Does it have an AMI bios like the 5500AT ?

It's not a shock that it forgot about the HDD. That would be expected as soon as the CMOS battery died.

Some of those old Phoenix BIOSes in fact have a SETUP in ROM, but the keyboard shortcut is very tricky. It's Ctrl+Alt+Enter or Alt+Ctrl+Enter or some variant thereof and you can't do it during the memory test like most BIOSes. Instead it has to be done later, when it's trying to boot DOS.

If it lacks SETUP in ROM you'll have to use an external SETUP program, but in any case you must figure out what the right parameters for your HDD are. Have a model number or anything?

If it has forgotten settings then that means the bios battery has lost its charge... If it has lost its charge then it's also quite likely that it may have started to leak - open the case up and check for leakage around the battery; they can easily destroy the motherboard!

Horun wrote on 2023-09-03, 20:03:

Does it have an AMI bios like the 5500AT ?

No, only what I reported above.

jakethompson1 wrote on 2023-09-03, 20:59:

Some of those old Phoenix BIOSes in fact have a SETUP in ROM, but the keyboard shortcut is very tricky. It's Ctrl+Alt+Enter or Alt+Ctrl+Enter or some variant thereof and you can't do it during the memory test like most BIOSes. Instead it has to be done later, when it's trying to boot DOS.

Do those keys need to be pressed individually in some order?

Pressing them together delayed (or seemed to?) the "Strike the F1 key to continue" appearing after "Invalid configuration information - please run SETUP program", but didn't get me into BIOS setup.

If it lacks SETUP in ROM you'll have to use an external SETUP program, but in any case you must figure out what the right parameters for your HDD are. Have a model number or anything?

I do after opening the case again to check: Seagate ST351 A/X. Do I need to know anything more than these specs?

megatron-uk wrote on 2023-09-03, 21:59:

If it has forgotten settings then that means the bios battery has lost its charge... If it has lost its charge then it's also quite likely that it may have started to leak - open the case up and check for leakage around the battery; they can easily destroy the motherboard!

I don't see anything like that. As I said, it's all in remarkably good condition inside.

Nekome wrote on 2023-09-03, 23:26:

Do those keys need to be pressed individually in some order?

Pressing them together delayed (or seemed to?) the "Strike the F1 key to continue" appearing after "Invalid configuration information - please run SETUP program", but didn't get me into BIOS setup.

Yes you press and hold each one, like Ctrl-Alt-Del for a reboot. If AMI is typically just DEL key, Phoenix can also be CTRL+ALT+S. F2 or many things.
Added: I attached Phoenix setup 3v for 286's. Unzip to a bootable floppy and try it
Note: Most 286's do not need a setup disk....

If it lacks SETUP in ROM you'll have to use an external SETUP program, but in any case you must figure out what the right parameters for your HDD are. Have a model number or anything?

I do after opening the case again to check: Seagate ST351 A/X. Do I need to know anything more than these specs?

No you need more info for the HD, example: https://stason.org/TULARC/pc/hard-drives-hdd/ … -SL-IDE-AT.html
Ok that HD has C-H-S: 904-2-17 native and 820-6-17 translated which is what you would use, if the BIOS has drive types then it needs set to one that is equal to one of those set of numbers...
Type 40 if AMI 286 bios or Type 44 if Phoenix 286 bios. (https://www.win.tue.nl/~aeb/linux/hdtypes/hdtypes-3.html)
If the batteries for the CMOS are dead then the BIOS will reset to certain defaults, usually drive type 1 on older motherboards. Does the 5000AT have a battery pack with 3 or 4 AA batteries ?
Most of the early Leading Technology/ PC Partners/Vtechs used a 3 AA battery pack not an on board battery, but not all.
Can you post a picture of the inside of the case ?

Horun wrote on 2023-09-04, 01:18:

Can you post a picture of the inside of the case ?

Certainly! If you want a more detailed shot of anything, let me know.

The expansion card sitting loose at the upper right is a modem which was added a year or so after the computer was purchased and which I have just removed for now. Everything else is original.

No battery to be seen on the right side of the case - check under the hard drive/floppy/PSU side of the case.

You will either have a soldered on ni-cad cell, which likes to leak or a flying lead to a couple of AA or AAA cells in a small external module. Both can cause problems, so check and remove, clean up any issues and then replace.

In fact, that battery "warning" label makes me think you have a couple of cells tucked under the floppy drive. Check those - they are almost certainly flat and accessing the bios to change any value back will be pointless unless those settings can be stored.

With any luck being not on the motherboard they won't have leaked and you can just source a couple of replacements.

Hi.
I'm 99% sure your BIOS does not have build in setup program so "pressing key combinations' will not work.
Check my thread:
(SOLVED) 286 "CHIPS" mainboard with missing parts...
Most likely you have similar / same version of BIOS.

But FIRST OF ALL check the battery (if it leaks, damage to the PCB is inevidable !!!) .
As mentioned above it is probably 'hidden under' HDD/FDD.

Actually, could this be the battery we're looking for?

It's tucked under the overhang of the 5.25" drive. It's connected to a spot on the motherboard labeled "JP2 BATTERY".

The model number is TL-5242/W, which appears to mean it's a lithium battery. Still sound plausible?

(Sorry about the tiny baby steps here, this is a level of electronic detail I've never explored before.)

Nekome wrote on 2023-09-05, 00:40:

Actually, could this be the battery we're looking for? IMG_0415.JPG It's tucked under the overhang of the 5.25" drive. It's con […]
Show full quote

Actually, could this be the battery we're looking for?
IMG_0415.JPG
It's tucked under the overhang of the 5.25" drive. It's connected to a spot on the motherboard labeled "JP2 BATTERY".
The model number is TL-5242/W, which appears to mean it's a lithium battery. Still sound plausible?
(Sorry about the tiny baby steps here, this is a level of electronic detail I've never explored before.)

Yup, If your MB lost CMOS settings, most likely your battery is drained.
Just measure its voltage and you will know 😉

https://www.digikey.com/en/products/detail/ta … L-5242-W/512528

Nekome wrote on 2023-09-05, 00:40:

Actually, could this be the battery we're looking for?

Argh, somewhere along the way the actual photo got lost. Trying again here...

Yep that is the battery pack, it is listed as Lithium non-rechargable so it will be most likely be dead (if below about 2.9-3.0 volts it will not keep the settings, same with a new board), it can also be replaced by a 3xAA cell simple type with non-recharable batteries.

Some old 286 systems cheaped out on the bios by not including the setup program in rom.

The simtel archive had/has a useful program, called gsetup31.zip (In sysutil)

It stands for 'generic AT setup'

You need a bootable dos diskette, but that's fine.

CMOS data is fairly standardized*, so generic setup might work.

*there are some caveats with certain makers/models of system. IBM's ps/1 and ps/2 lines especially, or anything eisa. If this us a bog-standard 286 clone, gsetup should be fine.

Yeah there are dozen or so old setup utils, I posted v3.3 from Phoenix for Phoenix. There is also a v4.03 from Phoenix for Phoenix...

Found a place to order a fresh battery from. Installed it. The old battery pack looks nice and clean with no leakage at all.

No change in the error messages on startup. Running the MS-DOS install again, managed to find my way out of it to a prompt!

Put the disk with GSETUP in the 3.5" drive, and the computer thinks it's blank.

I can't remember if this computer originally could use 1.44MB disks or if it needed 720KB ones. But could putting a high-density disk in a drive that expected lower-density ones cause that?

yes-- it would give you the "Disk not formatted" / "General failure reading drive A:" error.

GSETUP will comfortably fit on a 360k diskette, so if you put tape over the little window on the 1.44mb diskette, and format it as 720K (IN A 720K DRIVE!!), then copy it on, it should work just fine.