More Apple II fun - 4116s...

A word of warning if you want to use all of the 4164 (as opposed to the mods we've been discussing so far that only use 1/4 of it) : Make sure you remove all the decoupling capacitors on what used to be the +5V line in the RAM array, and which becomes the A7 line. Typically there's 0.1uF per chip, and no normal driver is going to drive a 1uF capacitor to ground (i.e. 10 of the decouplers in parallel) without major timing problems. Yes, the is the voice of experience. The Epson QX10 graphics board can be populated with either 4116s or 4164s. There are jumper links to select which ones are fitted,they basically do the pin-swaps we've been talking about. What none of the manuals point out is that if you fit 4164s, you _must_ remove the decoupling capacitors, or you get 'interesting' screen displays. One of my QX10s came to me non-working because the previous owner ad fitted 4164s, had done the link swaps correctly, but left the capacitors in. I spent some time sorting that one out... -tony