Garmin has advised us that the following procedure should work for
all receivers which might have problems with the EOW rollover:
1) Turn on your receiver.
2) Place it into AUTOLOCATE MODE. Note: No other mode will do. Select a country won't do.
3) Place the GPS in an outdoor location where it has a full sky view.
4) Within an hour it should get 3D lock.
5) Leave it outside for as long as possible up to about 12 hours so it can collect ephemeris data from all of the SVs. (If you stop in the middle, it is OK, but the GPS will have to collect the other data later which is just fine too.
After you have done this, most Garmin GPS receivers should work just fine. Yep.. Those Garmin guys did not do it perfectly in their older receivers. Still, the fix is pretty simple and easy to do. PLEASE let me know any Garmin receivers that this DOES NOT work with. Please include the firmware revision for the unit.
Click HERE to send Email to: Joe Mehaffey
Garmin has provided some additional comments with respect to the instructions above.
I have been watching the newsgroup and here are some mistakes people are making with respect to trying to get their older Garmin units recovered from the EOW rollover.
1) People may not be getting the unit into autolocate correctly. I saw one post yesterday (GPS 65) that suggested the user was powering on the unit THEN pressing "0." If I am correct, somehow it was not clear that he needed to firmly hold the "0" key before powering on...
2) People are not waiting long enough. It takes 12.5 minutes for all of the almanac to be broadcast by the satellites. It can take MultiTrac 15-30 minutes just to find a satellite in AutoLocate. As such waiting an hour is not unreasonable. I am 100% confident that we can get all MultiTrac receivers going again by this method. Note the method may have to be repeated if satellites are "dropped" for whatever reason.
3) Using the master clear is RISKY. Crystal oscillators drift over time. The GPS receiver retains the oscillator information so that it can acquire when it is turned on. If this information is cleared it could take much longer to acquire in the first place. Now I know that some users are reporting success with this method but its like diving into murky water with your arms at your side (my kids report to me that this is called a "dead Taylor"). We tried this method on an old GPS 90 and, because the drift was so far out of spec after 6 years the unit had to be re-calibrated in a temperature chamber before it would acquire again.
On the other hand, we used an old GPS 38, turned it on with fresh batteries,
DID NOT use
autolocate mode. In 4 hours the GPS 38 had healed itself through patiently looking for satellites. Note we
tried to make this unit the "worst case" scenario by loading it with the most recent almanac (week 1023) and
trying to use the unit after roll over (no autolocate).
Truthfully this situation is no worse than a user throwing his GPS
in a drawer for 6-9 months and then trying
to use it again. Similar things can happen if the alkaline batteries are removed for many months. Its just part
of how GPS works. 12 channel units are much more suited for the challenge.
Garmin Engineering Department
In all of my conversations, I am recommending that the customer with
a GPS 55 perform the master clear
sequence. We never recommend master clearing a GPS 38, 40, 45, 45XL, 89, 90, or 120. However, the GPS 50, 55, 65, 75, 95, and 100 will generally operate normally after a master clear (Power ON while HOLDING CLR).
Basically, there are three EOW recovery options people should consider with these older model GPS receivers:
Switch-on while holding the PAGE key, this will need to be done any time you switch the unit on until the 20th September. This method does not affect your user data.
Download and use application available from our website that resets the date in the GPS. This method does not effect your user data.
Switch-on while holding the MARK key, this performs a master reset and re-enter an initial position then leave it receive. This only needs to be done once, but deletes all user data.
The GPS can take 30 to 45 minutes to acquire after any of these methods.
Garmin Engineering Department