In the absence of the original power supply, it is possible to use a mini-jack to connect a 24V DC power source. The jack pinout can be found here. The jack must be not fully inserted, just as deep as it goes without using force, so it does not click. I consider it as a temporary solution only, since the incorrect positioning of the jack will cause shorting the power supply.
SCSI 120MB IBM WDS-2120
Sharp LM64N794. Unlike in most of the vintage laptops, the LCD screen is not removable from the front part of the laptop lid – it is assembled together with the lid used as the support frame.
The original backup battery is 2x rechargeable ML2430. It can be replaced with two CR2430 or smaller CR2032 batteries, soldered together.