Reply 220 of 283, by snufkin
Looking around at jumpers near other KBCs, I think JP23 is probably reserved-keep open. The jumpers that crop up near KBC seem to be mono/colour, power save, CMOS battery related, and reserved. There's a Mitac board here that has the silkscreen "Reserved, Open": https://www.ultimateretro.net/en/motherboards/7208 where someone tested that it went to P16 on the KBC, which on the Intel 8042 is pin 33. So that matches yours.
That board may help a bit for IDing the remaining jumpers as it's also got an 822 fitted, although the main 2 chipset chips are different.
I've also finally realised that the CPU options given on your board (P60,66,90,100) will be talking about the original 5V Socket 4 P60/66. So that silkscreen now makes sense to me, with JP33 used to turn on Socket 4 and turn off Socket 5 when using a socket 4 P60/66. Nothing to do with a multiplier at all. I'd somehow got it in my head that this was a 486/586 socket 3/4 board (since the chipset can apparently handle both) and not a Socket 4/5 board.
Wonder if there's any way to adapt a 486 to work in a socket 4. Most of the pins are there.