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Step 4Unscrew the button panel
You don't have to unscrew the button panel for the fix I made, but it's easy to do and you can see the likely cause of the problem and another possible fix.
Remove the two screws that hold on the button panel. Underneath you can see the connection to the battery is made through a press-fit against the circuit board. See the 3rd image, where i've highlighted the battery case terminals and the contacts on the circuit board that they press against. The first time I had the problem with the GPS, I tried fixing it by slightly bending the battery case terminals where they poke out of the white rubber seal, to make sure they were pressing hard on the circuit board. This fixed the problem for about a month, so I concluded this was the cause of the problem.
So, we've got two possible ways to fix the problem: (1) fix the press-fit connection so that it never vibrates open, and (2) make it so that even if the press-fit vibrates open, power is not lost.
I decided to do #2: by adding a capacitor to the GPS power input, you can make it so that it doesn't care if there is a momentary loss of power during a hard shock. as long as the power connection is solid when the unit is not vibrating, this technique will work.
Lets momentarily consider how we might do #1 though: basically, by soldering the battery case terminals to the circuit board. This is a bit tricky to do because of the bottom-side connection, and because if the circuit board is moved at all the buttons won't work anymore. but i think it is possible with some care, probably the best way would not be a direct solder joint but to attach a thin wire between the connections and possibly melt the case plastic enough that the wire can be embedded and the circuit board is still flush on the mount.
Remove the two screws that hold on the button panel. Underneath you can see the connection to the battery is made through a press-fit against the circuit board. See the 3rd image, where i've highlighted the battery case terminals and the contacts on the circuit board that they press against. The first time I had the problem with the GPS, I tried fixing it by slightly bending the battery case terminals where they poke out of the white rubber seal, to make sure they were pressing hard on the circuit board. This fixed the problem for about a month, so I concluded this was the cause of the problem.
So, we've got two possible ways to fix the problem: (1) fix the press-fit connection so that it never vibrates open, and (2) make it so that even if the press-fit vibrates open, power is not lost.
I decided to do #2: by adding a capacitor to the GPS power input, you can make it so that it doesn't care if there is a momentary loss of power during a hard shock. as long as the power connection is solid when the unit is not vibrating, this technique will work.
Lets momentarily consider how we might do #1 though: basically, by soldering the battery case terminals to the circuit board. This is a bit tricky to do because of the bottom-side connection, and because if the circuit board is moved at all the buttons won't work anymore. but i think it is possible with some care, probably the best way would not be a direct solder joint but to attach a thin wire between the connections and possibly melt the case plastic enough that the wire can be embedded and the circuit board is still flush on the mount.
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Jan 17, 2009. 9:32 PMWayne az
says:
You could fix the #1 vibrating open problem by using silver conductive epoxy. With screws and conductive epoxy, it would take a lot of abuse. The downside is it would be damaging to remove the board from the batteries again. I'm taking mine apart now because the battery clip flexed so many times it cracked at the "V" apex. If I had epoxied the unit together earlier, I could not do that.
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