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Testing: Building a sound board test rig (part 1)
So.. we need sound and I need a way of testing the boards I have to see if they work, but actually switching them in and out of the main Defender cabinet is a really slow process. Therefore – let’s...
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Testing: How to basically test your Defender board set
From a post I wrote on UKVac to hopefully help another user “Is anyone on here able to test my defender boardset for me? It shows lines down the screen and has never booted properly and the old owner...
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Testing: Building a sound board test rig (part 2 – with video :-) )
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...
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Testing: Building a Williams Test Rig (part 1 – board layout)
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...
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Testing: Building a Williams Test Rig (part 2 – interchangeable power supplies)
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...
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Building a dual Williams Defender and Williams Stargate Control Panel [Part 1]
So I’ve been meaning to build a replacement control panel in order that I can take off the main control panel and replace the leaf switches with new more responsive compatible pinball leaf switches....
View ArticleDefender ROM Versions – The history
One of the cool things about spending a lot of time learning how to rebuild the Defender machine, is that you soon build up a fair amount of knowledge about how it works and the history behind it. So I...
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Upgrading: Replacing the 4116 memory with 4164 memory
It’s a well documented fact that the standard 4116 memory used for the Williams games such as Defender gets very hot and fails often, and also requires multiple voltages to work, which make them a...
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Testing the 4116 memory
One of the questions asked quite a lot with Williams boards is how to test the often failing 4116 memory chips Well the good news is that the 4116 shares the same 100% compatibility with the NEC...
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Testing the Chad’s Arcade Defender Memory High Score Save Chip
Our very nice friends at Chads Arcade sent over a couple of their Defender High Score save chips so that I could test them on our Defender machines at Skywire And these kits are great – replacing the...
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