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My 276C started losing its time after a few hours turned off. The problem was a 3.0 volt internal battery soldered to the PCB that powers the clock chip. Mine was down to 0.76 volts and is a couple years old now.

I didn't do an exact replacment, just picked up the smallest 3.0 volt battery I could find at rat-shack, soldered on wires, and soldered to the PCB pads. A fairly easy job, except the lcd display has a flat cable with tiny traces and it's a little hard to get it back in the socket.

Garmin wanted $200 flat charge to repair. There's going to be lots of these failing as the product ages, hopefully this post will help someone out.

Wayne

Ok first remove the screws from the box shell
and the ring of the antenna base connector








carefully lift the aluminium paper behind the LCD screen (dont worry it has only soft glue)




remove PCB screws






at the back of the PCB you can see the battery








It's a VARTA MC621






Replace and voyla... no more acquiring satellites delay

Nice, but you just responded to a thread that was over 8 months old.

"Nice, but you just responded to a thread that was over 8 months old."

At least his post was relevant, and useful to somebody who has to perform the battery replacement. There will be tens or hundreds of thousands of them failing. I'm surprised nobody's responded before now.

tsizmo,
Thanks for the detailed how-to. It won't be long before I'll be needing a new battery too.

After closing the unit, will it still be waterproof (IPX7)?

Yes! I have test it.
Just be sure to carefully wipe the rubber seal around the unit
with a soft slightly wet cloth before you close the unit

I recently found that VARTA MC621 is hard to find
So I found a good replacment for it :

it's a SANYO 3v Li Rechargable you can order it from here: http://parts.digikey.com/1/parts/1638-b ... 1-tz1.html

Thanks for this topic. Garmin tech support couldn't even tell me if anything was wrong with my unit, but told me that I can send it for repair for $200. It's currently loosing date/time in about 4 days and then I have to use "stored without batteries" "feature" I have battery on back order from DigiKey. Couldn't find anyone who has it in stock.

However here's interesting thought. My GPS is always stored with fully charged main battery. And it is loosing time anyway. This makes me think that this little clock battery is being charged only when connected to external power. During the summer I use it on the boat, connected to the boat battery for at least 10 hours a week. And I never have this problem. During the winter, however, I only use it occasionally in the car and often don't even bother plugging it in, but charge it once in a while, that takes only an hour or 2.

So may be you just need to keep it connected to external power for a day to let the clock battery charge? While waiting for replacement, I did just that. Kept it on AC adapter for a day and put it on the shelf. Will let you know what will happen in a week.

I had GPS-12 before for many years and never had this problem. Time could be off by a couple of minutes, but never WAY off, like I have now.

As I promised I am going to post my findings. After I kept my unit connected to the external power supply for a day, the problem with date/time went away. It's almost 2 weeks on the shelf and it's still showing the correct time. Used to be 3-4 days max.

Guess the reason is that clock battery is charged only when external power is used and main battery does not supply power to the clock chip or charge clock battery. So, perhaps, you don't need to replace this battery in most cases. All you have to do is to keep your unit on external power for several hours to get the clock battery charged.

According to the battery specifications, it should handle at least 1000 cycles, before the capacity starts to drop. And even then it should still be usable.

It seems everyone has the same problem with the 296. Like others, I always kept the battery pack fully charged but the unit kept losing the date (hence a long time to reinitialise each time). I called Garmin about this and actually got a response: they told me that the internal clock battery is recharged only when the unit is plugged in to external power AND TURNED ON. So now I regularly plug the unit in and turn it on, even though the battery was already fully charged, to keep that clock battery going. I think it was not a good design. Anyway, that was the information I got from Garmin.

In my case Garmin gave me misleading info ending up with suggestion that I send the unit for $200 repair. After I discovered that unit has to be connected to external power source for clock battery to be charged, I send them complain and they responded with apology and confirmed that unit MUST be connected to external power in order for the clock battery to charge. It takes much less time for the main battery to charge, then for the clock battery. So if you keep it connected long enough only to charge main battery, clock battery will go dead. And in my case (276C) I don't have to keep receiver turned on. Just keep it plugged in.

I used this "old" post to replace the backup battery in my Garmin 496.
This was the 3rd unit with such a problem!
The old battery gave a 0.6 V, which is clearly insufficient.
I was only wondering why the date and time kept on going when I took the main battery out and replaced the backup battery.
When I started up the unit the date and time were kept!

Hans

They also may have a a capacitor - just a guess. It doesn't take much power to keep CMOS clock chip running.

I guess all the handymen are going to discover this post eventually, or put up with the ridiculous start-up times, which are a real pain when travelling. tsizmo has gone inside and showed us it can be done. So have I and improved on the procedure plus discovered a couple of traps.

Firstly, for those that don't know the above missing pics are here http://s280.photobucket.com/albums/kk192/jimmisjimmis/. However they are still nominated as non-permanent so I have added them to this post plus a couple of others showing the battery innards I forget where I found them. Aha, have to do this 3 pics at a time, so here's 3.

To add to the knowledge, firstly, I note there is a fair bit of room to fit a replacement battery in the vertical direction, so I fitted a Panasonic VL1220-1VCE being 7mA instead of the 5mA used above. It is 12mm dia and can be stood up as there is a good sized cavity above it - I am hoping this buys me a couple more years before the battery dies again.

The second thing of note is that the connector from the screen to the board is a bit special, and hard to reassemble - so try not to pull it out! If you do I finally figured there is a flap which needs to be in the vertical position, the cable is slid in horizontally and the flap pushed down to lock the cable in place, it is a cam locking thing, but only about 1mm long so hard to see, easy to do when you get it. A USB key (plug end) was just the right size to push the flap securely home.

The cable from the charger plug input to thetop of the PC board is a real cow to get back in, it goes in easy enough but it is very short and hard to grip and push square. Study it before you pull it out, and you have to pull it as the aerial connector won't come free of the board otherwise. I found having the board nearly home I could get at the cable with a THIN pair of long nosed pliars and push it in, then screw the board together (noting you need to push it in very squarely to engage the pin set on the case).

next 3

3 more

Thanks for inserting the photo's again.
Remark: The order is now changed, numbers give right sequence.

This was my "original" problem. I was getting the "Missing battery" message as a result of not powering up the GPS for several months. And I discovered why these ridiculous reset times were happening and fixed that - but at this moment the battery power issue remains. Apparently giving it a "bit of a hit" will get it over the threshold so the (obviously deficient) Garmin internal charging circuit "sees" the battery and will kindly charge it. However right now I don't have this sorted.

A few minutes on a 6V torch battery wasn't enough. Whilst tempting, I am reluctant to hit it with 12V on account of the electronics in the box. And I can't find my multimeter, so stuff it I will buy a new one tomorrow and continue. However, buying another battery is obviously an option! But I will dismantle the item and give the batteries a bit of straight on the nose shock treatment before giving up on the idea of a restitution.

Stay tuned for that one. Possibly it belongs in another thread, if someone know which one a cross link would be handy. Both of these issues belong to a much wider range of models than just the ones discussed here, that much is obvious from a bit of serious Googling on the topic. However this thread is the only one with pictures.

last battery pic I found.

This info came from http://forums.gps.org.nz/viewtopic.php?f=7&t=4131

And now that I've re-read it I see it is essential to pull the case apart to revive the battery, missed that on the earlier reading!

back to internal batteries, details of the VL1220-1VCE are here:

http://au.farnell.com/panasonic/vl1220- ... L1220-1VCE

Can't post .pdf's so spec attached to post. Can't remember where I found it now. But I have fitted the battery and the GPS works again, so that is a good step forwards!

Note for the original and new batteries the side with the writing on is +ve. It also has a longer leg. On the new one the orientation is backwards as the tab legs come off the +ve and -ve sides opposite hand - no problem just get it right!

Note the p/n VL1220-1VCE VL is Vanadium Lithium, 12 is 12mm dia, 20 is 2.0mm high, 1VCE gets leg tabs how we want them.

These pics show the installed position, tilted slightly to make sure it misses the case. Note the soldering iron - the smallest one I have but really it is a bit big for the job. Get one leg soldered on quickly, check then do the other one. Batteries are not good with heat, it really is important to be quick - and good! or get the right gear - and be quick (and good) anyway!

Of course a perfectly sensible alternative would be to solder a red and black wire where the battery goes and silicon the thing somewhere it can be easily got to for replacement - next time for me maybe, if there is one for this unit, with the bigger battery I am hoping some 10 or more years down the track.

Just for completeness I didn't initially get that photos 01 and 02 were telling me to pull the nut off the aerial connector as the first job. Thankfully I worked this out after unscrewing the board and before applying too much force to it! But I think this is when I accidentally pulled out the screen cable! Forewarned and careful it is not too hard, as long as you have at least a fair degree of confidence in this sort of procedure - or the preparadness to shell out for a newer model!

The complete data sheet is here: http://datasheet.octopart.com/VL1220-1V ... -17980.pdf

Which reminds me, has anybody stumbled across a way to get POI's (Points Of Interest) into the 276C? Garmin a couple of years ago told me it wasn't going to happen by way of software upgrade. If anyone reading this knows of a way please start a new thread and put a link in from this one. Not counting setting a whole pile of waypoints manually, that is. I like the idea of putting in the speed camera database but can't see a practical way. I suspect there is a hardware limitation here. Thanks.............

OK, the main battery was a snack. The pics above are correct. What they don't show is that the whole battery pack is encased in another layer of sheet plastic - which you need to carefully cut down the middle with a small pair of scissors. The outside of the plastic sheath has double sided tape top and bottom which holds it in the case firmly.

BEFORE YOU START make it really obvious which way round the battery pack goes, the stupid thing is symettrical and I was matching up penknife gouge holes where I had run a pocketknife round the edge to free the thin back cover with the output connectors on. Once you have a side free (this is easy) just prise it off against the double sided tape and it separates easily.

When I opened it both batteries were equal at 0.35V - they should be 3.7V each. I put a 6V lantern battery across the terminals of each battery (connect +ve to +ve, -ve to -ve) one at a time and in about 30 seconds each they were over 2V (with the lantern battery disconnected). I figured that should be enough for them to be seen by the electronics, reassembled the thing and clipped it back in the unit where it is charging merrily away. From picking up the battery to getting it to be charging was barely 5 minutes, unlike the job above which was about an hour of stuffing around with it, about the same to write it up and some 4 hours of research in front and along the way!

So fixing the "Battery Missing" problem is easy and quick. Of course the problem has only occurred because the battery is on the way out so it will need replacing eventually. Assuming it charges up OK I will seal the back panel with silicon and then do a few full cycle charge and discharge loops. As long as it is runing for several hours each time that will be fine for me. Typically I would get around 10 hours from a full charge, screen brightness 2 back from full. I hope other people can use the above info, save a quid and enjoy some of that feel good factor from getting a win (for a change!).

For the record i bought this unit in May 2005. My internal battery was under 0.25V and falling for every second it was connected to a multimeter, what an appallingly bad design huh! However lots of stuff about the 276C is really smic and the screen resolution is just brilliant (then again I still remember that the price smarted a fair bit but oh the freedom it gave to a certain Ducati ST4S wandering the backroads of this fair land down under).

If I don't post again that means everything above was a beauty, otherwise I will log any issues that resulted. This of course is because I appreciate that somebody else here did - which I found very helpful, and so the good karma goes on............

Well it all works a beauty. At least 8 hours service life from what were apparently totally shagged batteries. This is the main external battery I am talking about, not exactly the nominated thread topic! Even though the "external" battery is really internal. Oh heck if a moderator has a problem please feel free to try your darndest to separate out these topics!

To help others diagnose if they are likely to get their main battery back to life - when I first realised I had a problem a while back I measured the volts, didn't know which terminal was what but loosely remember measuring about 1.5V. So, now that I know what is going on, I measured the volts again.

I left the unit on last night to self discharge and this morning it had 7.19V across +'ve to -ve and 4.82V across +ve to data (also a -ve). I then turned it on to self discharge 3 more times just to see how low it could go. After that we were at 7.04V and 4.68V for -ve and data respectively.

So, somewhere between 7V and and 1.5V the charging circuit refuses to latch in. Which is pretty poor as a time discharged battery is not necessarily cactus, mine certainly seems to have revived to the point that I will still get a useful service life from it. I didn't check the voltage after I gave the batteries the heart starter treatment but I would guess it was around the 6V mark. Interestingly when connected to the power after repair the display showed a full battery but charged it for ages anyway before declaring that it was full. Now that I have self discharged it the display shows the correct empty battery picture and is showing it progressively being topped up, as it should.

I have the latest firmware on this unit (5.4) and I also note with wry amusement that it was to improve the battery life designation. When I was doing the triple discharge I had remaining life showing of 1.6 hours initially, 42 mins on the second one and I didn't look for the others, but the whole triple discharge thing didn't take more than an hour, and some of that was slack time when I didn't notice it was off - so this may still need a little work, or it may simply be that my battery is operating outside of normal parameters given that I have (unwittingly) abused it quite severely.

See the below thread for help with that oh-so-important first step - getting the bloody thing open!
viewtopic.php?f=4&t=7664

And, just a tip from me for your patience in reading this far, the display on the 276C can be set up to be much more user friendly than what you get out of the box. I don't remember exactly where the menu items are, but I have full screen map showing with speed and altitude at the top and distance to next and destination at the bottom. When tooling around country roads on the bike this is all you are interested in and not wasting screen space on the side menu and getting mapping instead is really useful. And I find in the car it is also just brilliant, plus I get the audio for extra (usually banal) info to help with navigating. Enjoy............