I find that UseNet groups almost always suggest the most-complex and
most-difficult-to-implement solutions one can imagine.

There are three simple solutions...

1) Use rechargeable batteries. This won't be cheap, but the OP can operate
the boombox anywhere. This is an essentially fool-proof solution.

2) Find a 9V auto cord.

http://www.radioshack.com/product/in...ductId=3812864

3) Buy an inverter and use the power supply that came with the boombox.

http://www.amazon.com/Wagan-EL2402-S...75432&sr =1-2