Hello,
In this topic i will try to show you how i modified my old A600 to replace your old power brick with any USB-C PD power supply.
Luckily, the 80s/90s were a time where you could find the datasheets written on the hardware itself.
As putting pictures here is quite impractical, i created a Thingiverse page where i put the details i remember (it was a few months long project).
Here it is:
https://www.thingiverse.com/thing:7004514
