During the 2000's into the 2010's I had 2 Control-24's in my studios. They needed a lot of constant service to keep running. The first thing I did was to replace the standard Molex crimp terminals with the upgraded Molex crimp terminals that contact on 3 sides, I believe they were called "Molex D-Flex" or something. I may still have some in the bin if anyone needs me to look up the exact name. This was on all of the power and ground distribution harnesses. This alone fixed the "faders stuck on +6dB" and "flashing LEDs" scenarios most of the time. Then there was a capacitor in the PSU that was too close to a heat sink, and it would dry out every 3 years. I believe it was C11. The solution was to mount that capacitor on the bottom of the board, away from the heat sink. At the time I had detailed notes about all the different procedures to keep these boards running, but I trashed them when I sold the last console. Clients would regularly spill coffee and soda in the faders, luckily the faders were easy to take apart and clean. Usually I could restore the faders 100%, but sometimes I had to replace them with new faders, which were readily available for about $30 apiece. I'm really glad those consoles are out of my life!