You've basically got three problems instead of the usual one that American have with white PCEs.
1) You have a 220v power supply: This means the system probably either came from Hong Kong or Europe. Radio Shack can fix this problem. Get the PS with the highest amperage rating possible with the voltage you need. If it is a 9V system, get the 273-1771. Its like $25 I think.
2) You have a PAL converted unit: This...is pretty much going to screw you. You will need something that accepts PAL, and in the US that's amazing rare outside of a few high end TVs (and then only by enabling a service mode usually). You might find a TV card for your computer that will accept it. I have no idea how extensive these conversions are. That is, will they only convert the RF output to PAL, or does it also apply to the composite (unusable without a CDROM2 system, AV booster, etc) and RGB (unusable without a hack)? Maybe you can un-install the PAL conversion. If you can, then that brings us to the usual problem with RF only consoles from Japan...
3) The channels are different: Even with a straight up Japanese NTSC white PCE, you still may have problems tuning it in via the RF. I think channel 98, or 99 sometimes works. The usual 3 and 4 do not.
So yeah, good luck with this one.
If you can verify that the composite output (which comes from the expansion bus on the back) in unefected by the mod, then you can use an AV booster, or CDROM2 to work around problem #'s 2 and 3. Radio Shack will fix Problem #1 If the PAl mod also affects the other modes of input you are going to either have do figure out how to remove it, figure out how to view a PAL source (not easy for most people) or sell it some guy in Europe.