, Sep 21, 2022 at 4:59 PM Bob kb8tq kb8tq@n1k.org wrote:

Hi,

I now have two 87-8028-2 boards, both with Furino GT-8031H on them, both
which get stuck for days UNLOCKED, in state "TRAIM ACTIVE". I have ordered
Jackson Labs M12Ms to upgrade them.

F119 B1:
GPS PART NUMBER 87-8028-02
SOFTWARE 230-01510-04v1.20
FPGA 184-8024v1
GPS STATUS UNLOCKED
GPS ANTENNA OK
GPS ACQUISITION STATE: TRAIM ACTIVE

This might mean more XLi units showing up, and cheaper, on e-bay, if
these GPS units have hit some other rollover and no longer work at all.

Info in this article was helpful, as it includes instructions for
displaying the web usernames and passwords if a prior owner changes them:
https://www.eevblog.com/forum/testgear/symmetricom-xli-license-hack/

Mark

On Wed, Sep 21, 2022 at 04:48:52PM -0500, Steve Krull via time-nuts wrote:

--
Mark G. Thomas Mark@Misty.com, KC3DRE

My S300 Furino GT-8031H rollover on September 18 at 00:00 UTC.  There is a
Microsemi article that said that those GPS receivers survived the 2019
Number of Week rollover but the internal representation would rollover now.

I ordered Jackson Labs units to replace them and I really like them.  Very
solid design with superior features.

Todd

On Tue, Sep 27, 2022, 17:20 Mark G Thomas via time-nuts <
time-nuts@lists.febo.com> wrote: