Cambridge 302 and GPS-NAV owners – IMPORTANT NEWS

FYI: I sent my 302 in last Saturday.

Gary repaired and calibrated the unit very quickly and it will most likely return ship to me by the end of the week! Wow, I'm impressed! Great service and fast turn-around at an excellent price, thank you Gary!

If you own a Cambridge 302 or GPS-NAV and, like me, would like to get a few more seasons out of it before upgrading, this is an absolute no-brainer!

Brian

The Garmin GPS-25 manual indicates the internal battery is a rechargeable Lithium with a capacity of about 180 mAh. It also says the load on the battery when the board is unpowered is 50 microamps. There is no way to see what the state of charge is on that little battery. Or how long it takes to charge it up when the board is powered. A fully charged battery is good for about 5 months. If you discharge the battery completely, the memory and real time clock will quit and you are back to 19.5 years ago again with no way to fix it other than sending it back again. So don't go too far between the new battery install and using the gps again.

My 302 went back to 1995. My GPS-NAV clock had drifted off by 3+ minutes, it did a "search the sky" when I powered it up last week and came up with the correct time.

-Dave

On Wed, 03 Dec 2014 20:08:56 -0800, Dave Leonard wrote:

The Garmin GPS-25 manual indicates the internal battery is a
rechargeable Lithium with a capacity of about 180 mAh. It also says the
load on the battery when the board is unpowered is 50 microamps. There
is no way to see what the state of charge is on that little battery. Or
how long it takes to charge it up when the board is powered. A fully
charged battery is good for about 5 months. If you discharge the battery
completely, the memory and real time clock will quit and you are back to
19.5 years ago again with no way to fix it other than sending it back
again. So don't go too far between the new battery install and using the
gps again.


Right, the manual says "up to six month charge" for that battery.
Extremely marginal for the way we commonly use the units. Since the
firmware worked correctly without battery backup for roughly the period
2005 +- 10 years, it covered up bad batteries, or good batteries that
just had been discharged. Without new firmwware to kick the can down the
road again, it's going to be on an ongoing headache.

Newer systems use a 13 bit integer instead of 10 to keep track of the
week, doubt there's any chance that would ever be retrofit into the units.

-Dave

I wonder if the affected FR manufacturers could add a mod to detect a timestamp prior to "now" and munge it to the current epoch?

Would FAI accept this solution?

-Tom

On Wednesday, December 3, 2014 10:55:08 PM UTC-8, David Kinsell wrote:
Newer systems use a 13 bit integer instead of 10 to keep track of the
week, doubt there's any chance that would ever be retrofit into the units.

On Thu, 04 Dec 2014 18:08:27 -0800, tom wrote:

I wonder if the affected FR manufacturers could add a mod to detect a
timestamp prior to "now" and munge it to the current epoch?

Interesting idea, but quite hypothetical when it comes to Cambridge.

Garrecht Avioncs seems to have source code for the GPS module, and
intends to provide a fix in that code for their Volksloggers. It should
be straightforward to add another 20 years of life that way.

As the details of the problem have come out, it's become clear that the
fix being applied to Cambridge units isn't very good and won't make them
as reliable as they were prior to November. Probably makes more sense to
just go buy a Nano or something similar if you need to replace the
logging capability.

-Dave

Now you are trashing all C302s. The all purpose instrument.
Logger. Vario. Flight director. Navigation instrument.

On Thursday, December 4, 2014 9:49:54 PM UTC-5, David Kinsell wrote:

it's become clear that the
fix being applied to Cambridge units isn't very good and won't make them
as reliable as they were prior to November.
-Dave

Oh my!

To all Model 10/20/25,302A and 302 owners who have been following this topic, were happy with there instrument prior to this issue and want to keep using these devices(that's thousands of flight computer/recorders)you can send your recorder to a qualified equipment tech who will replace the 3v re-chargeable battery internal to the Garmin Receiver, send appropriate commands to the Garmin Receiver to reset the date and re-seal the instrument. After that, you are good to go for MANY more years.

IF you do not use the instrument for greater than 5 months, then power the instrument overnight to re-charge the Garmin battery as CHEAP insurance. With a little extra care they are as reliable as they were--no better and no worse then prior to this issue.....Gary

On Friday, December 5, 2014 8:48:04 AM UTC-5, Soaring Tech wrote:
On Thursday, December 4, 2014 9:49:54 PM UTC-5, David Kinsell wrote:

it's become clear that the
fix being applied to Cambridge units isn't very good and won't make them
as reliable as they were prior to November.
-Dave

Oh my!

To all Model 10/20/25,302A and 302 owners who have been following this topic, were happy with there instrument prior to this issue and want to keep using these devices(that's thousands of flight computer/recorders)you can send your recorder to a qualified equipment tech who will replace the 3v re-chargeable battery internal to the Garmin Receiver, send appropriate commands to the Garmin Receiver to reset the date and re-seal the instrument. After that, you are good to go for MANY more years.

IF you do not use the instrument for greater than 5 months, then power the instrument overnight to re-charge the Garmin battery as CHEAP insurance. With a little extra care they are as reliable as they were--no better and no worse then prior to this issue.....Gary

Thank you Gary for clearing this up.

Dennis

Originally Posted by David Kinsell[_2_]

On Thu, 04 Dec 2014 18:08:27 -0800, tom wrote:
[color=blue][i]
...

Garrecht Avioncs seems to have source code for the GPS module, and
intends to provide a fix in that code for their Volksloggers. It should
be straightforward to add another 20 years of life that way.


-Dave

Hi All,

1)
yes, we probably have a fix for the GPS25 modules, but it has to be confirmed working under all circumstances by a GPS simulator. This will of course take some time ...

2)
We do NOT have the sourcecode ...

3)
The only two solutions Garmin has officially suggested to us a

a) recharge the battery for 2 days and reinitialize the module by it's serial interface to a new date = obviously this only works for another 2-5 months.

Also, the rechargeable batteries inside the GPS25 also age with time - Garmin should know this. We got lots of new modules at beginning of the 2000s which were not able to hold their time and date for even 2 weeks.

b) replace module by GPS15 module.

For technical reasons, both solutions are not an option for us, thus we'll continue work on the firmware-patch, and at the same time on a software-only solution (new VALI-GCS files, maybe new VL firmware).



Good luck with the CAI solution.

On Fri, 05 Dec 2014 17:09:59 +0000, Georg Garrecht wrote:
[color=blue][i]
'David Kinsell[_2_ Wrote:
;892916']On Thu, 04 Dec 2014 18:08:27 -0800, tom wrote:

...

Garrecht Avioncs seems to have source code for the GPS module, and
intends to provide a fix in that code for their Volksloggers. It
should

be straightforward to add another 20 years of life that way.


-Dave
Hi All,

1)
yes, we probably have a fix for the GPS25 modules, but it has to be
confirmed working under all circumstances by a GPS simulator. This will
of course take some time ...

2)
We do NOT have the sourcecode ...

3)
The only two solutions Garmin has officially suggested to us a

a) recharge the battery for 2 days and reinitialize the module by it's
serial interface to a new date = obviously this only works for another
2-5 months.

Also, the rechargeable batteries inside the GPS25 also age with time -
Garmin should know this. We got lots of new modules at beginning of the
2000s which were not able to hold their time and date for even 2 weeks.


Yes, isn't it strange that when the problem first blew up in 1999, no one
suggested that merely replacing the battery was an adequate solution?
Yet now some people are claiming this is a "fix". It's a temporary Band-
Aid (rtm) that can fall off at any time. Probably when you're least
expecting it.


b) replace module by GPS15 module.

For technical reasons, both solutions are not an option for us, thus
we'll continue work on the firmware-patch, and at the same time on a
software-only solution (new VALI-GCS files, maybe new VL firmware).


Ian seems to be using the GPS15. As you no doubt are aware, it requires
a physical adapter, has an even tinier battery, and is no longer in
production. New firmware for the GPS25, or the VL, seems to be the right
solution. Glad you're pursuing the issue so vigorously. Perhaps Garmin
could be coerced into doing new firmware if the proper level of
complaints were directed their way. They released new firmware for GPS15
in 2009, but I can't find any info on whether it would have the same
issue pop up in 2019, or some other date.



Good luck with the CAI solution.

Tnx, but I don't suffer from delusions that the 302 is some kind of great
navigational device like some people do. When mine dies, I'll just
replace the logging function with something better.

-Dave