Had a bunch of these years ago and I'm going off memory but try this:

The top label is covering a pair of screws. Peel back the label slightly and remove the screws, there are nuts in the other side that will fall out too.

Then IIRC, you can get the rest of the caddy apart by carefully prying the plastic tabs away on both sides. I don't remember this requiring a lot of force so just do everything gently.

Hello DamienC,

Your memory is great, it worked like a charm, thank you very much. However for me it was not easy to pry the plastic bars =) :

Now the best part, the PC doesn't boot, so the fun begins. When I turn on the PC I get stuck here:

I get stuck with the message 07808 kb ok.

When I ran the diagnostic in the BIO :

I get this error on the HDD, DEV 017 Err 01 FRU 6010. Where do you find information about these code errors?

The compact flash I am using is this one, 16GB version:

https://www.silicon-power.com/web/zz/product-CFI320

The CF to IDE adapter is a generic one :

https://www.ebay.fr/itm/303108372252

When I connect the adapter to the PC, 6 pins are not connected, maybe I have chosen the wrong adapter?

There's a jumper on the CF to IDE adapter, not sure if it may be useful :

It states that Jumper 1-2: Master/Slave and 2-3: Slave/Master. Now I am just trying to understand what position is set, on the back there are no numbers :

Before trying to replace the Hard Disk, there was already an IBM DHAA-2405 running PC-DOS without any problems.
In the Compact Flash there's a FreeDOS 1.3 installed. It was installed through VirtualBox which created an image of the disk, .vhd and I just "burned" it into the compact flash. When I connect the Compact Flash, I get stuck in during the boot, I can't even boot from the floppy disk, however if I disconnect the compact flash, I can again boot from the floppy disk.

From what I read online:
- the size of the Compact Flash may pose problems. For now I don't have another CF so I cannot test it
- updating the BIOS may help.

I will try :
- to find out what these errors mean in the BIOS
- trying to understand what position is set with the jumper on the adapter card
- if someone can lend me a smaller compact flash
- find out how to update BIOS

In the meantime if someone has a clear idea about this problem, I will appreciate any comments on it.

I think the problem is the CF card. These Thinkpads usually work with drives no bigger than 8Gb iirc, maybe even smaller. So I'd try another card. Mine works with a 2 Gb CF. The brand of the card also matters, it sometimes gets tricky to make them working.

Error codes can be found here https://download.lenovo.com/ibmdl/pub/pc/pccb … iles/tpvol2.pdf

Try a 2GB formatted with FAT16

Those hard drive cases are hard to open.
I remember I upgraded mine with a larger capacity IBM hard drive not a CF card.
Their might be a problem with the Thinkpad bios boot up diagnostics and the CF card because the Thinkpad bios Checks the hard drive for functionality on boot up.?

Either way the think pad works fine with a regular mechanical hard drive.

Thank you for the replies.

I tried a 2GB formatted with FAT16 on the same disk CF 16 GB but it didn't work.

I have a friend who might be able to lend me a CF 1GB. Otherwise, I think I'll just use the hard drive, as I don't want to spend money on CFs at the moment until I get one that works.

In this post I can see that a Kingston compact flash 1024 MB works just fine,
Re: 486 Thinkpad with genuine Sound Blaster Pro 2

However I cannot find one in Europe at a reasonable price.

Bondi wrote on 2024-03-02, 07:08:

I think the problem is the CF card. These Thinkpads usually work with drives no bigger than 8Gb iirc, maybe even smaller. So I'd try another card. Mine works with a 2 Gb CF. The brand of the card also matters, it sometimes gets tricky to make them working.

Error codes can be found here https://download.lenovo.com/ibmdl/pub/pc/pccb … iles/tpvol2.pdf

Which one do you use Bondi ?

Here's the one I use. What can also matter is how you create the partition and make the card bootable. Try doing it from scratch(delete existing partition, create a new one, format/s) on the oldest computer you can. Ideally in pure DOS.

EDIT: I use the same CF/IDE adapter, and the jumper on mine is set to the same position (closer to the IDE pin header) as on your photo above.

Thanks Bondi.

Tried to create the partitions again and format as you suggested but no luck. The oldest PC I have available is from 2017.

In the meantime my friend lent me a Compact Flash EMTEC 2GB 80x and it worked perfectly fine =)

Well, I still need to find one for me but I would say the problem is solved.

Thank you everyone