@amigadave
If some keys are working while other don't it's probably a membrane problem. Instead of buying another keyboard or trying to find someone to fix it for you you could try a little trick in the meantime. Just try and cut 0,3 cm (or maybe less if you can) off the membrane part that slots in the keyboard clip of the A600 motherboard. This way, you could resurect the keyboard in case the membrane is "worn out". You have really nothing to lose since the keyboard is dead at the moment. You could give it a try but for this purpose a very sharp and quite "accurate" paper cutter is needed in order for the cutting to be precise. Use a ruler and some adhesive tape in order to keep the keyboard from moving, place it on a steady surface and do the surgery thing
I have done the same to an A1200 keyboard and i'm very happy with it right now. Just keep in mind though that you should be patient and precise if you decide to go this way.
