^^^^^^^^ That's an term I prefer to reserve for HP calculators :-) How far have you got into this one? (Note : I've never seen one AFAIK, certainly not been inside one). I do have a TI 1250, which I've jsut opened uop, and that may be similar. Can you see how many connections there are ot the keyboard. In the 1250, there are 10 bare single-strand wires going to the top edge of the keyboard unit. That's it. Since it has 24 keys, it's a fair bet that thats' a 6*4 matrix (6 rows + 4 colums = 10 wires total). While it's possible for the logic to handle one or two keys in the IC to fail, it's much more common for an entire electical row or column to not work. So if you've just got a couple of dead keys, and that's not an enitre row or column (2 way multipexed keyboards have been used in calculators -- the Sinclair Cambridge, for example -- but they are not that common), then it's much more likely the fault is with the keyboard. Certainly in the 1250, the keyboard does not look easy to take apart. It appears there's a metal strip for each row, cut/formed to make the domes. The plasci keyboard pase carries the column wires, the row wires are then connected ot the apporpriate strips. There are various layers stuck over the top, carefully peelign them up at one corner told me that going much further was not a good idea, I was likley to bend the metal contact strips. If you cna identify which ae row and which are column lines to the keyboard (in the 1250 the column lines are centred on each physical column of keys), you could try shorting each row to each column (with the thing powered on). If you can get '4' and '6' that way, the fault is the keyboard. If not, it's likely to be the IC. -tony