The 9V batteries run the transmitter and receiver; the C cells run the motors. When I first tried to move the thing under its own power, it wouldn't; finally it began to jerk epileptically in place. I was able to get the thing to drive down the front hall of the bunker, but it kept stopping or jerking to one side. So I repaired to my rocking chair and began dissecting the beast to try to figure out what was wrong.
Finally I realized that the problem wasn't in the truck, but in the transmitter, after taking the front panel off the transmitter and moving the contacts with a screwdriver. Bad contact means intermittent modulation to the outgoing signal, means truck has a fit.
Took the circuit board out, scrubbed down the contacts with a pencil, reassembled...and now it does nothing whatsoever.
I took it apart again, closely examined the whole thing, put it back together--nothing.
Well, it was a nice idea while it lasted. I guess that's how it goes, sometimes, when you take an old machine out of storage and try to use it. Let's face it: I bought this damned thing twenty-seven frigging years ago.
I can only hope that the C cells simply ran out of juice, and that's why it wouldn't move, but it's not the way to bet. One of the worst parts of this is that I tossed a lot of the micro RC cars that I got in 2002-2004. At least one of them was 27 MHz and its controller might have worked with this truck...or might (probably) not.