The article states, "The device labelled as C55 (or C48 for cost reduced board) is a fine tuning adjustment for the TTL clock driving the 6560 chip and should not be altered." I have found that this is exactly what needs to be altered in order to fix colors that are slightly off. Some VIC-20's boot up with a green border instead of cyan. Fine tuning the frequency will correct this. For some VIC's the variable capacitor (C55 or C48) must be adjusted with a non-conductive alignment tool. Using a metal tool, like a jewelers screwdriver, will often interfere with the color signal making it impossible to see the colors while adjusting. It would probably be a good idea to use some form of thread lock (Loctite) to paint on once it has been properly adjusted.