I am running an old Crutchfield 486 tower. It has Windows 3.10 and DOS6.0 Enhanced. My problem is that the Twin Head real time clock chip is dead (It is the same as the more common Dallas RTC chip) The one for this computer is model TH1287. I found another old 486 computer in my storage. It also has a Twin Head RTC but the model is TH6887A. According to resource800.com the difference between the TH1287 and TH6887A is that the "A" battery has CMOS reset. When I put the TH6887A in the computer and went to BIOS it had the date right but the hard drive was wrong and so was floppy "A". After I reset the 2 hard drives and 2 floppy drives and saved and booted to DOS/Windows it just hung on boot. Any ideas? Pepse.

Maybe this?: http://www.batterytex.com/battery/B... It'd be risky using something other than the one that's already in the machine...

Yeah that place just might have what works. Although you had the wrong battery in the search. That is okay as the do sell the DS1287A, and I think the "A" series will work. I gotta verfy it somewhere as mine takes a DS1287 that they no longer stock. Then too there might be a problem in that if these are old stock they might be junk. But thanks for the link I should help. Pepse.

Sorry, my mistake. Since it's a likely the same as a DS1287, you may want to look at this as well (a case where a rework should suffice, and I tend to save money wherever possible these days): http://www.mcamafia.de/mcapage0/dsr... As mentioned, you could even use an external "AA" or "AAA" battery pack for the 3 volts needed: http://www.bgmicro.com/index.asp?Pa...

Just cut off the pin 21 to let it float. these two chip will be the same function.

First to answer T-R-A; The book for this says mentions an external battery port, but they did not put the pins in the motherboard. There is even a spot there for a Vatra barrel-type battery. Fred Zone, That is like what I am looking for. To modify the other battery. Thanks.