Elf99 - rebirth of a classic

I originally wrote: Allison Parent resonds: If I can lay my hands on a quantity of 1822/2101 RAMs, then I agree, even though they will cost as much as the CPU. The 6264 was a fallback. In any case, I would decode 7 or 8 upper address bits if I went with a larger SRAM and allow the user to stick in there what they wanted. One other suggestion is room for a ROM. I could wire in two or three JEDEC sockets and let the builder pick what to go in the, one 62256 or a couple of 6264's and a 27128, for example. The problem with replicating the SuperElf is the keyboard. I have no idea where to get that chip from (74941?), nor an inexpensive source for that many pushbuttons (including some latching ones). I can see the keys coming to $2 to $3 each if bought from a standard vendor. Agreed. I never expanded my Quest Elf. My mentor did, a mature fellow of 16 to my 11 at the time. He shoved in a machined pin wire wrap socket and took it from there. He built his own 8-bit input port and 8-bit relay driver output port by breadboarding the standard 44-pin Radio Shack prototype boards. It worked, but it was non-trivial. I inserted the WW socket, but never wrapped anything to it. Me, too. There are a couple ways of implementing expansion, Elf-II compatible and COSMAC VIP compatible. The VIP used those ubiquitous 44-pin cards. I would rather build in a compromise of universally desired features than get into the position of making peripheral cards. In practice, I like addon cards, but when it comes down to a very small production run, I'd like to keep this to one board. Cards are nice when you have lots of users with very different needs. With an Elf, beyond an I/O port and serial or video, what's really necessary? What's so important that it raises the cost a few bucks for everyone? I was thinking of extras like an area for the 1861 video, or a 2"x4" perfboard prototyping area. In any case the Quest design wouldn't be that expensive in sufficient quantities, but at q. 25, there's a lot of setup charges to amortize over the small run of the boards. At least $10 each (~$250 setup / 25 boards). If anyone can direct me to a board house that will do a 6"x9" board with ~600 holes, three or four sizes, plated through, with minimal setup charges, I'm all ears. Unless I get *lots* of interest, I'm only considering a run of 25, then that's it. I don't want to have 60 or 70 unsold boards hanging around forever. 40 pin CPU, 2x22 pin RAM, 11 switches, 2x7 pin displays, approx 10 CMOS DIP parts x 14 or 16 pins, a handful of diodes and resistors... let's say about 350 point-to-point connections, probably more. I breadboarded, but never more than about 200 connections, and that was a DEC FLIP-CHIP module tester for the VIC-20 (dual 6821 PIAs and a single DEC 36-pin backplane connector). The Quest kit was the base ELF plus a ROM socket and space for primary and secondary power supplies. One suggestion for the Elf replica was to use a standard 4-pin Molex connector and power it from a discarded PC power supply. The Quest Elf kit just had two solder pads for 6.3V AC or +5V DC. I ran mine from my VIP regulated +5v supply. -ethan