Thanks for all your kind reponses. I've looked at the archived magazines and looks to be just what I needed, although the schematic(s) are a bit 'blurry' and difficult to read.
I never did fit a rechargeable battery, so no problem there.
Regarding the bodge wire, I see on the schematic given that IC14 pin 1 is connected to IC15 pin 1, and nothing else. On my board there is a track from IC15 pin 1 to IC14 pin 12, which is just plain wrong! I wonder if mine was an early version, later corrected, although I have no memory of this.
I did make up a keyboard and LED's to connect to the 8279, but this is on an old RS 'breadboard'; no idea where the circuit came from though, as it's not the same as the real one.
And, finally, having faffed about with the NICE, I've come to the conclusion that it's faulty, since although it seems to work it cannot find any ROM or RAM. Grrr!
I shall burn a few EPROMs with test code and set my Logic Analyser on it!
