Commodore 64: Upgrade to Heatsinks

I’ve written about my Commodore 64 from 1984 before. It’s a machine that I got from someone who had belonged to CSUN [Commodore System User Network]. He maintained it very well and had lots of floppies and manuals. I’ve had this for at least 10 years.

Over the past 10 years, I’ve done a number of things with this system. I got a EPYX 500XJ controller and refurbished that. I’ve gotten a good number of original C64 game cartridges.

I love it when old tech [C64 from 1984] and new tech [SD2IEC from 2021] can merge together.

Most recently, I even got an SD2IEC unit, so that I can access a MicroSD card with the Commodore 64. This is great, because I can use my Windows 10 machine to download D64 [Commodore 64 disk image file extension] files, put them on the MicroSD card, and then run them on the C64 from the card.

But there was something I did not know about until a few years ago, when I finally opened the machine up and took it apart.

The C64 had an issue where it would glitch out and reset for no reason. I noted that this would happen after the unit had been running for a while.

So I opened it up and noticed that it had an RF shield covering up the motherboard.

WHAT IS AN RF SHIELD?
The RF shield, or Radio Frequency shield, was a requirement by regulators to protect potential radio interference. Back in mid-80s, the radio frequencies emitted from the C64 could interfere with the operation of analog television sets.

That BIG metal cover is the RF shield. It also doubles as a heatsink.

I haven’t had an analog television set for close to 2 decades. And even though it has holes in it, the RF shield can still hold in the heat.


A QUANDARY
A while back, I took off the RF shield to see what was underneath it. I saw this:

Those white stains on the chips are the result of old, dried up thermal paste.

I saw this, and paid no mind to it at first. I had read that I could throw out the RF shield, so I removed it and gave things a try.

A few keys wouldn’t work properly, and the unit would shut down after a few minutes. So I did some more reading and learned about thermal paste [aka “thermal grease” or “heat grease”].

It seems that the RF shield works to double as a heatsink of sorts.

My original fix for this was to order more thermal paste, put some on it, and reinstall the RF shield. This worked, and I continued to use it this way for a few years.


MOVING TO A HEATSINK SOLUTION
Thermal paste is disgusting. It’s hard to get off of anything and everything. So getting it removed from the chips was quite the challenge. I constantly got it on my fingers. It’s truly messy.

Fresh install of new thermal paste. I had spread it too thinly. The BEST way to install thermal paste is to put ONE DOLLOP where the contact would be, and then allowing the contact to spread it evenly. This was an amateur mistake, and my reasoning for doing this was simply to cover where the old paste was. The dollop method ensures that no air bubbles wil exist in the thermal paste, which can allow overheating.

I had also used too much, and did it wrong. I did redo it a second time, using the dollop method, but still added too much in my quest to ensure that I added too little.

The second installment of thermal paste, using the dollop method. This is AFTER the heatsink/RF shield was installed and then removed. If you use thermal paste and remove the shield, it is recommended to REDO the thermal paste to avoid air bubbles.

I had to remove the thermal paste. Full removal allows the chip to have its natural appearance. However, it seemed to have stained some of the chips.

THE HEATSINKS
Heatsinks [or “heat sinks;” I’ve seen both spellings] are aftermarket pieces made of aluminum and are designed to wick heat away from computer chips.

With bigger modern computers, I’ve seen big heatsinks being installed on top of a big dollop of thermal paste. There is nothing wrong with this.

My beef with thermal paste is that it’s just way too messy, and it needs to be redone every so often. I wanted something cleaner that would last longer, hence the heatsink route.

These heatsinks come in a bag of 10 for about $8.50.
While some heatsinks work with thermal paste, these have thermal tape already installed for convenience.
At an angle: To the left is the “walled” area, and to the right you can see the open trough. Installation direction might not be an issue. For me, it was a matter of confirmity and consistency.

The surfaces of the chips had to be cleaned so that the thermal paste was removed. After that, the heatsinks could be installed. I did not have any special instructions on how to do it, so I positioned the heatsinks on the chips [2-3 per chip] so that the part that looks flat and walled was on the outside, and the parts that were opened and grooved were lined up.

The idea is to imagine the air flowing through these ridges.

Putting them on the chips was a little tricky, just because everything is so small. But I was able to get it done, and it looks WAY better than it did before.

I did not use any chip surface purifier. That, combined with teh flash, gives the chips a grey look. I don’t think that this will cause a problem.

It is important to note that the thermal tape on these heatsinks is VERY strong. Once you place them down, you can slide and move it a little bit. But before too long, it feels like the heatsink is permanently attached to the chip.


PERFORMANCE
I do not have anything to tell me the temperature inside the breadbox. All I have to go on is how the computer performs. This means watching out for the problems that it had back before I learned that I needed to redo the thermal paste, and hoping that nothing burns out.

This isn’t the most scientific approach, but it’s all I’ve got.

When this Commodore 64 overheats, there is a typing issue that occurs, where the T, Y, and I keys DO NOT register any keystrokes. So if this happens, you’ll know that it might be overheating. I learned the hard way, after disassembling the keyboard and putting it back together. Lots of tiny screws and some soldering involved in that.

I was able to write a long journal entry and save to 5-1/4″ floppy without incident.

I played Donkey Kong Jr. for about a half hour and got up to around 200,000 without a shut-down or any glitching. I then continued with a few more games and everything performed fine.


IN THE END
Nothing lasts forever. I’ll probably have to replace some chips, and I plan on replacing ALL of the capacitors sometime next year. Once I recap it, that should last me the rest of my life.

Retro computing has become a major hobby of mine. I was interested in machines like the Commodore 64 when they first came out, but I could not afford one back then.

Now that they’re affordable, using the Commodore 64 takes me back to long-gone time when life was simpler and having 64k of power meant that you could control the world.


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Published by DrumWild

Writing about drums, music, and philosophy.

One thought on “Commodore 64: Upgrade to Heatsinks

  1. A truly educational read. You have a way of explaining things that makes it painless for an ignoramus like me to understand. I’m still in awe over that ultra- detailed pic of the heat sink. Yup, I enjoy looking at things like that. Last but not least, your description of thermal paste reminds me a lot of my misadventures with super glue 😁

    Liked by 1 person

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