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A Curious Atari Video Game Machine Restoration


Restoring and composite modding a classic Atari C-100 Pong, Atari C-380 Video Pinball and an Atari SC-450 Stunt Cycle in preparation for a big book launch event. Can I save these classic consoles in time for the big day? Tune in and find out!


Just over a year ago I was contacted by legendary British game journalist Lewis Packwood - this incredible looking chap right here - asking for some help with a book that he was writing all about weird and obscure gaming machines - machines like these. Of course, as a collector and restorer of weird and wonderful Atari things, I was more than happy to help out.

What I didn’t consider at the time was that I’d be showing them off at the launch event, and even be involved in Lewis’s unique interactive talk all about the book.

But first I had some work to do - after all, it would be nice if people could see these up and running and even have a play with them themselves if possible - but most of them were still in my TODO pile awaiting some work. So I spent some time over the past couple of weeks getting them all up to scratch - or at least attempting to, as you’ll see.

First up, Atari’s original home Pong from 1975. Now, unlike the other machines here I have previously modded this one for composite video output, as demonstrated in a video with Neil from RMC a couple of years back - remember that one?

But I never sorted out a UK power supply for it - and although it was also designed to run on batteries, I wanted to have this up and running all day for people to play with - so now’s as good a time as any.

Hooking up the original US wall wart to my stepdown transformer, I can see that it’s outputting 6V. I mean, it also says that on it, but it’s always best to confirm. So I sourced some 6V supplies, but I could only get them with barrel jack connectors and the Pong uses an unusual 3.5mm TRS connector similar to a headphone plug.

And yes - this is indeed the same connector as the Atari VCS and later 2600 consoles - but crucially, the Pong machines need 6V while the 2600 and - more importantly - a couple of the other machines I’m using in the demo - is 9V - so it’s very important to bear in mind and I will be clearly labelling the machines to prevent any mixups.

So I sourced some barrel jack to 3.5mm adapters - job done! Well, except when I tested the polarity I realised that they were negative tip.

I’m glad I did that before I plugged one in and potentially damaged one of these rare old devices…

After pondering for a minute and considering my options, I decided the best course of action would be to reverse the polarity of the adapters rather than, say, grafting the 3.5mm connectors on to the 6V supplies.

By the way, I’m doing 3 of these because - well - that’s how many Pong machines I have, although I’m pretty sure one is beyond repair due to battery leakage and the other is pretty low priority for this talk as it doesn’t offer much over and above the original that I’ve already modded.

So after swapping the wires around, soldering and heat shrinking the adapters, we can see that we now have the correct polarity and voltage and a quick test confirms that everything powers up OK. That’s one job done!

I’m really glad I didn’t leave all of this to the last minute like I always do.

Yeah, no, that’s exactly what I did.

Now, another thing mentioned in the book is Atari’s Video Pinball from 1977 and I could tell from those early chats with Lewis that he’s a big fan of this machine and was really keen to cover this, not least because it also features an excellent home version of Breakout, which was a huge hit in the arcades at the time and of course was originally developed by Apple co-founder Steve Wozniak - who was famously screwed over and swindled out of a bonus by his business partner Steve Jobs during the whole process. But that’s a story for another time and either way none of their work actually ended up in this console.

The Video Pinball was under development at the same time as the original Atari VCS and indeed shares very similar video circuitry, including the RF modulator. I’m never going to be hooking this up to anything with an NTSC TV tuner and the ancient modulator is a potential source of RF noise, so I decided to remove it and as always store it safely away just in case I ever want to put the Video Pinball back to its stock configuration.

The modulator is attached to a large ground plane that acts as a heatsink, so in addition to the trusty moo gun, I also use the soldering iron to add a bit of extra heat and it all comes apart quite easily.

But before we can go any further, this board is pretty nasty to handle - as you’ve probably spotted, it’s covered in old flux and it’s quite sticky to the touch, which I’ve discovered is quite common with this old Atari stuff. Unfortunately I don’t have an ultrasonic cleaner just yet, so it’s time for some IPA and some good old fashioned elbow grease, including the bamboo toothbrush - an indispensable part of any electronics toolkit.

So, with that cleaned up, what will I be replacing that RF modulator with? Well, a few years back I bought some of these THS7314 analog video amplifier chips. This is a tiny surface mount component, but the ones I acquired are pre-mounted onto these really handy breakout boards.

These feature 3 channels and so they’re commonly used for RGB mods for things like the Nintendo 64 and the Neo Geo. But in our case we’re only dealing with one channel - composite video - which makes things a bit easier to hook up and the chip will handle this just fine.

Incidentally, I always refer to this RetroRGB guide when I’m working with them - Bob’s put together a really great page explaining what the chip is all about and how to get one connected up.

These RF modulators are quite well documented online already, but as always I like to test these things and just confirm the pinout for myself. We can work out our 5V and ground very easily using a multimeter, so by process of elimination the third pin must be our video signal.

The next step is to get a ribbon cable soldered in, and I’ll also glue it to the board for some strain relief. Solder isn’t supposed to be a mechanical connection after all and the joints can break if they’re pulled around too much, so it seems like a sensible precaution even if a certain subset of the internet gets angry about this stuff.

But hey, it’s all good for engagement.

RetroRGB’s guide suggests that a 0.1uF filter capacitor across the power pins is a good idea to eliminate noisy power issues, and who am I to argue?

Although I will say that it might be more accurate to describe it as a decoupling capacitor in this configuration.

So, with that wired up according to the guide, lets move our attention to the next machine.

Also dating back to 1977 and being based on a best selling arcade game, Atari’s Stunt Cycle is an even more rare and interesting device, and another one that Lewis was keen to cover in the book. A product of the Evel Knievel craze starting in the late 60s and spanning well into the 70s, Stunt Cycle has the player jumping 32 buses in their living room - as proudly advertised on the box - as well as a few other game modes that I and I’m sure others at the book launch were keen to explore.

Being a product of the same era and indeed development process as its sibling console the Video Pinball, Stunt Cycle also features the same RF modulator and therefore will be exactly the same composite video output mod. So that makes my life much easier.

The process is much the same - removing the modulator, cleaning off some excess flux (although it’s nowhere near as bad this time) and adding the wires to hook up the THS3714 video amplifier chip.

So let’s get those installed. As mentioned a moment ago, I’m only using one channel on these and the eagle eyed among you will have no doubt spotted that I’m using a 75Ω resistor on the output side as per the RetroRGB guide. We’ll see how the resulting signal looks and potentially tweak it by adding a resistor on the input side later on, but this should give us a picture for now.

After sticking the boards down with some self adhesive double sided foam pads to keep everything tidy, that’s the video side of both consoles almost ready to go, with the wires tucked neatly underneath.

As mentioned at the beginning of the video, these consoles originally used an RF signal, delivered over a cable like this one. It would be plugged into a TV and need to be tuned in as per any other TV station, and this isn’t the optimal way of hooking things up in this day and age, particularly as I’m on the other side of the pond.

So I’ll be using this - the trusty old composite video cable. I’ll run it out through the original opening so no holes to drill - see, I’m learning! - and as we also have audio hookups here, I’ll wire those in parallel with the original internal speaker so we can also get audio through the TV if required. It would be cool to wire up some kind of hidden switch to switch between internal and external audio at some point in future I suppose, but this will do for our purposes for now.

So after hooking all of the ground wires up to one of the original modulator grounding points - which I somehow didn’t record - and working out the polarity of the speaker connectors using a multimeter and hooking that up correctly, the final piece of the puzzle is the video output, where the yellow connector of the cable is soldered to the 75Ω output resistor on the THS3714.

…and here’s what it looks like all connected up and ready to go.

Now, I gave the Video Pinball a quick test off camera and it seemed to be working fine, so after putting it all back together I decided to put it through its paces and try out the various game modes, and it was here where I noticed a problem.

That awesome Breakout mode I mentioned was missing something - the sound seemed to be working and I could start a game which would launch a ball, but there was no paddle at the bottom of the screen - which is kind of essential to the whole process. So I had to strip the whole thing down again. I should have tested it more thoroughly.

Thankfully it turned out to be an easy fix - there are two socketed chips on the board, one which handles pretty much everything, and a smaller logic chip that does - I dunno, I don’t suppose it’s really important to this story. So I gave the legs and the chip sockets a thorough cleaning with some contact cleaner and a quick test without fully assembling it this time confirms that our paddle is back and everything’s working great!

So that’s that all back together - again - and we can turn our attention to the Stunt Cycle.

Well, this one’s not so good. There’s this weird rolling picture thing going on which looks to be some kind of timing issue. Tweaking the trimmer doesn’t fix the problem and neither did anything else I tried - including swapping out the one and only electrolytic capacitor. I was convinced that this was a problem with the crystal oscillator, and hooking it up to the oscilloscope only confirmed what I suspected all along - that I don’t really understand oscilloscopes.

I also had some compatible 5V regulators in my parts pile and had thought I’d seen the voltage being a bit unstable in my previous testing, so with nothing to lose I swapped that out too, but sadly to no avail.

So the Stunt Cycle ended up being a static display. It’s a shame but hey - 3 out of 4 devices certainly isn’t bad and the whole talk went down an absolute storm, including the big unveiling of the legendary Atari Video Music, the world’s first music visualiser and Atari’s one and only foray into the hi-fi market, which certainly attracted a lot of interest on the day.

Another big hit was the original 1975 Pong console, which was an absolute trooper and kept people entertained for a solid 6 hours - the cool thing being that, with the event being hosted at Retro Collective down in Gloucestershire, people could also pop downstairs to the Arcade Archive and see how it compared to the original arcade game.

Unfortunately the Video Pinball didn’t prove to be quite so sturdy and on the day it developed a bit of a dodgy power socket, so we disconnected it to prevent any damage. Not really unexpected for 45 year old technology and those 3.5mm connectors can be pretty flaky at the best of times, so hopefully that will be an easy fix. I would have grabbed a soldering iron on the day but hey, we were all having so much fun with everything else that before I knew it the day was over and it was time to pack up.

So overall the book launch was a big success, and as always with this old stuff, I have a couple of things to fix. I’m planning to have a look at those in a future video so don’t forget to subscribe to the channel so you don’t miss that, big thanks as always to everyone who’s supported the channel over the course of this year, and you’ll find lots of useful links down below to everything mentioned in this video, including a link to buy the Curious Video Game Machines book.

Finally, if you’re looking for something else to watch, you can check out my Atari Video Music restoration and history video which should be appearing on screen as I speak.

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