Archive for April, 2014

Testing: Building a Williams Test Rig (part 2 – interchangeable power supplies)

Apr 29th

Posted by Judder in Power Supply Unit

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In order to keep the Williams Defender harness I have as original as possible, I don’t want to replace any of the original connectors so instead we are going to make the linear PSU and the original Williams PSU totally switchable using connectors. 1. Acquire male and female ATX connectors The number of wires used,…

Testing: Building a Williams Test Rig (part 1 – board layout)

Apr 29th

Posted by Judder in Testing

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In order to test our Williams CPU, ROM, I/O and Sound boards I’ve decided it’s time to invest some time and effort and build a complete Williams Test Rig. The goals of the rig are: – Allow testing of all Williams boards (CPU, ROM, I/O, Sound) – Allow testing of all Williams games (Defender, Stargate,…

Testing: Building a sound board test rig (part 2 – with video :-) )

Apr 22nd

Posted by Judder in The Boards

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So we have the sound board correctly powered with +5V, +12V and -5V, speaker connected and volume control turned up, so the final task is to simulate sound triggering from the CPU by grounding some of the input pins on IOJ3 (top right of sound board) from 2 to 8 (1 is key and 9…