A few days ago I posted about my old PC and there was some interest, here's an update.
tldr: the hdd saved everything! It has windows 3.1 and all the games I remember are still there.
Longer story:
I bought a few adapters for PATA/IDE to USB and they didn't work. I had this weird issue where when I plugged the usb into my computer, the drive would power off. You can hear it spinning when it's on, plug in USB, drive powers off. Unplug USB, drive powers back on. So after buying 2 different adapters, I gave up on trying to read it that way.
Then, I got a floppy reader and a bunch of floppy disks. The software testdisk has a DOS version, so I copied that to a floppy and ran it on the computer. While it was analyzing the HDD it told me in an error message that the drive appeared smaller than it actually is, and I should update my bios settings.
After struggling to figure out how to get to bios (ctrl alt s, AFTER BOOTING), I googled my drive model and found the cylinders, heads, sectors information and manually typed that into the BIOS as a "user defined" hard drive, and that was all it needed to be able to read the drive.
After that it booted straight into PC DOS + Windows 3.1 and everything is there. I found recipes, games, and other programs.
I was going to try to send files over serial, but it wasn't working for me (i still haven't tried zmodem yet) but I couldn't even receive an echo to the serial port. So I've been backing things up by copying to floppy disk, then reading the disk on my laptop with a reader.
I bought a few adapters for PATA/IDE to USB and they didn't work. I had this weird issue where when I plugged the usb into my computer, the drive would power off. You can hear it spinning when it's on, plug in USB, drive powers off. Unplug USB, drive powers back on. So after buying 2 different adapters, I gave up on trying to read it that way.
This sounds like the PSU doesn't have enough watts to go around when you're plugging in a USB device that draws power. You might be able to get USB devices to work if you use a powered USB hub.
No, the reason it doesn't work is that IDE to USB adapters don't support pre-LBA HDDs. These old disks are all CHS-addressed.
I wanted to take images of such disks. I ended up managing to boot an ancient version of Knoppix from a CD (just booting it was a nightmare) and then using dd_rescue to clone it to a file on a CF card connected vi a CF-to-IDE adapter.
Edit: oh, drive powers off when usb is connected? Might be that the adapter doesn't offer enough power, but if you could get around this you would inevitably run into the problem I describe above.
If the drive is spinning when the USB is not plugged in then it's clearly being powered by a separate power supply. Besides, 5.25" hard drives cannot be powered by USB, powered hub or not.
... No. The computer has one power supply, and old computers from PB, Gateway, Dell, would have power supplies that produced barely enough wattage to run the hardware it sold with.
You add another device, with its own power draw, and if you go over the limit of what the PSU is able to supply, something gets underpowered and misbehaves.
Using a powered hub means that the power sent to the USB device is provided by the hub, and might make it so that OEM PSU is still sufficient. Here, though, we have already added an ISA>USB card.
Another option is putting in a higher wattage PSU, but I don't know what the connector used was on that machine. It might be hard to find something that would just plug right in.
Oh and the reason you had to enter the HDD settings is because the coin-type BIOS battery died. Replace it, or you're likely to have to do that every time you turn it on.
Then the cmos battery is probably in a Dallas DS1287 or similar chip. There are hacks to replace the battery itself with a CR2032 holder, but it requires drilling into the chip.
I bought a DS12887+ to replace it, and socketed it in case it would need replacement again in the future (in another 30 years? :)). But if you want to go this route look up what chip is compatible with the exact one you have.
If you have a parallel null modem cable (or even a serial one) you can use the dos interlnk and intersvr command to access the drive from another computer. Not sure if that will help.
Entering the CHS values into bios was common practice on pre pentium level computers. This might explain why your usb adapter doesn't work as the drive is too old to send its geometry.