I'm not sure this really qualifies as a project, but it is useful information and a bit of a new product review.
Sadly, as things get older, they start to break down, ourselves included. Power supplies for the Commodore computers are no exception. One of the leading failures that people are seeing is the voltage on the 5 volt DC supply starts to creep up past 6 volts. Usually by this point you know something is wrong because the higher voltage has damaged you beloved Commodore VIC-20 or 64. So far, older VIC-20's that use the 9 volt AC appear not be affected, but the newer VIC's that use the same power connector as the 64 are at risk.
On my computer, the power supply was maintaining 5 volts, but could no longer supply enough amperage and the computer would just stop working and give a black screen if I restarted it. I fear this may have also been the last nail in the coffin for my SID chips as well, as they failed at the same time as the power supply.
If you would like a little more information on C= power supplies, c64-wiki.com has a good write up. If you would like to test your power supply, here is link to a pinout diagram.
Yes, an NA power supply works on a PAL C64. However, as far as I know, there are some stuff (i.e. GEOS) that uses the internal clock managed by the CIA. The challenge is this IC expects a 50Hz signal in a PAL Commodore to keep things in sync. I just wanted to make sure that if I have to get a new power supply, it will work for everything