CDP1802's Quest Super Elf

A cool version of the Popular Electronics classic.

The Quest Super Elf was one of the first commercial 1802-based systems that I seriously wanted. I got a Studio II first, it was practically free at a swap meet alongside some cool cartridges, but I couldn't program a Studio II! Recreating the Popular Electronics articles was a neat idea but I'll be honest, I really didn't want to use toggle switches to enter data. The Quest Super Elf and the Netronics Elf II stood out to me as the things to get, they just sadly cost a pretty penny on eBay (I haven't seen one under $500) so they felt pretty out-of-reach.

A fairly simple computer on its own, the Super Elf is pretty much what happens if you take some common expansions for the COSMAC Elf and roll them onto a circuit board. You've got the same 'ol 1802 CPU, two 2101s for the same 'ol 256 bytes of RAM, an optional 82S123 PROM for a simple monitor, now up to six seven-segment displays for showing the address bus alongside the usual data bus/output register, nine LEDs to show the Q status plus all the different CPU modes/states, an optional speaker, the 1861 Pixie on-board, and a fancy 24-key hex + functions keypad for enterting data. Pretty loaded, eh?

Now, I do have to admit one thing: My Super Elf is a replica. That said, it's a damn beautiful replica. David Madole, commemerating the 40th anniversary of the original Quest systems, made an extremely close (you can tell modern design software made it because it doesn't have curvy traces, it uses Cherry MX keyswitches instead of the vintage bits that would be hard to find these days, past that it's identical) replica of the PCB and even put the gerber files out for free. I didn't know actually know about this until 2023, that said I rushed out of my way to order a board via JLCPCB the second I found out I could.

With my Super Elf all built and working, I'd be lying if I didn't say it's the new shelf staple. It sits right on top of the H11, I take it down pretty often to play around on it, and I couldn't be happier.

Finding a few components to finish my build have proven to be mild challenges but none were impossible to overcome. The notable ones go as-follows:

• The 1861 is an anomaly at this point. As-of September 10th '24, the only sold listing on eBay was $145 + $5 shipping for a single IC. That said, the Spare Time Gizmos 1861 (Bob uploaded the gerbers to OSHPark, get PCBs here) exists or David recently (also as-of September 10th '24) updated Ed Keefe's AVI 1861 and provided all the build files on Github. Both options take a little soldering, the STG is all through-hole while the AVI is all surface-mount, but both options cost way less than $145. You can also just ignore having the thing (or an equivalent) but what fun is that?
• FND500 seven-segment displays aren't made any more but I was able to source a tube of ten (6 + 4 extras for the future) via UTSource, eBay seems to pretty consistently have them as well, and there are a fair few compatible options that also exist.
• The DM9368 and 74C923 are similarly just not made any more, that said the secondhand market has been full of them and so far I've had no issues with buying the things from China (but I do buy an extra or two every time just in case).
• 2101 RAM is old RAM, that said many arcade parts shops (and eBay, etc.) stock them (and sometimes even tested!) for not too bad a price.
• I just outright ignored installing the 82S123 PROM as I didn't want to try sourcing a blank PROM or finding a way to burn the monitor to it. That said, the monitor does sound nice. Maybe I'll get it in the future?

It may not be the easiest build for anyone to just pick up and do due, those harder-to-find parts can take a minute to get, but if you're willing to put in a few minutes (and a few dollars) then it shouldn't be that hard. I spent maybe one weekend to order up all the bits, I spent another weekend to put the thing together, and the only ten minutes of debugging I had to do were because of a cheap barrel jack for my AC input that broke upon soldering. If you want that '70s kit experience without the COSMAC Elf-isms of the Popular Electronics design (the toggle switches for data entry, only two TIL311 displays, needing to add some extra bits for your Pixie, etc.) then I'd seriously consider making one of these. I quite love mine and I'm sure others would have tons of fun as well!

Last Update: 09104-0206
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