I have this motherboard too, the SY-016A / SY-019B - I don't know which one of the two because the manual does not describe the difference of these boards. The original manual also describes the type SY-019C. Anyway, I bought this computer 25 years ago, february 1992. It is still in its orginal mini tower with led display. It is not 100% orginal but the video card is, a Tseng Labs ET4000. I replaced the I/O controller back in the 90s with an UMC type.
About 5 years ago the battery was replaced by a new one because the old one started to leak and damaged the board a little bit. At that time the board gave BIOS or Keyboard errors and was not reliable anymore, so I gave up. A few weeks ago I decided to power the system up again, and ever since its running so smooth ...
So I decided that the battery should be replaced by an external one before this one is causing damage too. I checked the manual and noticed that there is an option to connect an external pack of batteries, but there is no information about what kind of batteries should used. I found this thread and to my big surprise there is a pictured attached that shows an external pack .... So my question is, what type of batteries should I use for my mainboard ? (and what type absolutely not ?). Any help is appreciated.