The Geekorium

Stalled

In parts [one]({{< ref “restoration-of-a-childhood-icon” >}}) and [two]({{< ref “restoration-of-a-childhood-icon” >}}) of this small series I tried to repair my childhood Commodore 64.

I’ve tried a lot since my last post and completely botched it, so all-in-all I’m feeling pretty confident in myself and happy with my progress.

Testing, testing

Step one was to try the test cartridge when it arrived. Plugging it in I got a completely different unique garbage pattern, and a green border instead of the usual blue. This said to me that parts of the test cartridge were working, but that something NOT tested by the cart was to blame for the garbled pattern. A bit of research suggested the logic chip can sometimes output this sort of nonsense, although I was unable to find any pictures showing either of the issues I’ve experienced. I ordered a new 74LS373 logic chip and a backup 8500 CPU just in case, and sat quietly in the corner of the room for them to arrive.

I’m not equipped for this

The new chips arrived - and as the CPU I have is socketed - it was a quick job to see if the new 8500 would help. It did not. The logic chip was not socketed, and so I made a trip to Jaycar for one so I could start the process of making the whole board more easy to use for testing chips.

I did not spend the money on a desoldering gun, and soon regretted it. I was not enjoying it, but I was at least making progress until the final pin of the old logic chip didn’t de-solder the whole way and pulled up the trace on the board all the way back to the previous thru-hole.

I tracked back to Jaycar and purchased some silver trace paint and some wire. The trace paint was a waste of time (although I could have been doing it wrong), so I’m glad I picked up some wire while I was there. Then I installed the socket and tried to hard-wire the pin on the broken trace back to where it needed to be.

One, Two, Three

My attempts had made things worse. With the new logic chip in place in the socket and my gross wiring, the display now cuts in and out. Mostly out. The crazy patterns are still there too, making it clear the logic chip was not the culprit so I also shoddily removed a potentially working logic chip. Finally, I thought it might have simply been a dodgy soldering job, so I rechecked my work, and in the process learned my soldering iron might be too hot for this sort of work, and I’ve melted parts of the socket and I’m worried I’ve damaged the PCB even further.

Time to give up

At this point I was ready to pack it in. Deep down I’m not ready to stop, but I reached the limits of my knowledge about three steps ago, and have little to show for it. I reached out to friends who gave me some further advice, but I thought I’d sit on if for a while and try to decide the next best steps.

Fortunately I may have some better news for the next post in this series.

40-Year-Old Computers Are A Nightmare

Restoring my childhood computer is apparently going to take longer than I hoped. [Restoration of a Childhood Icon Part One]({{< ref “restoration-of-a-childhood-icon” >}}) ended on a bit of a bummer, and (spoiler warning) this part is also not the conclusion I’m looking for.

On Mike, First of His Name’s advice, I ended up purchasing a set of new capacitors and a modern PLA replacement chip from Retroleum.co.uk, then waited patiently for them to arrive.

Like Riding A Bike

In preparation, I’d asked for a soldering iron for my birthday, and also grabbed myself some supplies so I could dredge my rusty soldering skills out of their 30 year hiatus.

With solder in hand, and solder sucker in… also… hand, I started by recapping the board. Fortunately, once you learn to solder it’s not difficult enough to forget, so I soon had new capacitors in place.

However on testing, the old boy still wouldn’t give me anything better than a black screen.

Light At The End

But fear not! I had the replacement PLA chip! And with this baby in place, I was…

Only slightly better off.

On testing, I’m getting somewhere with this new PLA, but it’s clear that the PLA was one of the issues with the old boy, but not the only one. Now instead of a black screen, I get the familiar blue border indicating not everything is borked, but I get a jumble of colours instead of the expected BASIC intro text.

At this point Mike offered to take the board and run some tests and repair it himself, but I’ve come so far and want to see the repairs through myself if at all possible. So on his recommendation, I’ve ordered myself this diagnostic and dead test cartridge to see if I can suss which chips are still not quite right.

The Pictorial C64 Fault Guide doesn’t show any issues quite like mine, so I need to do some digging of my own.

So stay tuned for part three, when I wire up my test harness and try and pry some chips.

The Pull of Nostalgia

Ever since [sending my old Commodore 128 to a better place]({{< ref “c128-journey” >}}), I’ve been thinking of it’s older breadbin C64 brother I’ve got sitting in storage. I knew we mostly used the 128 because the 64 stopped working, but I couldn’t remember exactly what was wrong with it. Thinking it was completely dead, I felt like even just putting the shell to good use would be a win. There’s some great tutorials and components you can buy that can help you convert a non-functional Commodore 64 into a modern PC or USB keyboard.

However, after almost 2 years of thinking about it, I decided I didn’t want to gut the thing until I was really sure it was dead. My mum has one of those C64 Minis and what I discovered getting that running was that emulating the Commodore wasn’t the experience I wanted to capture (or recapture). The C64 full size upgrade appears to be a better experience, but is completely sold out everywhere.

I have this small piece of my own history sitting in a cupboard, and I’ve decided I wanted to try and do what I can to breath new life into it.

Problem One: Power Supply

Step number one was the power supply. Conventional wisdom is that you don’t ever, for any reason, do anything to anyone for any reason ever, no matter what, no matter where, or who, or who you are with, or where you are going, or where you’ve been… ever, for any reason whatsoever… plug an original Commodore 64 power supply into a Commodore 64.

The problem as I understand it, is that the 5V DC line on the power supply will eventually inevitably break and pump more voltage into the machine than its chips can handle. There’s also a 9V AC line that’s far more stable and doesn’t cause issues, but that DC line has killed more Commodores than time alone would be responsible for. So before I could see if the machine even worked, I would have to get myself an alternative modern power supply. There’s a couple out there, but I’m told the most reliable modern PSU is the C64PSU made in Poland. Getting a PSU shipped from Poland seemed like an expensive way to start however, as there could be many more things wrong with the board, and having a working PSU sitting around with the broken computer seemed like a waste.

Then, the astonishingly generous Mike, First of His Name¹ from https://chinwag.org offered to send me his C64PSU as a loner from his lockdown in Melbourne, kicking off my attempts to finally get this thing repaired.

Problem Step Two: Spring Cleaning

While I waited for that to arrive, I gave the whole thing a spruce up. The case got a clean in the dishwasher along with the keycaps, while the board got a brush down with a soft brush. The internals don’t look too bad, and I can’t see any capacitor bulges with the naked eye.

I’m happy with how it turned out, and I’m even oddly proud of the couple of melt-marks on its upper grill. In my research I learned that the marks are quite common on these machines, and weren’t caused by some sort of over-heated wire or soldering iron (as I’d originally presumed) but due to a chemical reaction between the plastic of the case and something in the cables a lot of people wrapped around their C=64s while they were in storage!

Step Three: Tuning Up

Finally the other night I was able to pull out my old CRT TV and plug in Mike’s power supply and see if the thing would even boot any more. The LED came on - which was a good sign, as I vaguely recall previously attempting to get it working and not even getting a light (leaving me fearing I’d pre-fried my chips!).

The CRT is the only TV in the house I still know how to tune via RF, as I’ve also since remembered that we never once had a proper AV cable for the Commodore, and always relied on tuning the TV to channel 3 and plugging direct to the RF port (prompting memories of swapping cables at the back of the TV any time we wanted to play games).

Problem Four: Nothing

Tuning the RF was successful after I worked out how to tune the TV with the sparse controls, but alas - I only have an empty black screen. As setbacks go, this is quite a big one - more research shows the completely black screen can be commonly caused by upwards of a dozen different issues, and tracing it to the real issue is going to take time… and money.

{{< video5 webm=“//turbo.geekorium.au/video/C%3D64/C%3D64-power-but-black-screen.webm“ mp4=“//turbo.geekorium.au/video/C%3D64/C%3D64-power-but-black-screen.mp4“ vtt_en=“https://turbo.geekorium.au/video/C%3D64/C%3D64-power-but-black-screen.vtt” >}}

Speaking to Mike we think the next step will be to replace all the capacitors on the board and see if it makes a difference, followed by replacing the PLA². After that your guess is as good as mine. Some very clever people have dozens of tricks to determine the myriad ways a C=64 can be busted, and I’m hoping to learn a lot as I figure this out, but it may be slow going and I might not have anything to show for it for a long time, if ever.

And that’s where I’m leaving it for now. I’m looking forward to doing this, and trying to keep the cost to a minimum as I go. Getting the old thing cleaned up really confirmed my desire to get it working again. Wish me (and the memory of the 5-year-old I used to be) luck!

It’s 9:30, so class just finished, but I left at 8. Another night of confusing information that would probably make sense if I’d read the text before hand, or wasn’t being taught by someone who’s thinking of examples on the fly and can’t finish a sentence before moving on to another concept.

I’m gonna just sit down tomorrow and current text be damned, read a whole bunch of chapters and just work on the half assed examples in the text I have. Hopefully that will keep me going. I can’t keep putting it off.

My next chapter is Methods, so hopefully that might answer some of my questions about when to use methods and how.

When I was 13 I was around at my mate’s place as often as I could be just to play Wolfenstein 3D on his better-than-mine system. He had colour graphics and a sound card, while my Commodore 64 only had enough grunt for side-scrolling platformers and breakout clones¹ and my IBM clone could barely muster monochrome. Wolfenstein was the pinnacle of gaming. It was just like you were there, with your little gun waving in front of you and meals left on the floor. And B.J. Blazkowicz’s face peering out at you to remind you to keep away from big men with chain-guns. I couldn’t play it enough.

Seriously. Couldn’t play it nearly as much as I wanted. My mate wanted to play too, and I couldn’t really stay there all the time playing his computer. Multiplayer was not invented for 3D shooters until Goldeneye,² so I had precious little time to play it. Add four strict Christian parents hovering around and I never got to play more than a few levels.

I still remember clicking space at every wall panel to try and find the secrets on the precious few levels I played. Remember the glee at finding a new gun levels before you we due to find it just lying around in the course of the game later on.

Every first-person shooter to come since has built on wolf3d.exe - adding a bobbing gun, smarter bad guys, and polygons, but they’re all trying to capture the same sense of joy 13 year-olds got playing this game for the first time. Knowing instinctively that this was the beginning of something monumentally fun. For me, every first-person shooter since has been just as frustratingly out-of-reach for me too. I’ve never had the hardware required to play the groundbreaking games that have been released.

But not today. Today I have Wolfenstein 3D on my iPhone. Lovingly re-crafted by the man who made it the first time round. Full of the same bad-guys, the same weapons and the same secrets. I have in my pocket something I couldn’t run on the machine on my dad’s desk. It’s my proudest purchase, and one of my fastest.³

Wolfenstein 3D Classic (App store link) [hat-tip to oliyoung]

I loved my old Commodore 64. It had fantastically playable games, neat 16 colour graphics, and that awesome SID chip for the charmingly wonky C=64 sound. You could program on it, play on it, wait for things to load on it…

It had cartridges, it had a tape drive, it had a clunky disk drive that worked marginally faster than the tape drive. Really, it was shit compared to what we have today, but man-oh-man it still outstrips every one of the computers any true geek has ever owned since.

On Monday, the Computer History Museum in Mountain View, California, will celebrate the C64’s 25th anniversary. CNN article on Commodore 64 anniversary

In August 2007, the Commodore 64 made it to 25 years old. And in honour of the Computer History Museum’s celebrations, I have created a Commodore 64 Wordpress theme to add to my website. If you’ve come to this page wondering why my site is all big and blue and chunky - it’s to pay respect to a truly wonderful computer.

If you’ve come here looking to get the theme yourself - let me know and I’ll see if I can make it available to download. It’s still a work-in-progress, so expect to see some changes before things finally settle and I haven’t tested it on any versions of IE. It’s a little harder to navigate, so I’ve made a menu link up there in the top right corner, so you don’t get completely lost.

I’ve made the comment areas blue too, so you can relive the joys of typing LOAD “*”,8,1 yourself, so go on and leave me a comment. And everyone, please be patient for the next two weeks and join me in remembering one of the best computers I’ve ever owned.

LOAD “*”,8,1