Today I was modding an Atari 2600 from PAL-M back to NTSC, a process that consists in removing a small transcoder PCB, restoring cut traces, removing added jumpers and replacing the system's crystal.
After doing everything but replacing the crystal, I turned the console on to make sure everything was OK. It worked fine, the colors were messed up, as expected because of the wrong crystal, but there were colors. After replacing the crystal, the colors were gone. The image was black and white, although there were visible patterns in areas that were supposed to be flat.
Then I found another crystal, with the exact same frequency written on it (3.579545), but in a different kind of packaging (the first one looked like this, and the second one like this), and it worked great. All colors were perfect.
Of course I'm glad it worked out in the end, but I would reeeeeally like to understand what the hell happened. The first crystal couldn't have been defective, otherwise the console wouldn't work at all. I also don't think the manufacturer would have written the wrong frequency on it. Could this be a polarity issue, and I got it right the second time by accident? Does the polarity matter for crystals in game consoles? Please hardware gurus, help me understand what happened!
After doing everything but replacing the crystal, I turned the console on to make sure everything was OK. It worked fine, the colors were messed up, as expected because of the wrong crystal, but there were colors. After replacing the crystal, the colors were gone. The image was black and white, although there were visible patterns in areas that were supposed to be flat.
Then I found another crystal, with the exact same frequency written on it (3.579545), but in a different kind of packaging (the first one looked like this, and the second one like this), and it worked great. All colors were perfect.
Of course I'm glad it worked out in the end, but I would reeeeeally like to understand what the hell happened. The first crystal couldn't have been defective, otherwise the console wouldn't work at all. I also don't think the manufacturer would have written the wrong frequency on it. Could this be a polarity issue, and I got it right the second time by accident? Does the polarity matter for crystals in game consoles? Please hardware gurus, help me understand what happened!