RTL Logic

[Michael Holley]

My goal on the Tic Tac Toe machine was to build an exact replica of the Don Lancaster 1971 design. I have 2 of the MC789 inverters so I could build one unit.

I could change the design to use a TTL open collector inverter but it would be nice to have the exact circuit board.  If I switched to TTL I could make the board or a kit available. (I figure a total market of under 10 units.)

The other item of a exact replica is the lamp color filters. The company AMP Hexseal still makes the filters (No.1813-27). I wonder how much they cost?
http://www.apmhexseal.com/lampfilters/filters.htm

After two years of looking a found exact replacement JFET transistors (TIS58) for my TV Typewriter restorations. The generic replacement JFET worked but it is nice to have the exact part.
http://www.swtpc.com/mholley/CT_1024/CT1024_Index.htm

I got these parts on eBay for  $1.35 plus $2.70 shipping.
13 TIS58 16 TIS97 7 L7805CV 2 L7808CV 4 L78N08 5 78L05A 

------------------------------- 
Michael Holley 
swtpc6800 at comcast.net 
www.swtpc.com 
-------------------------------