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Atari 5200 Graphics Glitch Fix - “Tech Tip 7” From 1983


The Atari 5200 is an underrated console, in my humble opinion. But this one does have an annoying fault relating to a bad batch of CPUs. So let’s fix it using an official Atari-sanctioned fix from 1983!


Hey everyone, Rees here and welcome back to ctrl-alt-rees. In this video I’m going to be looking at my Atari 5200 and rectifying a known fault using an official Atari-sanctioned fix from back in the day.

This is one of my favourite consoles in my collection, and wasn’t even released here in the UK, and in fact was only on sale for just over a year back in 1982 in its home country of the US, so they’re pretty rare and sadly have something of a bad rap thanks to the much maligned controllers. But I think it’s actually a great console worthy of some love, and this one just happens to have an annoying fault - so lets get that fixed.

So if you were watching my latest livestream you’ll no doubt have noticed that I was struggling a bit with some weird graphical glitches, which oddly enough only seemed to crop up in a few games - most notably Pac-Man and Missile Command.

Sadly a reboot didn’t seem to fix it, and following through some helpful suggestions in the chat I ran through some diagnostics which seemed to show that the GTIA - the 5200’s graphics chip - and the RAM were perfectly fine. That’s right - anything can happen on my livestreams, and I even threatened to get the soldering iron out at one point.

So all in all, a bit of a mystery. Especially as other games like Pole Position and Robotron were working perfectly fine.

After the stream, I added the 5200 to the ever-growing repair pile, and it was only in the days afterwards I spotted that I’d received a message from Andy - AKA marauder666 - over on the AtariAge forums. Turns out that he caught the stream and had actually come across this issue before - and it’s a known fault with some models of 5200 that Atari even issued an official fix for back in 1983 - known as Tech Tip number 7.

These tips were originally issued to Atari service engineers in these chunky service manuals - something I’d dearly love for the collection but always seem to go for silly money when they do come up for sale. Thankfully of course they’ve all been scanned and are all available online, and it’s actually a pretty simple fix.

This relates to, supposedly, a bad batch of Rockwell 6502 CPUs - now, Atari being Atari of course, rather than replace the bad CPUs, which does indeed fix this issue, decided to come up with a much cheaper fix that involved adding a resistor capacitor network to drag that pesky CPU’s faulty timing kicking and screaming back into spec.

So I thought it would be fun to try it out.

So first up we need to dismantle the 5200 of course, and we need to remove the motherboard to get to the underside. Thankfully I have a big desk.

Just as an aside, I have an Ultimate Atari Video mod in this console, and it was one of the things I initially suspected might be causing the issue, despite having them in most of my Atari consoles and having never had any problems with them in the past. It’s great to know that this isn’t the cause of the fault and that I can happily carry on recommending and fitting them, as it really is a fantastic way to breathe new life into these old consoles by adding very high quality composite and s-video outputs.

Turning our attention to the CPU, it seems this is indeed a Rockwell with one of the offending date codes - as per the Tech Tip, it’s stamped with the letters RC and has a code higher than 8250 - in this case 8252, so I’m confident that this fix will work in our case.

Incidentally, week 50 would be Christmas week, and 52 new year. So I can only assume that those Rockwell engineers had had one too many Christmas tipples when they put these together.

Anyway, thankfully the wires that I previously installed for the UAV mod are plenty long enough that I can flip this board over to access the underside without disconnecting everything. Then it’s just a case of adding a 470 ohm resistor and 100pF capacitor as per the instructions.

The manual mentions standard testing procedures as outlined in the service manual, but to be honest, I think firing up a few games is more than sufficient in my case.

I may as well fire up Pole Position first, as although that wasn’t one of the afflicted games, it’s important to see that we haven’t made matters worse. Also, going back to Andy’s message, he points out that the colours looked a bit off, meaning that the colour pot probably needs a tweak, so I’ll also fix that while we’re here.

So lets revisit that first game where this fault reared its ugly head - Pac-Man. And as we can see, it’s all looking great! It’s a shame this game is pretty much unplayable with these controllers, but that’s something I’ll be addressing in a video very soon, so perhaps consider subscribing if you haven’t already so you don’t miss that one.

The next game - and one that got particularly horrific a couple of stages in - was Missile Command. Now this is a real gem on the 5200 and works well with these analog controllers as well as the optional trackball controller, so it’s great to have it working properly and playable again.

I’d call that a success, so lets put this console back together ready for many more years of error-free gaming to come.

So there we have it, such a simple fix for a very annoying problem and big thanks to Andy of course for the tip off. Now, I have some interesting projects coming up with this console including looking at and attempting to dump the contents of this very rare prototype Pac-Man cartridge which should be a lot of fun, and you may not know this, but I also covered an upgrade for these pesky controllers back in the early days of my channel, so I’ll link to that video at the end and down in the description.

If you enjoyed this video please consider giving it a thumbs up as it helps me out a lot with the channel, big thanks to my Patrons and channel members whose names you see on screen as I speak, and of course please do feel free to share your thoughts and experiences down in the comments as always.

So all that’s left is for me to say thanks for watching, and I’ll see you again next time.

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Relevant Links:
AtariAge Thread With “Tech Tip” Download:
Atari 5200 Controller Repair / Upgrade Video:

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