Part 1 - Starting the Build

Part 1 - Building the Front Board and Motherboard

 

21 June 2023 The Front and Motherboard PCBs arrived and got stuck into populating it. As per normal practice the low profile parts first. Had to be very careful with the LEDs as they are not all orientated the same way. Switches not in yet as the plastic bit on some need to be swapped and the grey ones still need to be printed. Also going to print a support around the switches to help prevent cracking of the solder joint. Panel mounted switches would have been better.

This is the front board, all these LEDs come on without anything connected and actually works!!! Note: The other LEDs have the logic the other way round so need their respective pins grounded, did that and all work. Just haven't tested the one-shot circuit yet. So if nothing else I have an LED matrix board that could do pretty patterns, like those computers in in Star Trek (TOS)

It took a good few hours to finish as there was a lot of double checking of the values and the orientation of each part, hate desoldering stuff. But with that all done it was time to move onto the motherboard. This has only a few components only frustrating part is installing the longer JAMMA connectors. Nothing wrong with PCB or the connector its just a lot of pins (76) to line up. But all good now have to wait for the lost PCBs to be re-sent 😡. 

Building the Timer, Decoder and Accumulator

These three boards make up the next stage and when done some basic tests can be done. Page 26 runs through what tests can be done and involves some temporary cables between the front switches SR0-7 and MB0-7 that way the switches can pretend to be the MB register for a day.

Boards have their IC sockets and all the passives but ....