Atari Test Rig

overall

Here's something else that I knocked up just recently. I seem to find myself working on nothing but Asteroids boards mostly these days but every now and again other stuff comes in to be looked at. As it happens most of these things seem to have been made by Atari lately. Asteroids, BattleZone, Centipede and more recently a Crystal Castles. Well, what i had been doing for these is building up a damn great long loom that reached from the AR2 that was tucked away under the bench up to the top of the bench where it interfaced with the PCB through a pretty normal "jamma" adapter thing that enabled me to also connect it to my jamma test rig. There were a few things wrong with this though and after the first two looms it became VERY apparent i had to do something about it:

I was using yards and yards of cable - and this stuff ain't cheap contrary to what some people may think.
Each loom was taking 2 or 3 entire evenings to make up (i make them to last!!)
The power connectors Atari used are pretty pricey these days
Each loom was also using a jamma fingerboard and i only have a few of these left with no-one making the nice ones i like to use
Probably most importantly by connecting the whole thing up to my jamma rig i was creating a separate connection to a whole seperate ground through the PSU of the jamma rig. I've not really got a clue of the real world effect of this but in my mind it couldn't be a good thing!

Okay, as we can see a LOT of reasons to come up with something better, but what? After a lot of thinking about this i got a 10% off voucher from the place i normally order all my bits from and that kicked my arse into gear and off i went. Inspired by Mark's jamma adapters over at Leopardcats.com i trotted off and bought a nice black box and a bunch of other stuff and here's how it turned out. I'm pretty pleased.

inside

Looks pretty straightfoward?

Okay, let's dig into some detail.

This basically started off life as my BattleZone adapter and i chose to hack this one up as it used the most pins of the two i'd made up. The square connectors in the bottom left plug directly into my AR2. This means i could also take this with me anywhere someone has an AR2 and power brick, or even an Atari cab. The main voltages are fused. Call me picky but i figured bunging a few inline fuse holders in place and suffering a little voltage drop was a small price to pay for saving my (or someone else's for that matter) PCB if i slip with the meter or probe. Borrowed from the Atari loom is a two pin mate n lok connector which is used to bypass the right hand side of the AR2 and provide the 36V AC C/T direct from the PSU for those games that need it (Asteroids for example). It is this and the logic +5v that are fused. The three loose wires that you can see are the square 4 pin connector that handles the audio out frm the AR2. I can't find any of these in the UK only the rectangular ones so i just shove the pins in. Bit crude but it works.

Digging further, let's label it all up and quickly rattle round what we have...

explain

This is what i call the "Odd" power from the AR2. It's the 12 pin connector on the right hand side of the AR2 that handles the -5/+12/-22/+22v DC. Each of the first twelve pins on the D connector are connected straight to the corresponding pin on the AR2 end. Then, as we have a few left over on the 15way D connector, i've used two for the 36V AC C/T supply to come in and also some games have "Audio Rtn" in use and as the speaker is connected internally here we use the last spare pin on this connector for Audio Return. As this connector handles voltages each wire has heat shrink tubing on it's connection and all of the pins are rated to 7.5A power.
This is the standard logic voltages. A 9 way D connector with all the pins wired straight to the corresponding pin on the 9 way connector of the AR2 (or AR as the case may be). Again, these handle power so are all nicely heatshrinked and rated at 7.5A. No spare pins to play with here!
This one has a lot more going on. The top row handles all the connections for the controls that are embedded in the test unit. The first three power the LEDs in the start buttons (proper Atari ones) so they're heatshrinked. Virtually no current whatsoever but i figured why not.
The blue wires are basically all the switchgear in the lid. The usual fodder. Coin 1, Coin 2, Start 1, Start 2, Service, Test and finally the extra toggle switch is for those games that toggle the video via the harness such as Asteroids and Asteroids deluxe. It requires two wires.
The white wires would in the jamma world be considered the player 1 controls. I wasn't sure whether to include these or not since they only really pass straight through the box but i did as i already had a PS1 joypad hacked for my jamma rig so i made sure the connecter and pinout was the same so it will just plug straight in. Of course, in the Atari world these connections should just be considered as the first 7 (+ GND) control lines since they can, and certinaly will be used for things like spinners and trackballs in some games. Just more convenient to think of them as Up, Down, Left, Right, B1, B2 & B3.
As with the white wires the purple ones are simple control wires for P2 or more realisticly control wires 8 to 14. Use for whatever the games dictate and make up a controller to plug into the socket on the left accordingly. Note that these two connections are low power logic level connections and as such i've not bothered with anything more than fairly thin guage unshielded wire.
I chose to reduce the number of connectors i'd need by mounting a speaker in the unit and the volume pot as well. I think it works pretty nicely and also makes the whole thing nice and compact.
The Start 1 and Start 2 buttons. Proper Atari ones of the flashy light variety. In my opinion an essential and largely overlooked troubleshooting aid. I always used to add two LEDs to the edge connector of my looms for this job so it made sense to find some proper lit cones from somewhere and add them in.
Coin 1 and Coin 2 buttons. 'Nuff said.
Service, again, not much to say about this.
Test switch. I wanted one the same as on my jamma rig where you push it up and it stays up, thus mimicking the slide switch normally found in Atari games, or push it down and it is a momentary push that doesn't stay down like "normal" buttons. Sadly the only place i've got them from in the past was out of stock so this is just a normal toggle switch. It'll do for now, maybe later i'll get a proper one but it's unlikely now i'm finished!
The volume pot. Adjusts the volume - Duh! The original cabs (or at least my Asteroids cabaret) use a 50 Ohm pot. Presumably logarithmic. The only thing i could sensibly get hold of was a 10K log. pot. Hopefully it'll work fine.
This is the video invert switch mentioned before but of course it can be used for anything you may need it to be used for as long as you wire the two pins correctly in the plug in adapter you make up as it doesn't share a common ground with all the others.

Well, that's pretty much it. The idea is that i now just have to make up a relatively normal length loom (4 inches or so) with a bunch (up to three) of D plug's on the end and away we go. MUCH simpler, MUCH less time consuming and one hell of a lot neater :o)

Oh before anyone else spots the flaw in the plan, let me just say it's not a flaw. What about video i hear you say? Well, AHA! Everything but everything in this little unit is in it for a reason and that reason is to make my life easier and on the whole simpler and tidier. I thought about the video. I thought about having yet another D plug for input on the right hand side. At the end of the day though it would have just been another plug that went from one side to the other with the video device (XY monitor or Raster) just plugging in the other side of the unit. Seemed pretty damn pointless to me and would have just taken up another three connectors in the rig and meant one more connector to add to each loom i made.

Instead, i have a standard pinout for my monitors (both XY and Raster) anyway that i've been using for all my looms so i'll just continue to do that until i feel it's such a pain in the arse that i decide otherwise...
One final comment on the Atari rig. It didn't end up being a particularly cheap project. I'm sure i could have scrimped and saved here and there but i like to do things as properly and as nicely as possible. In the end the overall cost of this project including about 20 spare connectors of each size for looms (which should see me through a few years!) was rounghly £50. Eek!! Oh well, i guess if you're going to do something then you may as well do it properly

Oh, and all info and pictures are copyright me 2006 unless they're not - i don't really want to have to sit here and watermark the pictures so don't nick 'em and please if you want to link to the page then feel free but please link to the home page of my site here instead. Ta.