The VIC-II and SID chips in the C64/128 are prone to over-heating and are rather expensive to replace nowadays. Some other ICs in these machines may have the same issue.

An unmodified machine includes a large metal RF shield which usually performs the duty of being a heat sink for VIC-II, SID, and other chips. However, the RF shield is frequently missing from machines that have been damaged, worked on, modified, refurbished, etc. Therefore, that heat sink is also gone. I also question whether it was ever a very good heat sink to begin with, or just another way for Commodore to control costs.

What is a reliable modern replacement for the original RF shield's heat dissipation function? Which chips in the C64 and C128 should have such a heat sink installed?


Modern heat sinks

I assume this is about heat spreaders, as that is what they do.

What is a reliable modern replacement

Any one available at the usual stores will do it

Which chips in the C64 and C128 should have such a heat sink installed?

All may benefit, as they are NMOS and thus heating.


It's about the surface size - larger surface to radiate the heat results in cooler chip temperature. In reality a plate with fins placed in the middle of an IC will get the most. Already a small one does make a noticeable difference.

The metal used should provide a good thermal conduction like:

  • Diamond (1000 Watt per Meter per Kelvin))
  • Copper (400)
  • Aluminium (250)
  • Iron (100)

As it's about getting the heat from chips to radiating fins.

A darkened surface increases radiation. Although the darkening matter should as thin as possible - at least between chip and carrier, as it's an additional barrier reducing thermal transfer.


Anything surface temperature (without heat spreader) less than 20 degree above environment is not worth the effort.


Dig thru your parts box and see if you can find some old 386 / 486 / chipset heat spreaders with fan. They are still small enough to fit inside a C64 and will get everything way down.

Similar modern RAM heat spreaders can be used across several chips (like the RAM)

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