Keybard repair help. Older terminals

Alexandre Souza alexandre-listas at
Wed Jan 16 18:33:23 CST 2008

> Good luck.. The 9915 keyboard interface is for a matrix-of-switches dumb
> keyboard. I don't know how fast it scans, a microcontorller might be able
> to keep up. The main prolem is that it's not at TTL levels (I think it's
> at 6V CMOS levels).

    Tony, as fast as it could be, just an interrupt onto the first (or in 
all) of the columns/lines and you can scan the entire matrix in sync with a 
microcontroller. Thats what I did in a MSX keyboard converter. And it can be 
done - as far as I know - to any old microcomputer avaiable

    It isn't just a matter of rewiring switches - but the praticity of using 
any PS2 keyboard - and better - the best keyboards you can find. I hear 
someone shouting "IBM MODEL M" from way behind :o)

    Greetings from Brazil
    In a "hardware hacker" day :oD 

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