The Defender Project
The restoration of a 1980's Williams Defender arcade machine
Upgrading: Replacing the 4116 memory with 4164 memory (the Matt Osborn way)
Oct 29th
Matt’s site is now offline since I quoted it in my initial 4116 memory to 4164 memory post, so I have reproduced it below as I was checking the information myself to test some boards. 4116 to 4164 (and/or 41256) mod for Williams CPUs If you want your Williams games to run reliably then you…
Testing the Chad’s Arcade Defender Memory High Score Save Chip
Jun 11th
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 need to have the 3 x AA batteries, or CR2032 battery conversions on the main motherboard by…
Testing the 4116 memory
Jun 11th
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 D416C-2 4116 16Kx1 RAM chip, which was used on the ZX Spectrum Here’s a nice picture for reference…
Upgrading: Replacing the 4116 memory with 4164 memory
Dec 17th
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 hassle to maintain One common upgrade is to replace the 4116 memory (64k memory needing +5V, -5V and +12V) with…
Tron: Testing the Audio Amplifier
Aug 10th
I’ve been struggling with the sound in our Tron for a few weeks now, so decided to isolate the external sound amplifier and test it, to prove whether it was working or not. Thought that it would be helpful for all the other Tron owners to document how to do this – and a handy…
Defender ROM Versions – The history
Jul 24th
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 recently updated a post on KLOV with the correct information about the 3 different production…
Building a dual Williams Defender and Williams Stargate Control Panel [Part 1]
Jun 10th
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. Thus I have hatched an evil plan to build a dual Defender AND Stargate compatible control panel to use while I…
Testing: Building a Williams Test Rig (part 2 – interchangeable power supplies)
Apr 29th
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
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
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…
Testing: How to basically test your Defender board set
Mar 19th
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 said the sound had failed before I bought it.” The sound board and the interface boards…
Testing: Building a sound board test rig (part 1)
Dec 11th
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 build a sound board test rig and we can go through all the boards we…
The Boards: Repairing the sound board
Nov 19th
Interestingly the sound boards for the Williams machines of this era, are basically stand-alone mini-computers that are just triggered with which sound to play, by the main CPU board. Think of it kind of like a door-bell, where you can press different buttons to get different sounds as you go down the street. So I…
The Boards: Defender is Alive!
Nov 14th
So I decided that without a working set of a Defender boards it was going to be impossible to progress the machine further, as not having any control test for the boards we have meant that guess work and luck was about the best we could hope for. So I got in touch with a…
Power Supply Rebuild: Installing a new 230V Power Filter, Varistor and Fuse
Oct 28th
So I did this part of the power supply rebuild a while ago, but never really documented “how” I did it, so thought adding this would be informative to complete the loop on what you need to do. Here’s the existing power filter and varistor as it arrived from the US: Power Filter = grey…
Converting the Neon marquee light for UK voltages
Oct 27th
So it turns out that not only are the US Williams machines of course rigged for 110V, but also the 110V they use has a different Hertz cycle from the 230V we use in the UK. UK 230V runs at 50Hz and the US 110V runs at 60Hz, so even with our Transformer doing the…
Power Supply Rebuild: converting the wiring harness for 240v rather than 110v
Oct 27th
I forgot to document the key part of the conversion process of taking a US Williams machine and converting it from 110V to 240V is that a jumper wire in the wiring harness needs to be moved and another removed to supply difference voltages to the transformer. Below is the default US wiring of the…
Problems with Defender / Stargate continually crashing
May 25th
So I’ve hit an issue where running the cabinet with the Stargate boardset installed, crashes with the ROM board error code 1-3-4 (the display counter flashes 1, then 3, then 4 in a repeating sequence until it reboots). According to the manuals this represents a RAM error (the one) in RAM row 3 (the 3)…
Phoenix (a side project) – board repair
Mar 24th
A bit of a side project, but I’m also repairing the 3 Phoenix boards I have at the same time – so this page is more of a reference of where to find everything you (*and I!) need if you’re trying to fix your own boards. Phoenix repair logs Detailed repair logs from others of…
The boards…
Sep 18th
I’ve been a bit quiet about this one, as I’ve struggling on and trying to get things working, but what I thought was going to be the easiest bit of the restoration (*namely getting the boards themselves to work) actually seems to be the hardest by far! The two main boards, namely the ROM board…
Raspberry Pi: Running Defender with Advanced Mame
Sep 14th
A minor diversion while I am working on the actual ROM boards for the Defender arcade machine, was to get Advanced Mame to compile on my new Raspberry Pi and to run Defender on that (You never know it might make a good back-up to put into the cabinet if the ROM boards get too much…
The Monitor [complete]
Jun 5th
No screen = no picture to play the game on so our next challenge was to find a suitable screen to fit the cabinet. The size is fairly standard at 19″ and a few chats to the helpful team on UKVAC offered up the following standard 19″ arcade screen on eBay for a nice price…
Power Supply Rebuild [complete]
May 13th
So I’ve decided to fight my fear of 240V mains electricity and put some trust in my rebuilding of the Transformer and Power Supply board and plug it in and start doing some output voltage measuring. First thing was to replace the broken bracket that holds the cut-off switch for the cabinet back-cover being removed,…
Control Panel rebuild [complete]
Apr 29th
Finally got some time to work on a few more parts of the project (I’d like to blame work but actually it’s more the fact that I managed to accidentally buy a Tron arcade cabinet in between, but more about that later…) and all the parts had arrived from around the world for the Control Panel so…
Power Supply Rebuild continues
Apr 13th
So I ordered the parts I think I need from Farnell / CPC and they have arrived so now it’s time to try and get the power supply working. First out of the box is the nice new power filter (I had to spend at least £30 with Farnell so thought I might as well…
Power Supply Rebuild begins
Apr 4th
Right – I’ve been making (slow!) progress and cleaned the whole PSU, tested all the fuses and connectivity of their mounts of the circuit board and am ready to re-assemble. Googling the ‘what I thought was a resistor soldered on the front of the Power filter’ it is a GE V130LA10AD Voltage Dependent Resistor and according to the GE…
The Rules – A Sympathetic Restoration
Apr 3rd
So things are progressing nicely – there’s some updates on the monitor, the Power Supply, the control panel and a number of other pieces on their way from the US at the moment – but I wanted to write some rules for the restoration just so I’m clear what I’m trying to achieve. 1.…
Connecting it all back together…
Mar 26th
The eagle eyed of you may have noticed that the wiring loom (basically all the wires that connect everything together) was disconnected from all of the boards as the previous owner’s intention was to sell it for parts. There are a number of ways to fix this and reconnect everything correctly: 1. Follow the schematics…
So What Have We Got?
Mar 23rd
Everything is taking a little slower than planned, but hey I’m in no rush and this thing was built over _30_ years ago (so it’s obviously in no rush either) so let’s start by taking a few photos of what we have. For those who aren’t familiar with Williams machine setups suchs as Defender, it…
The Unwrapping
Mar 16th
It feels like Christmas at Skywire Studios as we’ve finally managed to de-crate the newly acquired Defender machine, and with the help of the team we’ve carried it up 2 floors (4 flights) of stairs and into the office kitchen. The cabinet looks like it has been wrapped by a very large airport suitcase wrapping…
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