gps-kitesurfing
It has been suggested that this forum be used to gauge the number of people experiencing lock up problems with the GT-31.
It happened to me recently.... even though I had upgraded to the lock-up fix firmware (V1.3B1132T) on my unit.
It is proposed to use GT-31 units for recording individual's speeds during Weymouth Speedweek 2010...so how reliable are these units?
For myself I know of my own unit and also Pete Young's (although he is still running with an earlier firmware).
Had a lock up last week on my gt31... no response from any key...   let it run itself out of battery and it seems to have started up ok... but no data saved from the session at all...
Luke also had one do the same a while back...
Be great to track down why they are doing it!
I wonder if it is down to variations in peoples routine (i.e. what they do after switching it on). I've recorded around 80 sessions on my GT-31 (windsurfing, cycling, walking) and not had the misfortune of it locking up.

What do you guys do after switching it on? My general routine goes like this:

1) Switch on the GT-31 and place it on my dashboard whilst getting changed.
2) Once I'm changed it will have a fix on the satellites and is displaying the speed
3) Clear old data from trip meter, speed genie and data logger (using Misc -> Delete -> Del All)
4) Go back to speed genie and lock the keypad, ready to sail

After sailing:

1) Unlock the keypad
2) Save speed results and data logger to SD card (using Misc -> Save To Card -> Save All)

Do you guys ever lock the keypad before obtaining a satellite lock, before the SD card is detected or before it says "new file"? I suppose something else that could affect things is the type of memory card and whether the battery is getting low.

When the device locks up, does the data logger contain the session so that it can be saved to card once the device has been run flat and restarted?
GT31 operates in a wide range of temperature and humidity and its electronics is exposed to condensation. Condensation occurs when GT31 case is open in a hot/warm environment (sun-heated car for example), closed and then used in the cold water.

I haven't heard about any sensitive electronic device on Earth that is guaranteed to work in the condensing environment, so GT31 reliability is actually quite impressive. Considering its challenging operating environment - GT31 is actually more reliable than Microsoft Windows...

 The only situation when I experienced a "lockout" was after some salt water managed to get inside the GT31 case. Once some salt gets inside the case, condensation can cause problems, because condensed water dilutes the salt residue and becomes conductive.

Since there is always a possibility of condensation and/or leak inside the GT31 case, it is very important to "DRY" the unit when it is not in use. To dry GT31, I store it with its door open in warm and dry environment and avoid sudden temperature changes.

The only obvious shortcoming of GT31 that I can see is its non-waterproof case.
The GT31 case needs to be re-designed.
See http://picasaweb.google.com.au/mt.best.net/GT31WateproofEnclosure#slideshow/5433881124903064642 for my prototype effort.

In the meantime, while we still wait for a "lockout" situation/sequence that we can actually reproduce to diagnose the problem, my advice is

1. Dry GT31 thoroughly with door open when it is not used

2. Prevent water penetration and/or condensation when using GT31. Matthew Robertson uses "gardening water crystals" in his hard-aquapack to catch any water/moisture that manages to get inside. He bought a few-dollar packet and told me that this packet could last him for ~20 years, because only a tiny amount is used for each sailing session.
Hey all,



I think the advice both Mike and Tom have provided is worth heeding.




From the experience of some devices returned to me throughout the last year or so I believe the issue relates to the data logging.  I have therefore updated one of the gps support pages on my site reflecting the new advice.




Norm, I think you got the gist of it from my mail last week but again be sure to check-out the updated information on the site as follows...




Link: http://rippers.rikswindsurfing.com/forum/viewtopic.php?f=2&t=63




Best wishes,




Rik

Rik said that he observed lockouts to be associated with cold weather.

The colder the weather - the more likely is the possibility of condensation inside GT31, when you take it sailing from a "warm" environment. The larger the temperature difference between warm storage and cold use of GT31 - the more likely is the internal condensation. This seems to explain Rik observations.

We should have in mind that electronics tends to be more reliable in colder environment...

Tom


My unit is now fully charged and ready for its next outing....the only difference I shall make is to bag it in a sealed freezer bag before sealing it in its aquapac.

I was disappointed by the lock up, but did find some very useful advice from the seabreeze forum:

http://www.seabreeze.com.au/forums/topic.asp?TOPIC_ID=61603

Mike...I pretty much follow the same start up procedure as you and when the unit is not in use it is kept indoors and out of the bag.
Rik...Yes took note of your advice...particularly the full battery discharge from time to time...thanks very much for that.

Until confidence rebuilds and conditions look promising, I shall probably have both the Gt-31 and Garmin 201 in use!

Norm
Tom...forgot to say I do have some of those gardening crystals so will put them in the with the unit!

The warm damp air/ cold water use makes sense but the lock ups don't just happen in the winter or unique to the UK....also for myself my unit is always stored in the dry indoors, bagged in its aquapac before leaving the house and then only comes out to set it for sailing and again later for switching off.
Tom - I do know how much you contributed to the universal adoption of the GT-31...thanks for that.  It's white man's magic to me!
Tom.. while  the navi experts might not be able to replicate the lockouts they are an ongoing reliability problem...
I have had another unit  lock half way through a session this week... and Gavin here had similar several weeks ago...  in my case  this is the third time now....   my aqaupacs are kept in very dry conditions with crystals inside.... I never handle the gps with wet hands ...  so they have never to my knowledge come into contact with any water other than humidity in the air...   when the unit locks up  in both cases the sbn file has not registered any of the session ...ie  a 0kb file   and the sbp file in datalogger has ended at the start of the session.. even tho sailed for an hour or so before lockup ...  in all cases I have let the unit fully discharge then charged and they have  turned on ok...   but makes it hard to trust them anymore

In response to other comments above I am also careful about the routine to turn on and then holding  ensure that the speed genie has set up and started registering before  holding down the toggle to lock it....(found in the past that if toggle lock applied before genie is reading speed the track file can be lost)
Despite your comment Tom that the navi is more reliable than windows...  we seem to be having more and more lockups! 

Also the lockups appear to just occur at random times...  ie simply sailing along a run and freezes ...not linked to turning unit on or off at all...
Chris



 
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