NTSC Video Issue After C64R MK2 is Powered On For Extended Time

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Don't Panic. Please wash hands.
  • I finally built my Reloaded MK2, and I'm having the same problem. After reading about this problem here and on other forums, and after some experimenting, it seems like the best solution is to just install a quiet fan inside the case. When I aim a fan at my case the problem goes away, and others have reported the same.

    I don't have the soldering skills or tools to solder that resistor, and I don't know where I'd find anyone to solder it for me. I can solder, but not something that small and delicate. And one person says that the resistor change caused problems with PAL mode, and I don't want that. The fan seems to solve the problem without creating any new ones, and it will also keep my old C64 chips a little cooler.

    So my question is, where is the best place to tap power for a 12v fan? I could maybe use a 5v fan if that's preferable, but I already have a quiet 12v fan.

    And is there any place on the MK2 board where I can safely drill two small holes to mount a 40mm fan on stand-offs? Ideally I'd like to mount the fan to the MK2 board on approximately 2-3cm stand offs so that it's raised up near the case vent to force air out of the case. I could maybe figure out some way to attach it to the case, but there's no obvious way to mount it, and it seems a lot better if it's mounted to the MK2 board so that I can easily swap the whole thing to a different case without having to remount the fan.

  • After looking at the board, it doesn't look like there's any reasonable place to drill holes that wouldn't hit traces. In future versions of the MK2, it might be a nice addition to the board to have a fan power connector and a place to mount a fan. It looks like a fan could be mounted in the middle of the board if it included 4 additional mounting holes.

  • Actually even if there's a place I could safely drill just one small hole in the MK2 board, that might be enough to mount a fan. I'd have one leg of the fan mounted to the board and the other 3 legs of the fan just resting on the board.

    Also I should say that I'm using a 64C case, not a breadbin.

  • I do not plan any changes to the C64RMK2 board - and I certainly do not recommend to drill any holes in it!

    There's quite a few mounting holes around the board that you can use. Either you use a small piece of sheet metal to mount the fan on, or you get a little more fancy and use a bolt with plastic-tapping male thread, and an inner M3 thread to lift the mounting position a bit.

  • I obviously would not drill holes in the board without you okaying it and specifying a location. I don't want to damage the board or void my warranty. None of the existing mounting holes are in a great location to mount a fan in the 64C case, but I'll figure out some way to make it work.

    Is the best place to tap 12v power at the power connector, or is there another location closer to the middle of the board?

  • Best place would be the switched 12V signal. Note that the 12V do not pass directly through the switch, but through a FET that gets a switch signal. Here's the highlighted trace:

    (click to enlarge)

  • Would it also be okay to power a fan from the same 5V connector as the LED? I realize there is a "blinking LED" error condition which maybe isn't ideal for a fan, but that shouldn't be happening under normal operation so I don't see it as an issue, assuming there is enough current.

    After initial tests with a 40mm fan inside the case, it seems to have completely solved the issue. My MK2 would fail consistently after about 45 minutes and the case would get warm to the touch in the top-middle. But the case no longer gets warm, and my MK2 has been running for more than 12 hours without issue.

  • Would it also be okay to power a fan from the same 5V connector as the LED?

    No - the amount of current you get there is rather low, as there's a resistor in the way.

    I'm aware that the C64 has lots of fans on the planet, but I wouldn't be surprised if you're the first to put a fan inside a C64 :-)

  • I'm aware that the C64 has lots of fans on the planet, but I wouldn't be surprised if you're the first to put a fan inside a C64 :-)

    :) It seems a little inauthentic to have a fan inside a C64, but I found that a 330 ohm resistor makes the fan completely inaudible and it still cools well enough to avoid the glitch. I'm also happy that it's keeping my SID and VIC chips a little cooler.

    Although I'm at least the second person to install a fan because I got this idea from somebody else who also solved the MK2 NTSC problem with an internal fan.

    I've now had it turned on continuously for more than 2 days with no glitch.

  • The last reply was more than 365 days ago, this thread is most likely obsolete. It is recommended to create a new thread instead.