A blog of calculators, old electronics, and maybe other stuff too.
06 August 2019
Commodore 128 Part 3: RF Modulator Issues
When I first booted up the Commodore 128 and saw that it was working just fine, I figured the restoration would be a fairly simple task. The computer was dirty and yellowed, so some scrubbing and retr0brighting would be enough. Or so I thought.
Inside were some rusted components, so those had to be removed and de-rusted. I soaked them in vinegar for a few hours, then scrubbed them with abrasive pads. This worked really well, but I wanted to prevent future rust, so I gave them a black spray paint treatment.
Reattaching the cartridge cover was no problem, but unfortunately the RF modulator was damaged during removal and I didn't realize it until I started putting things back together.
If you look at the right side, you can see that the traces look really bad. I could not solder the pins back in place because there was nothing for the solder to stick to. At first I didn't think this would be much of a problem because I rarely ever use RF out, but unfortunately the RF modulator is required to get any video out from a Commodore 128. Without it, all I see is a black screen when the machine is turned on.
I researched replacement solutions for the RF modulator and found a DIY solution. The above picture is the result. It didn't work. This particular solution is for a Commodore 64, but the 128 has some slight differences. Frustrated, I had to order more electrical components to build another RF modulator replacement. It could be a few months before I get everything I need because I was only willing to buy the cheapest possible parts. Many of them come from China.
Damaging the RF modulator was an unfortunate mistake, but I was very concerned with the amount of rust that had formed on it. Removing it was vital to keep this computer alive, but until I have a replacement, this computer won't be doing much of anything.