you maybe able to take the floppy out of the laptop and take it apart and clean it. It sounds like a bad floppy drive. But I would get the floppy drive working 1st, and id remove the harddisk totally. Get to the point that it will boot from a floppy. After that you can trouble shoot the HDD drive, or possibly ram failure. Baby steps.

Thanks, so I opened floppy drive, and looking pretty good and clean inside. Did a simple head cleaning and sightly oiled screw shaft, still not booting. Guess I should try to clean/reset a motherboard next

Ok, so while I have no options to boot, I ordered CF to laptop IDE 2.5 adapter, and PCMCIA to CF card too. Hope these will work on such an old machine, they are very cheap anyway.

Disassemble the whole laptop and check if the standby battery has leaked onto the motherboard.
Check for dried out caps in the power area of the motherboard. Sometimes leaving the system on the charger for a day does do wonders too.

I suspect your motherboard has some issues which makes this happen, find the problem, fix it and enjoy your system!

Nvm1 wrote on 2020-09-27, 19:49:

Disassemble the whole laptop and check if the standby battery has leaked onto the motherboard.
Check for dried out caps in the power area of the motherboard. Sometimes leaving the system on the charger for a day does do wonders too.

Thank you for your advice, I already disassembled the main board(several boards in fact), with no luck and same symptoms.

But then I realized I never saw CMOS battery, turns out it's on the keyboard card, along with a second rechargeable battery, speakers, monochrome LCD and all schematic for it too. Never saw so many thing in just a keyboard, looks a little bit over-engineering with 9 connectors on one lower board.

So yeah, definitely some leakage and oxidization going of there, but both batteries are clean soo not sure about the reason. Looks like water damage with long exposure, even screws are rusty inside. Now I have almost no hope for this part, but will try to clean it anyway.

Yeah, vinegar make wonders, same copper foil after some soaking and zero rubbing

So I am assuming you acquired these:
drivers: https://thinkpads.com/support/Thinkpad-Driver … /ddfm/765d.html
manual: https://thinkpads.com/support/hmm/hmm_pdf/vol4hmm.pdf

Page 444: I9990305: No bootable device.

Akuma wrote on 2020-11-09, 21:07:

So I am assuming you acquired these: drivers: https://thinkpads.com/support/Thinkpad-Driver … /ddfm/765d.html manual: https://th […]
Show full quote

So I am assuming you acquired these:
drivers: https://thinkpads.com/support/Thinkpad-Driver … /ddfm/765d.html
manual: https://thinkpads.com/support/hmm/hmm_pdf/vol4hmm.pdf

Page 444: I9990305: No bootable device.

Yes, not the driver part yet, since it's not booting. Same thing with IDE-CF adapter, starting to boot and then turning off. Then 2 beeps every time when I try to power on (system board) until all power disconnected.
PDF manual especially useful for screws, since I found some missing inside and couple of them almost ruined during unscrewing (threads corrosion).
Note: Make sure you use the correct screw and tighten the
screw to the torque specified. Do not use the screw that you
removed, use a new screw

I'm taking my time with cleaning now, but with that kind of hidden water damage chances are low. Not going to resolder anything yet, I didn't expect it to be so cramped and small for 1997 to be honest, not much difference from modern laptops.

When it does enter the floppy/hdd boot process, that connection is there.
Based on the symptoms you describe:
* not enough power goes to the bootdevice, power it externally if possible.
* a broken wire or trace

Akuma wrote on 2020-11-10, 14:18:

When it does enter the floppy/hdd boot process, that connection is there. Based on the symptoms you describe: * not enough power […]
Show full quote

When it does enter the floppy/hdd boot process, that connection is there.
Based on the symptoms you describe:
* not enough power goes to the bootdevice, power it externally if possible.
* a broken wire or trace

Yes, that was my first thought about lack of power, but then I tested old HDD in BIOS and it's working fine and loud for a couple of minutes. Symptoms are the same with CF-IDE too, switching off after 2 seconds, doesn't matter if it's bootable or not.
After some more cleaning and reattaching now I get DSP error sometimes, but DSP card looking ok.

Found nice video about cleaning the same keyboard card https://youtu.be/VKGcxszb3aQ, but in my case it's much worse I afraid.
This green Ni-Cd battery is a real board killer, more people should know about that.

So I took some photos of the traces I already cleaned and calling it quits, they are terrible and these errors likely won't go away until ultrasonic cleaning and resoldering, and I already got another one working Thinkpad. Will keep this one for parts.

ujav wrote on 2020-12-06, 02:18:

Yes, that was my first thought about lack of power, but then I tested old HDD in BIOS and it's working fine and loud for a coupl […]
Show full quote

Yes, that was my first thought about lack of power, but then I tested old HDD in BIOS and it's working fine and loud for a couple of minutes. Symptoms are the same with CF-IDE too, switching off after 2 seconds, doesn't matter if it's bootable or not.
After some more cleaning and reattaching now I get DSP error sometimes, but DSP card looking ok.

Found nice video about cleaning the same keyboard card https://youtu.be/VKGcxszb3aQ, but in my case it's much worse I afraid.
This green Ni-Cd battery is a real board killer, more people should know about that.

So I took some photos of the traces I already cleaned and calling it quits, they are terrible and these errors likely won't go away until ultrasonic cleaning and resoldering, and I already got another one working Thinkpad. Will keep this one for parts.

Yeah, those are the basic procedures:
* Clean and do a solder reflow
* Reconnect broken traces

I usually use a a sharp knife on the broken traces, to scrape off the protective layer, then solder a bridge. Sometimes a small wire is needed, because the gap is too large.

Well, if its a job cut your losses, but if its a hobby project I would still try.
You can always use it for parts if it doesn't work out anyway, why give up on it ?

I learn the most on difficult problems 😁