Thread: About 37xx converted to 34xx satellites reception accuracy

Both Angelo and isg have converted units. No point trying in mine as i have acceptable accuracy with no value for part number, only showing Rev: 01. Maybe problem is elsewhere or a combination of factors?

...sorry for my english...
MY EXPERIENCE

i've a 37>34. When it was 37 reception was 3 - 5 meters about and when 34xx bad reception 8 - 15 but not important accurancy but quality of signal. In fact quality was very poor, bars of satellities go up and down in secret menu so when i navigate along a street car jump from my route to another and in city this is a problem for me. i'do many test thanks to all but without good solution. Last week i've do a travel (2000 Km about) and i've see that accuracy is from 7 to 20 meters, depending also the weather and mountain where i was so today i've decide to return to 37xx for test accurancy and looking for files differents. in 37xx accurancy was again good 4 -6 meter in my balcony (no good place) so i have clean hard drive of nuvi (folders and files not important) for see the different from files 37xx to files 34xx. then iìve flash to 34xx again with firmware 3.50, then Caty's solution "convert 37xx34xx.zip" and then Lolypop000's solution "region 139..."
Accuracy was very good after 10 minutes, about 4 - 6 meters but thing for me important is that blu bars of satellities quality are stable. Not up and down. I've not try my "new" nuvi on the road but i've see that accuracy is very different. So i've try to update to last firmware for see the differents and now with firmware 7.6 accuracy is good. I've see accuracy until 8 meters after 5 minutes then i've stop and go inside my room because out is to much cold!!! but blu bars don't go up and down and accuracy is stable. repeat that i've not do a on the road test but tomorrow i think yes. then i replace right files (not systems files) with webupdater and my backup (language, text, asr, keyb) and now it's ok. Tomorrow i write if this is a good solution or only a way to spend 1 day with our nuvi

If you have tomorow good accuracy, then please write tutorial of your step and create pack with file that you use for this test

I appreciate all of the effort, from all of you that are trying to solve the accuracy problem. Hopefully we will succeed in solving it. Respect to all effort inputers and thank you for the time you are spending in solving the issue

Loly, I installed "Part Number 006-D2617-00 Rev. 0A" yesterday, but not noticed alterations in precision in my measurements, but they were only statics (I owe a dynamic evaluation). However I noticed a curious thing: after the installation of the patcher the GPS lost all satellite almanac and began to tune from scratch. In short, this region and this "part number" has to do with some function related to tuning of satellites. It remains to discover which more "part number" would related with this..

As promised I am by posting videos and photos of measurements made ​​with the precious help of Tadferreira which has also a 3790 original. The first film was made more than two weeks and the last few days. If already it is not necessary to prove the accuracy of major differences between the original and modified at least should serve as a document and even convincing to those still a little skeptical, lol .. The important thing is that they are dynamic measurements, that really matter.
Another day, traveling in a large avenue, the GPS indicated that I was on the road side while I was on the main road. 15 or 20 meter accuracy can also be important in navigating urban, since the gps can not recognize whether we have entered a wrong street as immediately as would be desirable, ie, is it possible to use this firmaware, but he leaves, no doubt, very to be desired. If I was a professional driver, I do not would use this firwmare, would keep the same original.
Sorry for the "Pro" quality..





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Angelo, there's absolutely no longer any doubt that some coverts have unacceptably poor accuracy. Nice comprehensive tests, many thanks to you and Tadferreira for all your time and trouble. But which units suffer worse, and why? This has to be somehow related to certain 37xx hw being less/more compatible with 34xx gps fw. Is your convert maybe a later production model, ie S/N 1W80xxxxx, where first x is not 0?

Originally Posted by Neil

..But which units suffer worse, and why? This has to be somehow related to certain 37xx hw being less/more compatible with 34xx gps fw. Is your convert maybe a later production model, ie S/N 1W80xxxxx, where first x is not 0?

Neil, a creeping logic would tell us that the latest 3790 should be more compatible with the 34xx, but for some reason may be that they are more compatible with older hardware or firmware, as you suppose, but we have to test and prove effectively these assumptions. As the conditions of testing are many different, different continents, local and criteria, it is not easy to know. The way is to perform comparative tests with criterion. In my view the most reliable way to compare, whenever possible, is with a 3790 not modified, side by side.
It seems that the level of accuracy among f modern Garmin GPS is very similar, enabling even a good comparison parameter if we do not have a 3790 original. My 3790 is recent, serial number 381xxxxxxx (sorry, forgot the rest, lol) PCB: V8 8GB 035 DA TC GM. The 3790 of TadFerreira is s/n 380xxxxxxx.
All possibilities are valid, somehow we will get there ..

Originally Posted by angelozip

Neil, a creeping logic would tell us that the latest 3790 should be more compatible with the 34xx, but for some reason may be that they are more compatible with older hardware or firmware, as you suppose, but we have to test and prove effectively these assumptions. As the conditions of testing are many different, different continents, local and criteria, it is not easy to know. The way is to perform comparative tests with criterion. In my view the most reliable way to compare, whenever possible, is with a 3790 not modified, side by side. .......

Agree that side-by-side contemporaneous testing is the only valid way. Yes, logic would seem to dictate that later hw would be more compatible, but my convert is an early model and has comparatively good accuracy. That is the reason why I am prepared to revert my convert to 3790, and convert my virgin 3790 to 3490 to see what happens with the accuracy on it. But it may be more important to retain a totally original 37 as a known standard.

It seems that the level of accuracy among f modern Garmin GPS is very similar, enabling even a good comparison parameter if we do not have a 3790 original. My 3790 is recent, serial number 381xxxxxxx (sorry, forgot the rest, lol) PCB: V8 8GB 035 DA TC GM. The 3790 of TadFerreira is s/n 380xxxxxxx.
All possibilities are valid, somehow we will get there ..

Originally Posted by catymag

mine is 381xxxxxxx

Umm, so it appears that not all 3790 Serial Numbers are in the format of beginning with 1W8 etc as my 2 are. Oh, well another shaky theory of mine 'out the window' maybe. However, it appears TadFerreira's is older than both Angelo's unit and Caty's unit. Another 'out of left field' thought of mine, both Caty & I have converted and reconverted several times. But how could that be related to accuracy ...

I hope Loly's doing his Swan on Pond act and working hard undercover again.

mine is 381xxxxxxx