These are posts related to hardware repairs and how they were fixed.
The video signals coming from the Commodore 64 have always been challenged by inherent ‘clock noise’ of the VIC-II graphics chip and the color bleeding of the S-video signal. The problems are easily recognized in the form of vertical lines (banding artifacts) or as a … Read more
This may come as a shock to some, but the sad news is that the old chips inside a Commodore 64 will eventually fail!! Most often the chips will simply die due to old age or other external factors like a faulty power supply. When … Read more
Repairing Commodore 1541 Diskette Drives (link) is not something I have tried before. But when I recently had these four broken drives thrown in my general direction I had to take up the challenge! The problem with diskette drive repair’s is that most diagnostick software … Read more
During the last couple of weeks I’ve received 8 (!) broken Commodore 64 machines that were in need of repair. The repair logs of three of them have already been described here (link), while the latter five had issues ranging from faulty Serial Ports (link, link, link), … Read more
I have fixed quite a few broken Commodore 64’s, but this one was by far the most challeging one! The machine started out as a simple memory fault that was fixed so it could run the cartridge game of Jupiter Lander. However, it took a … Read more
I just got this stack of broken and badly discolored Commodore 64C’s from a friend. The cases were made in China, Hong Kong and Germany… The first board is an Assy 250469 Rev. A board that had a broken keyboard – some of the keys … Read more
The most common cause of a black screen on the old Commodore 64 long boards (link) is a broken Programmed Logic Array (PLA) chip located at position U17. Based on different input signals, the PLA creates chip select signals and controls which chip is to … Read more
My quest for obtaining the last Commodore 64C motherboard version in my collection (Version B-3) has come to an end! I finally managed to get a copy of the Assy 250466 motherboard for a reasonable price. I got the machine from a guy in England on … Read more
Repairing broken Commodore 64’s is usually a matter of qualified guesswork and quite often substitution of chips is the only practical way to diagnose a fault. At least that is the approach I’m using when trying to resurrect broken machines. The challenge with this method is … Read more
A black screen Commodore 64C Version E short board (Assy no. 250469 Rev. 4) landed on my workbench a couple of days ago. Everything started out as a simple power switch replacement and memory IC swap, but ended up being a little more complicated than … Read more