My Quest 1 (243mb version) doesn't seem to want to hold its charge anymore. I guess it is about 3 years old soit may have reached the end of its life.
There's a rubber gasket that seals the split in the cases, so long as you get that lined up properly when you reassemble your Quest I don't think you'll have a problem.
I've had both my Quest and my 2720 apart and haven't, as far as I can tell, had any problems with either in respect of water ingress to date.
Obviously if your GPS is still in warranty then Garmin is your first port of call otherwise I imagine it would be an exchange unit at the regular price which IMHO would make the DIY option the only viable way. Of course with the exchange unit you do get up to date mapping which should be factored in if you need it.
There's a rubber gasket that seals the split in the cases, so long as you get that lined up properly when you reassemble your Quest I don't think you'll have a problem.
I've had both my Quest and my 2720 apart and haven't, as far as I can tell, had any problems with either in respect of water ingress to date.
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I know that some manufacturers get clever when things are supposed to be waterproof, but with my limited tech ability even I should be able to deal with a gasket.............. maybe.