I think that you mean a 12 to 6 v converter. There are three terminal converters which will always give you the proper voltage. With a simple dropping resistor, the voltage will vary with the load. I don't really think that it is a big deal.
If you are cleaning up the platic, you won't want to use wood alchohol on the bezel because it will melt it. I know that from practical experience. Oh, also if yours has a straight back, the speaker that is commonly sold by Jim Carter and probably all the others, will not fit. If it is the slant back model, you can make the speaker fit. In the latter case, the one sold at Walmart does the job just fine.
