Standard 12MHz crystal for keyboard controller ICs (40 pin) IIRC, most of them are based on clones or Intel 8042 microcontroller IC with different firmwares but they tend to work on most boards with any of compatible keyboard controllers.

Cheers,

Oh, my fault!

I thought the RTC was part of it, but the 12MHz crystal is still in perfect condition. We need to trace down, where the RTC crystal is routet to. I could not find any datasheets for the chpset...
SAMSUNG KS83C206
OPTi 82C392
OPTi 82C493
I could not identify any separate RTC / BIOS RAM chip. Still possible, that it is integrated in that MEGA-KB-H-WP keyboard controller and both crystals are routed to it. Need to beep it out, as on the photos no traces are visible from the little crystal.

A little progress is made in cleaning and re-routing broken traces, but the board still does 6x beep, so Gate A20 function is still defective.

Any 32KHz crystals will do, easily found on the modern motherboards.

Cheers,

Some datasheet goodness for the Chipset:

http://www.bitsavers.org/components/opti/data … pset_199108.pdf

I noticed a lot of even the big-name motherboards of the era are pretty much identical to the suggested build in those manuals.

Hope that helps!

Hey guys!

@pentiumspeed: Thanks, will pick some out of the spare parts box.

@ChrisXF: That sure helps a lot to track some connections and understand the signal flow.

Thank you!