Etrex Vista losing maps

[valkyrie]

On my last two rides my Etrex Vista HCx has lost its maps. What happens is -

1. I load a route and a track into the GPS the night before the ride. The display looks normal (metro maps plus contour lines).
2. Start the ride - everything looking OK.
3. At some random point the Route decides it needs to recalculate and then I notice that I've only got basemaps and the circle round the pointer has a radius of over 100m.
4. If I turn the GPS off and on again it's back to normal. For an hour or two, then it goes again.

I've not got a clue what's causing this, anyone got any ideas? I thought it might be a bad connection to the SD card but the tracklog from both days is perfect.

[Wowbagger]

I've had this occasionally, but it's been pretty rare. I put it down to one of those unidentifiable computer problems which is usually cured by turning it off and then back on again.

[Feanor]

Are the maps on an SD card?
Could it be an intermittent bad connection to the SD card caused by vibration / cosmic rays / lunar gravity / etc?
Perhaps try another card?

[frankly frankie]

On my last two rides my Etrex Vista HCx has lost its maps.

I have seen something similar.  Very ocasionally.  See Wowbagger above.

3. At some random point the Route decides it needs to recalculate and then I notice that I've only got basemaps and the circle round the pointer has a radius of over 100m.

I suspect that may happen in the reverse order - first the maps are lost and that immediately triggers a recalculation.
Otherwise - well you can turn recalulation off, it's a pretty unhelpful feature anyway (on a bike).

I thought it might be a bad connection to the SD card but the tracklog from both days is perfect.

I think it must be the card connection.  A lot of tracklog (well over a days-worth) is buffered in memory so even with a very intermittent connection that would probably still get archived to card OK.

[valkyrie]

Just opened the battery compartment to look at the SD card and the card was already in the sprung outwards position. Guess I should have looked in there first , though I still can't see why losing the SD card connection causes the positional accuracy to go to pot.

Doing the Rivers, Lochs & Glens 200 tomorrow so I'll find out then if pushing the card back in has solved it.

[Von Broad]

Just opened the battery compartment to look at the SD card and the card was already in the sprung outwards position.

Yes, I've had this a few times, although always with the card still in the correct position but losing a secure contact somehow. Switching the unit off, taking the card out, putting the card back and switching the unit back on have always cured the problem. I have just tried switching the Garmin off and back on again, but it's never resolved the problem, it's always a bad connection.

It's another reason why I always like running exclusively from a track, as that alway seems to remain visible and constant despite the maps disappearing.