Palm m105 battery change lost data

[Sy Russell]

I've had a Palm m105 since Sept '02. Today after changing the alkaline batteries, the screen showed the palm logo and asked “Erase all data? Yes? Press up button. No? Press any other button”

I pressed the down button, but the logo, then the “Erase” question reappeared. One by one I pressed all the different buttons (EXCEPT of course, the “up” button. I pressed RESET and repeated this process a number of times, with the same unsuccessful results.. Even when I thought the handheld was OFF, the logo now appeared to be fluttering.

I then took out one battery to dbl check that it was in the correct position. Nothing wrong there.

When I pressed the ON button again, the logo was steady, the screen put me through the set up with tapping with the stylus and setting the date (the time was correct).

Pressed DONE when I was finished. I pressed the DATEBOOK button and found that previously entered data was lost in all applications.

I hope someone can tell me how to regain the data. (I hotsynced a week ago, but want to regain other data). Also would appreciate your thoughts on what went wrong. I’ve changed the battery before and never had the logo fluttering nor was asked whether or not I wanted to “Erase”?
Thank You.

[Jim Cooke]

Sy,

Bad news, I'm afraid. :( The 105 uses a small capacitor that holds a charge for about five minutes when your replace batteries. These capacitors dry out over time and lose the ability to hold power when you change batteries. It usually happens just the way it happened to you. You may have taken just slightly longer to change betteries and than usual and, since the capacitor might be holding 5 or 10 seconds worth of charge, you got a hard reset.

Any data that you didn't have backed up through a hotsync is gone with no way to recover it. When you hotysnc, everything that was backed up will be restored but your week's worth of data is gone. I can't emphasize enough how important it is to do a daily hotsync on Palm units without an expansion card because your data loss is permanaent as soon as you have a hard reset.

You now have two choices. The first is to always do a hotsync before you change batteries and then do a restore hotsync after the battery chance. The second is to get either another used M105 or move up to a newer Palm. The capacitor can be repaired but, unless you have experience doing surface mount electronic repairs, it's not a DIY job. The value of the M015 is so low that it doesn't makes economic sense to have it repaired professionaly.

[Sy Russell]

Jim, your explanation addressing the fluttering logo and "Erase" question is much appreciated for its thoroughness. I thought I might have inadvertently done a hardset by holding down "Reset" too long. Tku, Sy

[Peterthinks]

Well I'm a handy kinda guy.
Where is this Cap and what are it's specs?
I can probably change it.

I have about 3 dead memory palms.
I take the battery out and poof! everything goes away

I made a jumper battery out of an alluminum can there are pictures here

http://members15.clubphoto.com/peter627123/2692816/guest.phtml

so if your Palm loses all it's memory when you change the batteries give it a try.

[Peterthinks]

I just want to make it clear that this is not reccomended by Palm and you try this at your own risk.The worst thing that happens to me is I get the hard reset I would have gotten anyway but there is a chance you could screw up your Palm trying this.

[dougm]

As an otherwise satisfied owner of a few M100/M105s, I was suprprised when they started losing data during a batter change. I read about some ideas online, including a capacitor replacement. Replacing the cap. seems like a lot to do, and I don't have the skill or good enough soldering tools (nor do I want to pay someone $$$ to fix a $ PDA !).

Palm Support's bogus idea of replacing one battery at a time got me thinking. The 1.5V batteries are in series, creating a 3V supply. Obviously, removing one battery will open the battery circuit = no current, memory lost. But what if the battery circuit was kept closed with a wire, while replacing one battery at a time. I tried that and it worked!

Do this at your own risk!

You need one jumper wire with mini-clips, like Radio Shack 278-016 ($7/pr) or 278-017 (discontinued). The alligator type clips are too big. Or just use a paper clip (not as convenient) -- or two pieces of paper clip and alligator clip wire.

o Turn off Palm.
o Open the battery compartment (duh).
o The contacts on the left side (as you look at the back) are really just a single piece of metal. Attach one end of the clip wire there and leave it there throughout the operation. There is room for clip attachment in the center of that contact.
o Attach other end of clip wire to the top-right battery contact (+). The top of this contact has room.
o Carefully remove top battery and replace it. Use the stylus to remove the batteries to avoid knocking the clips off with you fingers.
o Move clip from + to the lower-right contact (-). Clip at the lower end of the contact.
o Remove lower battery and replace.
o Remove both wire clips.

That's it. The Palm should behave as if nothing happened.

Notes:
o I'm not sure what happens inside the Palm during the operation. It could be the Palm relies on the resistance of 2 batteries in series. So I wouldn't leave the clip wire connected any longer than necessary.
o Using a paper clip will work, but it's too thick to get into battery contacts. And one slip and you've lost your data.

[potter]

Originally posted by dougm
Palm Support's bogus idea of replacing one battery at a time got me thinking. The 1.5V batteries are in series, creating a 3V supply. Obviously, removing one battery will open the battery circuit = no current, memory lost.
Palm Support's idea is not quite bogus. If the capacitor is still operational but just does not working up to full capacity, then the idea of switching one battery at a time is a timing issue. One can change one battery faster than one can change both. Thus the time without current is less. However, if the capacitor is not working at all, it does not matter; open the circuit and the memory is gone.

Notes:
o I'm not sure what happens inside the Palm during the operation. It could be the Palm relies on the resistance of 2 batteries in series. So I wouldn't leave the clip wire connected any longer than necessary.
Several people have successfully used NiCd and NiMH batteries in their palm devices. NiCd and NiMH batteries have a considerably smaller internal resistance and Alkaline batteries, therefore I would not worry about Palm response to the one battery case. However, the batteries response we need to take note.

First a little math: A normally 1.5 volt, is near death and so has, let us say, about 1.0 volts. We are shorting this battery out. Let's see, V = I * R, Volts equals Current times resistance. If V is 1.0 volts and the wire short the battery out has a resistance of 0 ohms, that means the current is, ah ...

Actually, the wire has a very small, but non-zero resistance and the battery itself also has some resistance. Alkaline batteries have a comparatively high internal resistance, so unless one is using a very small gage wire, the worst thing that is going to happen is the wire and/or the battery might get a little warm.

However, if you are using NiCd or NiMH batteries; they have a very small internal resistance. If one shorts out a fully changed battery, it is easy for them to dump all of their energy all at once. This can results in burns, fires and even small explosions. Therefore, instead of shorting out the battery with a straight wire, I would suggest throw in a small resister also. Assuming worst-case scenario of shorting out two fully charged batteries at about 3.2 volts, and not want a power discharge greater than a quarter watt, my quick math says we a resistor no smaller than 41 ohms. I do not remember what the next common resistor size above 41 is; I think it is 47-ohm.

Someone will have to experiment to see if shorting out one near dead battery with a 47-ohm resistor is enough to keep the memory alive.

[dougm]

Those are excellent points, esp. about the shorted battery. In my excitement, I forgot that the wire not only creates a new path for the PDA's internal current (good), but also for the near-dead battery to short itself (bad).

This duration of this battery short starts when the clip is attached and ends when the battery is removed -- then begins again when the new battery is inserted (with greater voltage and thus more current). So speed of the operation is important.

I agree that a resistor would be a good idea, but that's more assembly bother, and I wanted to keep it as simple as buying one thing at Radio Shlock.

One thing I'm not sure of: is an alkaline battery (or the other types you mentioned) an Ohmic type of load that obeys V=IR regardless of current value? Also, a rapidly heating wire probably develops a pretty good number of ohms (until it melts and opens the circuit .:rolleyes: ).

[JohnKes]

Originally posted by potter
However, if you are using NiCd or NiMH batteries; they have a very small internal resistance. If one shorts out a fully changed battery, it is easy for them to dump all of their energy all at once. This can results in burns, fires and even small explosions.

Yes, my dad caught our carpet on fire when he shorted out a NiCd pack, many years ago.

[dougm]

Okay, I've got a new way to do this. :rolleyes:

Forget what I said before, about using clip wires to short the battery posts.

New way:

1. Get a 2032 coin cell. This is a 3V battery, and is prob. the cheapest coin cell you can buy. About $1.30 at Home Despot. They're commonly used as CMOS batteries in computers.

2. Get a small binder-clip, made for clamping a small stack of papers together.

3. Wrap electrical tape around the clamping surfaces.

4. Cut 2 lengths of #24 wire, black and red, about 4". Strip each end about 1/2". Bend one end of each wire in a hook shape.

5. You can guess the rest. Clamp the wires to the coin cell, red to +.

6. Put the Palm face down on the edge of a table, so the batteries are to the left. Attach the hook ends of the wires into the outer sides of the near battery terminals.

7. With your right hand, hold the PDA and apply a slight force on the wires so they stay hooked.

8. Replace the batteries -- one at a time :) -- with your left hand.

9. Release the wires.

Notes:

This method applies the proper 3V to the PDA at all times during the change.

When storing the coin cell thingy, keep the bare wires apart so the coin cell doesn't short. (Duh)

Before beginning the operation, roll the old batteries in place with your fingers. This releases some friction at the ends of the batteries, making them easier to remove.

Be sure you attach the wires to the correct side. The other side is a dead short, so you will just short out the coin cell (and lose your data).