Sharing IC MFD(ways to find the MFD of unknown keyboard)

[terrycherry]

Sometimes we don't know the keyboard model, FCCID and can't find any date both on case and circuit board.
I advice you should checked all ICs on circuit board.

Here's the electronic component's supplier homepage, it allows you find out the information of IC including MFD, Manufacturer and region. Their database should contains the ICs which made from late1970s to now.
http://www.brokerforum.com/

After the checking works done, you should determine the introduced and discontinued date of the switch and manufacturer.
And then check all stuff inside keyboard(including keycaps or thick case etc.) in details which were widely use from 70s, 80s, 90s possibly.
Finally, you"ll know the nearly MFD of the keyboard.