701C battery rebuild: still says "not installed"

[keenmaster486]

I got a Thinkpad 701C on eBay. It was listed as missing the battery, so I found a NOS "Xtend" battery for the 701C on eBay as well.

When I got the battery it was still in the original packaging and had not been opened. As expected there was a little corrosion, but no leakage. The corrosion had gotten to the PCB, so after I had removed everything for rebuilding, I resoldered everything on the PCB to the specification in this article: http://www.conradshome.com/thinkpad/701/battery/

The pins on the Dallas ID chip go to the pads they're supposed to go to. I've checked for continuity using a multimeter. There are no shorts anywhere.

After replacing all the cells with standard AA NiMH rechargeables, the pack reads 11.7 volts on the multimeter. The laptop powers up and boots using only the battery.

However, the system still cannot detect the battery. It says "not installed" no matter what I do.

Yes, all the pads are scraped shiny.

What gives? Has anyone had this issue before? Do I have a shot ID chip?

[Thinkpad4by3]

Will the machine boot at all from the NiMH batteries.

[keenmaster486]

Will the machine boot at all from the NiMH batteries.

Yes, if you install the battery and unplug the AC adapter, the machine will turn on and boot all the way, and function normally, except that it still claims the battery is "not installed".

[keenmaster486]

Could this potentially be a problem with the Dallas ID chip on the battery? Perhaps I fried it when soldering? I don't know how much heat it's designed to handle.

[Ghostdog]

Hello, have you found any solution ?

[MadcatSE]

Hello. I have successfully rebuilt the battery using the same guide. The laptop recognized the battery, it even charged it. Unfortunately the next day one of the pins that connect the battery to the motherboard had broken off due to corrosion and shorted the DS2434, killing it. After that the laptop continued to work from the battery (until there was charge in it), but was indicating that there was no battery or it was damaged. The only thing that helped was ordering another (new*) battery and trying to charge it. It worked! 30 seconds of autonomy!

So now I want to future-proof this thing. The DS2434 could be read and written by Reveprog-IS programmer. I ordered one and will make a dump of ROM/RAM with it. New DS2434 are being sold at aliexpress so I could make myself a "new" battery by installing a fresh DS2434 instead of a dead one. I will gladly share the RAM/ROM here when I'm done. Maybe I even will sell them pre-programmed if there is interest, but the Revelprog-IS is too expensive for the buyer (it is).

[fatkatsupra1]

mad props

post pics!

[MadcatSE]

mad props

post pics!

Here you go. These were taken right before the disaster struck.

And here is the video of the machine right now:
https://youtu.be/AHX7RdPyV5M

The programmer is still on it's way, so I haven't opened the second battery yet.

[RealBlackStuff]

Why not try a dirt-cheap CH341A instead of that expensive Revelprog-IS?
Such as this: https://www.ebay.ie/itm/255182257268
Plenty free software for that as well!

[MadcatSE]

Well I didn't find any complete and confirmed solution to reading/writing DS2434 specifically. I do have 866 programmer, but it doesn't support 1-wire. I found some programmers that work with 1-wire, but they use 2 pins (power/data and ground), while DS2434 has three. And there are schematics of how to read/write it using COM-port and a MAXIM-designed adapter, which is also quite rare and not that cheap. Only revelprog seemed to provide a straight and easy solution, so while yes - it's REALLY expensive, but I want to be done with this battery this year . I might sell it afterwards to try and recoup some of the money. Oh, and I really don`t want to screw this battery either.

[Ghostdog]

I've found that it is not so easy. The chips from AliExpress have different manufacture ID, which is programmed at the factory and cannot be changed by the programmer. So it is not possible to make identical copy of IBM chip. As I see there is only solution is to also modify laptop firmware or charging controller firmware. Maybe someone have such experience ?

[MadcatSE]

darn, you're right! Datasheet says that ID is unique for each customer, not the IC itself. darn, that means that I can only reset the counter and not much else. So I guess the BIOS needs to be disassembled and the ID check must be turned off. And that could be really tricky.

[Ghostdog]

darn, you're right! Datasheet says that ID is unique for each customer, not the IC itself. darn, that means that I can only reset the counter and not much else. So I guess the BIOS needs to be disassembled and the ID check must be turned off. And that could be really tricky.

Hello, have you managed to make a dump of ID chip ?

[marinelayer]

Hi - also currious to know if anyone has made a dump of the original good DS2434.

I've got one that I pulled from a leaking battery with the correct manufacturer identifier: CA BD - but I think it may be damaed because when I swapped the cells the laptop is still telling me it's a "Bad Battery" and will refuse to charge it even though it runs.

[marinelayer]

For anyone reading this thread, I was able to make a clone of the Dallas ID chip and open-sourced it. I did a full rebuild (3D printed case, terminal board and even label included).

The code can be found here: https://github.com/hrushka/701c.org/tre ... src/ds2434

The finished product can be found here: https://www.701c.org/projects/battery

[Franchute13]

Very nice work MarineLayer!!

[moore101]

I can vouch for the 701c.org butterfly project. Purchased two of the battery circuit boards, one bare and one with the new ID chip. Unfortunately my stock ID chip was dead and the system wouldn't charge the battery, though my rebuilt battery did work. Switched to the board with the new chip and it works great. System sees the battery and after a few charge discharge cycles it's working very well.