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 comes with the following separate boards

– CPU/Video board

The main grunt board that contains a 6809e processor for doing all the work, and a chunk of RAM as Dynamic Ram (16K x 24) [yes kids that’s a total of 384K which is less than a 1/3 of a 1.4Mb floppy disk] and CMOS RAM (256 x 4!) . A 6809e processor is about as clever as the chip that runs your heating timer (or something like that!) 🙂

– ROM board

This contains the ‘game’ data, so all the instructions to make Defender well basically, Defender and has 11 ROM chips which store the data. There were/are 3 different editions that were labelled with White, Red or Green stickers

– Interface board

Collects together all the inputs (joystick, coin mechanism, buttons etc.) and feeds them back to the rest of the boards

– Sound board

Generates the sounds. Interestingly (well kinda…) Williams used these boards fairly the same across their pinball machines and arcade games so there’s lots of revisions of them, but they all seem to be fairly interchangeable

– Monitor

Shows the nice pretty graphics on the screen

– Power board

Turns 110/240V into lots of other voltages for the boards above to use, and light the marquee etc.

So here’s what we have:

CPU – White labelled ROMS, no corrosion on the battery holders at the bottom (* a good thing) and serial numbered 494903 and labelled 1981 Williams

CPU - White labelled ROMS, no corrosion on the battery holders at the bottom (* a good thing) and serial numbered 494903 and labelled 1981 Williams

ROM (bottom) and Interface Board (middle) – Labelled 481368 and 502941 and by the look of the ROM board some replacement non-original chips in there [don’t worry we’ll fix that later]

”]Sound board (top) – labelled ‘Video Sound ROM 1980 Williams’ and serial numbered 491004

“]

Sound board (top) - labelled 'Video Sound ROM 1980 Williams' and serial numbered 491004

Power – Wow this needs a serious clean/hoover as does the whole machine.

Power - Wow this needs a serious clean/hoover as does the whole machine.

Monitor – No picture as no monitor yet – we need to get one! I have been advised that a SCART TV can be used as a temporary substitute, so funnily enough found one abandoned while walking the dog so popped it in the boot of the car and will test if it works this weekend!

Next Steps:

A bit of a change of plans in that rather than focusing on tidying up the externals of the cabinet, I think the next priority is to tidy up the inside and try and get the whole machine working. Luckily I’ve got spare ROM boards, spare CPU boards, replacement new power supplies, extra I/O boards and even a spare sound board, so we MUST be able to get it working some how!!

First next step. Clean the power supply and convert from 110V (US) to 240V (UK) – there’s a good forum post about this so I’ll update as I go.