That is pretty cool! I'd tossed about the option to purchase an AV mod unit from RWAP - but I figure that this may be the cheaper option given how expensive those kits are... Thanks for posting.
I will need to get a new membrane though - thinking it was well gone, I decided to lift it out. Its pretty well glued (taped) down, and it becomes a 'once you take it off, you will likely need to replace it anyway' type of affair. However it still works, just looks kinda messy now. Doh!
Tuning my ZX81 into the RF worked, but the picture was almost black on black. Some of the kits claim to resolve this, but then I also saw someone mention the emitter-follower approach may also help. Any ideas on this, or perhaps I just try it and find out.
As for transistors, what would you recommend. I have a handful of modern transistors laying about that I used to replace the power transistors in the ZX spectrum, but would they create a problem (ie. overheat, or damage the machine) ot should I go strip some old-school ones from a circuit board?