Thinkpads Forum

I need one and I've seen some other people on the 'net that need one too. I looked it up a while back and couldn't find it, read some forums, and gave up.

I went back to my grandpa's house the other week to fix up a computer for my cousins, and I saw it in his printer box thingy.
I can't find the forum, but I remember something about soldering a cmos battery wires to a regular thinkpad one or something?
If not then where can we buy one, I looked it up and searched for a good few hours, still couldn't find one.


I know how to bypass the problems this creates when booting up:
Boot into bios.
The "save and exit" will be unavailable because there are no changes to save, unlike the similar problem I had with an Aptiva.
Change a setting, and then change it back to its previous setting, the "save and exit" option will be available now.
Click "save and exit" and you will notice the system does not reboot, but continues booting.
*You have to do this every time you boot the machine, including reboots and hibernation.

This has fixed my black screen of death and failures to boot into windows 95. I have proven that this works every time it boots up except for when it decides there's bad memory or the keyboard and mouse stop working(probably because of bad cmos battery too)

That is a temporary fix, but if anyone knows where to buy or how to outfit a battery for one of these please let me know, I'm sure a ton of people want to know too

it has been suggested to de-solder and remove the existing battery on the board, noing the +ve and -ve terminals and sldering on a cmos battery from a THINKPAD 600 or similar, by removing the connector and soldering the wires to the board. I have to say that this did absolutely nothing for me and it was a bit of a pain knowing that it wasn't exactly ALL ORIGINAL. iIn the end i looked for a motherboard on EBAY and found a NEW OLD STOCK MOTHERBOARD with a good battery (still good now too after more than a year) You can still find these boards on EBAY if you are interested. Much better than soldering.

mnowell69 wrote:it has been suggested to de-solder and remove the existing battery on the board, noing the +ve and -ve terminals and sldering on a cmos battery from a THINKPAD 600 or similar, by removing the connector and soldering the wires to the board. I have to say that this did absolutely nothing for me and it was a bit of a pain knowing that it wasn't exactly ALL ORIGINAL. iIn the end i looked for a motherboard on EBAY and found a NEW OLD STOCK MOTHERBOARD with a good battery (still good now too after more than a year) You can still find these boards on EBAY if you are interested. Much better than soldering.

Paying for a whole new board seems a little expensive. Is it possible that the battery from a 600 does not have the correct votage/amperage for the 701?

Scroll down to # 9 and have a look at the picture.

http://thinkpad-forum.de/threads/129610 ... kpad-701CS

hjanzen wrote:Scroll down to # 9 and have a look at the picture.

http://thinkpad-forum.de/threads/129610 ... kpad-701CS

Yes, you resolder another battery there. Question is, which one?

That photo shows that whoever did that modification used a standard IBM CMOS battery for the 600 series systems (FRU 02K6486). The battery used in those is a regular CR2025 lithium coin battery, as can be seen on the label.

In reality, any 3V lithium coin battery will work; the only real difference is in the current capacity between each of them. If you stick with the CR20xx series, then you have a choice between CR2016, CR2025 or CR2032. All of them are exactly the same size in diameter (20mm; or the first two digits of the battery number). What is different is the height (thickness) and that directly relates to the current capacity; thicker = more current. The last two numbers of the batteries are the height in 1/10mm. So the CR2025 is 2.5mm thick and generally has a capacity of 165mAh, whereas the CR2032 is 3.2mm thick and is usually rated around 225mAh. All things being equal, the higher capacity CR2032 should last longer than the CR2025. I don't have a 701C so I can't say for sure that a CR2032 would fit inside that area.

In any event, you should use a CMOS battery that was designed for a Thinkpad as it will already have leads attached to the battery. The CR2032 battery was used in CMOS batteries for the T2x series (among others) so they should be easy to find. Simply cut the connector off the battery; clip only one lead at a time to prevent an accidental short! Solder the red and black leads according to that photo. I'm assuming that whoever did that mod knew the correct polarity .

This one will do perfectly:

http://www.ebay.nl/itm/IBM-ThinkPad-CMO ... 19af30ac67

http://www.ebay.com/itm/5-BR1225-1VC-PA ... 0704359395?

I purchased these for my 701's.

There are many references on these boards to replacing the cmos battery in a 701C.

Unfortunately this doesn't help someone as impractical as I!!!!!!.

Does anyone have some instructions for how to go about this task?

Thanks in advance for any and all advice.