On board batteries...

[Biosearch]

Okay, so not having schematics (or even really knowing how to read them properly if I did) I have a question... After taking apart one of the used m100s I got for cheap off of eBay in order to replace a bad screen I noticed that there appeared to be something on the circuit board that resembled a battery. You can see it in the in the eighth image down on

http://www.pspilot.de/pppm100/pppm100.html

Image: m100_07h.jpg

Curious, is that an actual batter, would it need to be replaced in an older palm, if it isn't what the heck is it and is everyone having a good holiday season?

rob

[NetBrakr]

My guess that thing isnt a battery. I had a m105. Its not saving the date/time, once you taken out the AAA batteries, so I dont know what that is. Probably its another circuitry.

JC

[Rob M.]

My guess that thing isnt a battery. I had a m105. Its not saving the date/time, once you taken out the AAA batteries, so I dont know what that is. Probably its another circuitry.

I believe that what looks like a very small button cell in the lower left corner of the photo at <http://www.pspilot.de/pppm100/m100_07h.jpg> is what's been referred to elsewhere as a "super-cap", i.e., a large-value capacitor. It's function was supposedly to store a charge that would maintain the voltage on the CMOS chip for long enough to let you change batteries without losing the data on the Palm.

Unfortunately, like most large-value electrolytic capacitors, they're lossy. And get worse as they age. After a year or three, the super-caps used in the M100 series wouldn't retain enough of a charge to preserve whatever data was in memory, resulting in the need to to a complete restore after every battery change.

My wife and I both had M105s. Both were eventually afflicted with that problem. I resolved it by soldering pigtails onto the battery contacts that let me clip on an external battery pack while I changed the AAA cells.

[SGosnell]

I still have an M105. I changed the cap once, but the new one died too. I only use mine for geocaching, where I need something cheap in case I break or lose it, so resyncing everything when I change batteries, which doesn't happen that often, isn't a big deal. I made up a rig using an automobile fuse, connected to a universal wall wart, that kept voltage while I changed batteries, and charged the rechargeable batteries I used, but I haven't used that in a long time. I just live with losing everything when I change the batteries.

[zire102001]

i have a palm IIIxe and an m105 with the battery problem, however the IIIxe's capacitor has lasted more than three years, i found out mine was manufactured right before they shipped/debuted February 14 2000.

[vincent_vango]

I think that is cell to let the clock run when replace battery.
Because it will aging also, so need to replace if it is not working if you don't like to reset the date & clock each time you replace the battery.
Because I have a Nokia 6510 mobile phone, there is a small cell like a screw size on the printed circuit board, now it's aging already, when I try to replace the SIM Card, all the data on the moblie will gotten, need to reset again. =.=!

[raspabalsa]

Hello vincent_vango

Actually, it's a capacitor used to preserve the user's data while changing the batteries (as mentioned a few posts back). And of course it also preserves date and time. This is needed because the palm models discussed here use RAM as storage medium. Most phones use Flash ROM as storage, thus they don't need to keep the memory powered to preserve data. When the capacitor in these palms fails, all data is lost when batteries are changed.

[vincent_vango]

Hello raspabalsa.

Thanks for your infromation ^^!