MCM66128L20

[Tony Duell]

> 
> I believe (though have not verified it myself since I utterly despise the 
> machines) that Sinclair used this technique in the early Spectrums; they, 
> apparently, simply disabled the faulty half of the DRAMs using jumpers on 
> the board.

I beleive (although, like you I've not checked because, also like you, I 
have as little to do with Sinclair machines as possible) that early 48K 
SPectrums had 8 16K chips and 8 32K chips. The latter were half-good 64K 
chips, there was a link (or maybe a resistor) on the PCB to select which 
half would be used. Needless to say all 8 chips had to ahve the same half 
good.

-tony