Remove that green 3-cell battery ASAP. It leaks, and from your pic I can see it's already leaked through the wires onto the connector header. It can spew the acid further and do some serious damage to your system board.

I don't have really any experience with Direct Access but it worked with DOS, so you most likely have DOS of some version on your ThinkPad.

These caddies can be opened without much hassle (unscrew 2 screws, lift the sides of the sticker, pull out the drive), revealing a standard 2,5" IDE drive. You can hook it up to an adapter and see what's there, and then format or whatever else you please.

stamasd wrote on 2022-01-30, 13:41:

I'm attaching the files for updating the BIOS to version 1.44 (latest) as they can be difficult to find/extract. Files sytpe144.exe and sytpe144.txt are the originals fron IBM, there's also a disk image I made with the extracted files, and a .tar.gz archive of the files contained within that image.

How am I exporting this BIOS file to the 755CX? Copy to a CD? Of course, there are no USB ports.

And once there, how do I move it into the machine? Sorry for the stupid questions, but I'm a real novice with a machine this old.

Manhattanman wrote on 2022-01-30, 20:51:

stamasd wrote on 2022-01-30, 13:41:

I'm attaching the files for updating the BIOS to version 1.44 (latest) as they can be difficult to find/extract. Files sytpe144.exe and sytpe144.txt are the originals fron IBM, there's also a disk image I made with the extracted files, and a .tar.gz archive of the files contained within that image.

How am I exporting this BIOS file to the 755CX? Copy to a CD? Of course, there are no USB ports.

And once there, how do I move it into the machine? Sorry for the stupid questions, but I'm a real novice with a machine this old.

Floppy. The BIOS update floppy image is bootable.
Write that image to a 3.5" floppy disk and boot the Thinkpad from it.

kikipcs wrote on 2022-01-30, 15:17:

Remove that green 3-cell battery ASAP. It leaks, and from your pic I can see it's already leaked through the wires onto the connector header. It can spew the acid further and do some serious damage to your system board.

I don't have really any experience with Direct Access but it worked with DOS, so you most likely have DOS of some version on your ThinkPad.

These caddies can be opened without much hassle (unscrew 2 screws, lift the sides of the sticker, pull out the drive), revealing a standard 2,5" IDE drive. You can hook it up to an adapter and see what's there, and then format or whatever else you please.

Is that 3-cell battery the CMOS battery? If not, what does it power? If it's removed, I assuming it needs replacement. Correct?

I've located a source for this battery.

One other question: If the CMOS battery is bad, going bad or dead, why, immediately after starting the machine did it display the correct date? Very strange. This computer probably hasn't been run in at least 10 years.

Don't worry too much about the CMOS battery. It's made up from lithium button cells. They don't leak.

Manhattanman wrote on 2022-01-31, 00:55:

Is that 3-cell battery the CMOS battery? If not, what does it power? If it's removed, I assuming it needs replacement. Correct?

I've located a source for this battery.

One other question: If the CMOS battery is bad, going bad or dead, why, immediately after starting the machine did it display the correct date? Very strange. This computer probably hasn't been run in at least 10 years.

The 3-cell battery is what IBM calls a "resume battery"; when putting the laptop to hibernation, it would provide power to the (i think) memory to hold the system snapshot, and would keep date and time. Possibly some other stuff. Made to be rechargeable so that users wouldn't have to replace it, and it's a 3 cell so it holds more juice (a regular CR2032/CR1220 would be drained in a short amount of time).
They're nickel-metal hydride, just like those old "barrel" batteries found on older mobos and some Amigas. All my Thinkpads that had this battery (3x760, 755CX) had those batteries already leaked.

In 760s they would damage the right speaker, the keyboard, and TrackPoint, whereas in the 755CX it damages the front I/R cable and could spread down to the system board, where onboard memory and other stuff lies. Here's the damage in my 755CX:

As for the CMOS battery, if it were totally dead, it would complain about 161 and 163 errors, preventing you from booting altogether. Could be that it is on its last legs but still has some juice, and perhaps that Direct Access shell has some function to maintain the date & time and updated it using some point of reference. OR, the date and time was set wrong and Direct Access tries to change the date on its own to have some sort of continuity between the file timestamps?
Other explanations: ghosts, or esoterica. Just thinking out loud here. You could use a multimeter to check the CMOS battery's voltage; that should give you an idea if it's dead or not.

stamasd wrote on 2022-01-31, 01:34:

Don't worry too much about the CMOS battery. It's made up from lithium button cells. They don't leak.

I've been away from the machine for about two days. Medical issues.

When I've checked for battery leakage I haven't found any. That green 3-cell battery looks like an original IBM install. Why do you think it remembered the correct date? Very peculiar.

kikipcs wrote on 2022-01-31, 11:03:

The 3-cell battery is what IBM calls a "resume battery"; when putting the laptop to hibernation, it would provide power to the ( […]
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Manhattanman wrote on 2022-01-31, 00:55:

Is that 3-cell battery the CMOS battery? If not, what does it power? If it's removed, I assuming it needs replacement. Correct?

I've located a source for this battery.

One other question: If the CMOS battery is bad, going bad or dead, why, immediately after starting the machine did it display the correct date? Very strange. This computer probably hasn't been run in at least 10 years.

The 3-cell battery is what IBM calls a "resume battery"; when putting the laptop to hibernation, it would provide power to the (i think) memory to hold the system snapshot, and would keep date and time. Possibly some other stuff. Made to be rechargeable so that users wouldn't have to replace it, and it's a 3 cell so it holds more juice (a regular CR2032/CR1220 would be drained in a short amount of time).
They're nickel-metal hydride, just like those old "barrel" batteries found on older mobos and some Amigas. All my Thinkpads that had this battery (3x760, 755CX) had those batteries already leaked.

Battery.png

In 760s they would damage the right speaker, the keyboard, and TrackPoint, whereas in the 755CX it damages the front I/R cable and could spread down to the system board, where onboard memory and other stuff lies. Here's the damage in my 755CX:

Battery 2.png
Battery 3.png

As for the CMOS battery, if it were totally dead, it would complain about 161 and 163 errors, preventing you from booting altogether. Could be that it is on its last legs but still has some juice, and perhaps that Direct Access shell has some function to maintain the date & time and updated it using some point of reference. OR, the date and time was set wrong and Direct Access tries to change the date on its own to have some sort of continuity between the file timestamps?
Other explanations: ghosts, or esoterica. Just thinking out loud here. You could use a multimeter to check the CMOS battery's voltage; that should give you an idea if it's dead or not.

Thanks for your detailed information. I'll get back in and check battery condition more carefully. Thanks, again.