Yet Another Cycling Forum
General Category => The Knowledge => GPS => Topic started by: Dave on 15 June, 2008, 06:28:52 pm
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OK. I'm getting really cheesed off with this now.
On the last three long rides I've done, I've spent more time looking at the screen of my Vista HCx that at the scenery, 'cos I have to keep checking that it hasn't switched itself off. AGAIN. >:(
I said 'randomly' in the subject, but I don't think it is. It's got something to do with speed and vibration. Hitting a single pothole won't switch it off, neither will riding over the wrong sort of road surface (like that thin layer of tar with a layer of grit thrown over it) fairly slowly.
But, hit a newly laid stretch of 'tarmac' or a rough downhill and I'm lucky to get it to stay on for more than a 30 secs at a stretch. AAAAAAAAHHHHHHHHHHH.
Smooth tarmac - it's fine, it'll run for for as long as the surface holds out.
So. What can I do? Someone on another thread mentioned an external battery pack, but I'd rather avoid that as I don't want to have to strap another box to the bike.
Anything to be done with the battery compartment, or (what I think is the real culprit) the lousy handlebar mount?
(Sorry. Bit long that. But I needed to rant.)
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Try:
putting some "shoo goo" on the mount to reduce vibration
I put some insulating tape on the mount to achieve the same effect.
Also, consider trying some different batteries; they aren't all exactly the same size.
Not had this problem with the Vista HCx though which has a more solid battery compartment cover.
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Since it sounds like a vibration issue, making the batteries more "firm" may help. If there is any give that allows them to move in their compartment, there is a slight risk of contact movement, and consequent brief loss of power. Some sort of material around the batteries may make things a bit snugger.
Depending on how electronically oriented you are, and how much space there is in the case, you could try and fit a largish capacitor on the bus to hold the power up when there is a slight discontinuity in the supply.
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This may or may not be relevant; the only time I've had this problem with my Vista Cx is when using 1300mah batteries.
Fatter 2700mah batteries make a much tighter fit and I've never had any spontaneous switch offs with them.
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It's a well known issue with Garmin units, both mine do it too. Maladict's advice is good.
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Thanks for all the advice.
Try:
putting some "shoo goo" on the mount to reduce vibration
What the heck is that?
I put some insulating tape on the mount to achieve the same effect.
As in, a strip in the flat, recessed bit of the mount?
Also, consider trying some different batteries; they aren't all exactly the same size.
Tried it with Hahnel, Uniross and Eneloop rechargeables (2500mAh though) and Duracells. No luck. I might see if I can get hold of some 2700s.
Not had this problem with the Vista HCx though which has a more solid battery compartment cover.
This is with a Vista HCx. Just over three months old.
I'm going to try a liberal application of cut up bits of foam and see if that helps...
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Thanks for all the advice.
Try:
putting some "shoo goo" on the mount to reduce vibration
What the heck is that?
I put some insulating tape on the mount to achieve the same effect.
As in, a strip in the flat, recessed bit of the mount?
Also, consider trying some different batteries; they aren't all exactly the same size.
Tried it with Hahnel, Uniross and Eneloop rechargeables (2500mAh though) and Duracells. No luck. I might see if I can get hold of some 2700s.
Not had this problem with the Vista HCx though which has a more solid battery compartment cover.
This is with a Vista HCx. Just over three months old.
I'm going to try a liberal application of cut up bits of foam and see if that helps...
Shoo goo is some kind of rubbery gluey stuff. Jo Wood recommended it for this purpose. Just a wee bit in the flat, recessed bit of the mount. I did the insulating tape thing, exactly where you said, it did stop it rattling about in the mount.
Another option is to put some shoo goo or similar in the case to keep the batteries from moving about.
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Shoo goo is some kind of rubbery gluey stuff. Jo Wood recommended it for this purpose. Just a wee bit in the flat, recessed bit of the mount. I did the insulating tape thing, exactly where you said, it did stop it rattling about in the mount.
Another option is to put some shoo goo or similar in the case to keep the batteries from moving about.
Hmm. OK. Looks interesting, I'll give it a go. Thanks.
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[Slightly OT: My recently acquired Vista HCx exhibited screen freezing at randon times after I'd had it about 2 days. It was not a vibration issue as it could happen when not moving.
I sent it back for a replacement - the supplier said this occurred with about 1 in 100 units. The new one has not done this at all after about 300 km.]
Re the vibration issue:
The batteries I use (Ansmann 2850 mAh) are an extremely tight fit in the device and I think it would take an extreme shock to move them.
However, I have tightened the fit of the device in its bracket by simply using about 3 rectangles of insulating tape along the outer face of the male part of the bracket (on the device). It does not rattle at all. Personally I'd avoid shoe goo as it is messy.
Also I use an Acor bar extender, which in itself probably isolates the HCx from road shocks. I use the oversize brackets (although the Acor is not oversize at the device end) and strips of rubber to pack it out. All in all it is pretty well insulated from road shock.
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My recently acquired Vista HCx did this after I'd had it about 2 days. It was not a vibration issue as it could happen when not moving.
I sent it back for a replacement - the supplier said this occurred with about 1 in 100 units. The new one has not done this at all after about 300 km.
That's interesting. I'm pretty sure that my problem is vibration related. It's never (AFAICR) switched off when not moving and smooth roads don't cause the problem. I gave it 150km of testing today :)
I'll slap some insulating tape on the bracket and see what happens.
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The Etrex series of units is known for this fault.
The cause can be two-fold. One cause could be that the batteries are a little "loose" and slightly bigger batteries of a little padding can help.
However, in my experience, this is NOT the major cause and the problem lies not inside the battery compartment, but in connections between the battery compartment and the printed circuit board behind it.
That some batteries work better than others is a function of battery case distortion and weight rather than intermittent battery contact.
The ultimate cure is to do a little surgery on the unit (if it is out of warranty) and either solder little fly leads between case contacts and PCB OR add in a little 10uF tantalum capacitor on the PCB (or both). The way to do the latter with the GPSMap 76Cs is detailed on the web (http://www.instructables.com/id/Shock-Proof-your-Garmin-GPS/) - the procedure for the Etrex is similar but involves a littler more in the way of surgery, removing the rubberised case edge, etc.
I did hack my old original etrex some time ago with success but my current HCx is still in warranty so I am using a home brew foam padded handlebar mount for it in the interim.
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Sadly, that kind of surgery is way beyond what I'm capable of. But the link has given me some ideas for fettling a replacement mount...
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My suggestion on this thread worked for me
GPS purchasing advice please (http://yacf.co.uk/forum/index.php?topic=3444.msg57002#msg57002)
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An oversized handlebar mount on non-oversized bars helps a lot - the extra thickness of rubber seems to make all the difference.
Use of lithium (primary) cells helps a lot - but might be seen as expensive. They are half the weight of NiMHs and so reduce the battering-ram effect. (And they do last 50+ hours.)
But the root problem lies on the circuit board, not in the battery compartment - you can't fix it without opening the unit and compromising the waterproofing. Garmin really should have fixed this well-documented problem by now, especially since the H series uses a totally different chipset to previous models.
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A crude fix to the PCB contact issue is to use a soldering iron to melt the plastic around the rivets - heat the rivets, as the plastic melts push them deeper with the tip of a screwdriver, remove iron and allow to cool (inadvertently discovered this worked while soldering a capacitor across the battery contacts). Although this could in theory affect the immersion-proorfing, as the contacts are inside the battery compartment at the top they won't get wet unless the unit is immersed in water for a while (the battery compartment is not rated waterproof to this level).
One tip to tell which issue it is - loose batteries or PCB contacts - is to remove the internal batteries and try running with an external pack. If it still powers off with this setup, it's the PCB contacts (and you may have the loose battery issue too).
I don't believe their claim it only affects 1 in 100 units though. The problem has affected 3 out of 3 units here (two eTrex Summits bought in 2006 and 2007, and an eTrex H bought in May 2008).
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Similar problems with a bog standard eTrex (the yellow one).
I've given up trying to fit bits of insulating tape or the like. It worked for a short while but after enough time out in wet weather it soon starts wobbling in the mount and turning itself off.
The battery size does help but doesn't cure it all. Mine still turns off with tight fitting Ansmann 2700mAh batteries. Smaller Energiser batteries would have the unit turning off much more often.
On the Severn Across 400 it was fine for the first 100km but after leaving Stow, on poorer road surfaces, it was turning itself off every 20 seconds or so. I soon got bored of this and just ziptied it to the bars (in its mount), this held it all the way to the finish.
I've now sourced a reusable ziptie to hold it in place. Yes it obscures part of the screen but there's no important data displayed on the bit it obscures so I don't care.
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The "1 in 100" referred to the problem I had, which was freezing up for no reason whether moving or not. Sorry for mixing in that separate issue, I should have made that clear.
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My eTrex started switching off a lot because of the battery connector to PCB issue. I'm no good with a soldering iron so I just took it apart and bent the connectors straighter so they put more pressure on the pcb. This worked for about 6 months, had to do it again last summer and its been fine since.
One issue I have is that the rubber band which covers the buttons round the outside of the device is now not sticking very well and I'm worried it'll get damp inside. What sort of glue should I use to re-apply the rubber band?
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The reason my first device was shutting down was, possibly, a known problem with shut downs when pressing menu when on the highway page. This can be related to the number of data fields you have selected to display on this page. One of the software updates is supposed to address this.
According to Garmin support, even if you have used the Garmin updater to install the latest software, it may not be installed correctly until you do a hard reset, even if the version number appears correct. I have done this with my current device and the problem seems to have gone away.
The highway page is not a lot of use anyway.
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Woohoo it works! Cautious optimism.
Didn't switch off once during the FNRttC, despite some fairly high speeds over fairly rough tarmac (and the foul weather).
A combination of the thicker padding + replace the screw with a cable tie, more foam inside the battery compartment, and using lithium AAs (which are light) seems to have produced some sort of fix.
I suspect that some sort of surgery to toughen up the contacts will be necessary at some point though.
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One issue I have is that the rubber band which covers the buttons round the outside of the device is now not sticking very well and I'm worried it'll get damp inside. What sort of glue should I use to re-apply the rubber band?
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I had the same problem with my eTrex Vista CX. I phoned Garmin in Southampton who identified it as a known problem. They invited me to send the CX back to them whereupon they would replace it with a similar unit.
Within a week I received a brand new eTrex Vista CX. (I think this model is now discontinued in favour of the hcx).
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Woohoo it works! Cautious optimism.
Didn't switch off once during the FNRttC, despite some fairly high speeds over fairly rough tarmac (and the foul weather).
Neither did mine, despite dropping it from shoulder height after the half-way stop :-[
Behaved itself very well.
I note that despite all the rubberiness and some attempt at a seal, the battery compartment is not waterproof at all.
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I have exactly the same problem with my Etrex. This is clearly a real issue with Garmins on bikes.
My fix was to change back to Duracells and also to strech upo the contacts so they pushed harder. Until then I was chucking teh baterries out because I thoiught they were duff!
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using about 3 rectangles of insulating tape along the outer face of the male part of the bracket (on the device). It does not rattle at all.
Nice trick, thanks for that. My Garmin eTrex Vista Hcx now sits very snugly in the mount.
I also had the problem with the unit turning itself off (it was an eTrex Vista) but mine turned itself off only once, and terminally. Garmin sent me a brand new Hcx within days.
I use rechargables now which sit snugly in the compartment. Fingers crossed this particular problem won't happen again.
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I have exactly the same problem with my Etrex. This is clearly a real issue with Garmins on bikes.
My fix was to change back to Duracells and also to strech upo the contacts so they pushed harder. Until then I was chucking teh baterries out because I thoiught they were duff!
If it is a problem with the contacts in the battery compartment itself, make small squares of suitable rubbery stuff and fit them in behind each contact. I think Garmin themselves did this at some point, early ones didn't have it but I see mine has bits behind the contacts. Maybe the rubber compresses after a while.
If it happens with mine and the problem is in the device itself as described above, it will be going back to Garmin. This is something they ought to have sorted out.
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Another method is to solder a capacitor across the terminals in the battery compartment, that way if the batteries are rattled and stop providing power the capacitor has enough charge to prevent it turning off.
Can't find the page with the best instructions but googling for "Garmin battery capacitor" gives some examples...
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To add to that, if the capacitor is soldered into the battery compartment it only helps if the issue is loose batteries (doesn't fix the PCB contact problem) - it needs to be soldered inside the unit for best effect. Even then, offroad it isn't 100% - the full-spectrum approach works for me though (stretch battery clips,fit capacitor, use external batteries).
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FWIW I haven't had a single unwanted power-off since I've used a zip-tie to lash it more securely.
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That's interesting. Prior to the weekend I had the HCx mounted on an Acor bar extender tightly mounted to the bar. The bracket was an oversize one padded out to fit on the normal size Acor. So a little bit of give, but not much. Never switched itself off due to road shock despite some hard hits.
Prior to Saturday's Swindon ride I thought I'd fix somthing that wasn't broke, and refitted the Acor with a couple of strips of rubber at the bar clamp. So there was a bit of give there and some movement when going over bumps, which I hoped would have a shock absorbing effect.
Not so. For the first time, on Saturday, it switched itself off 3 times, twice over cattle grids at a fair speed. Over bumpy sections the device appearred to be vibrating quite a lot.
It seems it is better, unless you have some way of damping the vibration, that a more solid mounting is better, which ties in with your experience.
I shall update in due course.
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I have a Vista HCX and have never had this problem. I have come across another issue to do with Lithium batteries. I have been using them because they give much longer run time than the duracels I was using. However, I have discovered that, when the low battery warning comes on on the Garmin, you have about 10 seconds before the unit shuts down. With duracels this can be several hours. This must be a feature of the lithiums. I guess that they have a very flat power curve that frops like a stone at the end. Bit of a bummer when you are half way up the Cabrach and don't want to stop for fear of not getting started again.
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Is the battery type set correctly?
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Errr... No! It is still set to Alkaline. I read somewhere that this was a good idea as it made the batteries last even longer. I will check out the instructions.
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If you're using Energizer Lithiums then 'alkaline' is the best setting, IMO.
I have seen them give up to 50 hours (in a Legend Cx) but it is true that you don't get much time after the 'low' warning - 5-10 minutes at most. Carry a spare pair - they don't weigh much after all.
Regarding the vibration problem - it does seem unclear whether the best fix is a more compliant mounting (oversize mount with layers of rubber), or a more rigid mounting (eg http://www.gpsw.co.uk/details/prod2394.html (http://www.gpsw.co.uk/details/prod2394.html) ) - both have been tried with some success. I prefer a compliant mount but I think eliminating the 'rattle' using layers of PVC tape as described earlier, has helped a lot too.
Just completed a week of touring on very rough roads where three of us all using the simple anti-rattle PVC tape didn't have a single power-down between us.
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FWIW, my Legend Cx was doing this off periodically ever since PBP. The other week it suddenly got really bad. Now sorted by replacing the clip on the back plate which had a hairline fracture, and putting duct tape on the handlebar bracket.
Lithium batteries last for ages PROVIDED you don't inadvertently leave the backlight on all day. If you tend to do that, I recommend a cheaper option!
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Regarding the vibration problem - it does seem unclear whether the best fix is a more compliant mounting (oversize mount with layers of rubber), or a more rigid mounting
The only time I had this problem was when I tried a more compliant mount. If the shock-absorbing motion cannot be effectively damped then it is better to have a firmer mount. IME.
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Regarding the vibration problem - it does seem unclear whether the best fix is a more compliant mounting (oversize mount with layers of rubber), or a more rigid mounting
The only time I had this problem was when I tried a more compliant mount. If the shock-absorbing motion cannot be effectively damped then it is better to have a firmer mount. IME.
Using the Vista on my MTB and Moulton, both of which have some sort full suspension causes the unit no problems at all. It's only on my Roubaix that it happens. IME, a more compliant mount and lighter batteries has significantly reduced the problem on the Spesh (cattle grids are still an Achilles heel, as Pluck knows >:().
It definitely seems to be particular combinations of amplitude and frequency that cause the problem.