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The big PC Board


A long long time ago (40-45yrs) we selecting desk top computers( before PC’s) to do some scientific monitoring.  We concluded the I/O for this project needed to include RS232 Communications with modem, 16 channels of analog input, 8 channels analog output, 16 digital inputs, 16 digital outputs, among other sundry features.  None of these features were available in even a single chip format.  The board size was 16” s 16”.  The board manufacturer had only 2 sided technology, and was concerned about the manufacturing reliabilty of traces less than 40mm.  All IC’s that were available had 100mm spacing and 50mm pads Well I set out to do the impossible, with out any layout software available, The layout was done with red and blue transparrent tape at a 4x scale.  The two sides of the board were photographically separated and reduced (quite a feat in itself)  Well the board worked after only 10 cuts and jumpers and the design served for over 10 years 100/s of boards were made.  Nothing like the way a circuit is designed and boards layed out in the era.  Wish I still had a picture of the board

- Shared October 11, 2012