[Doc Wu]

I just went through this myself...

First of all, from what I've read, the only allowed battery is a 7.2v battery pack such as the one used as the back-up battery on the RC. For testing, though, you could use a 9v transistor radio battery (009P style)

The coaxial connector is included with the chicklet. If you don't have it or need another, they are available from many sources such as Radio Shack. I don't know the exact size, so bring it with you and they'll find one that fits.

The Positive connection connects to the center of the plug. The negative goes to the outside. You will need to unscrew the cover of the plug, place the wires through it and solder them to the tabs inside. (I just read in another post that the chicklet is protected against reverse polarity. But do it right the first time and save messing up the tiny connections in the plug!)

There is very little room for the wire and soldering. I suggest a small, pointed solder iron and use care to solder the wires neatly using the holes in the tabs. Use small (18-22 ga.) wire. I also recommend some heat shrink tubing over the center tab so they don't short out. It was a tight fit when I did mine.

The 7.2v battery pack has a 2-pin connector similar to a molex connector on it. I haven't found a place to buy those exact connectors, so I used a spare back-up battery pigtail with the push-on crimp connectors, then put two male crimp-on (tabs) connectors on the coaxial plug lead. It's a kludge, but leaves the battery and pigtail unmodified. The battery can still be charged using the standard charger.

Next step here is to mount the chicklet and battery in a small plastic box for protection and build a short 15-pin cable to extend it to the port on the OI.