Whacky a new circuit board will be of no use since other circuits will fail shortly after. I only have the DMD funtions still working, all else is up in smoke. Im running mine on 14.4v's with some cobbled together parts. Its much faster, like you said its geared wrong for 9'6v's. Since it uses a seperate board with relays, for the current, to the motors, any dmd you install will be isolated from the 14.4, so you can run a 7.2v, or a 9.6v DMD. I smitch mine with a relay, so it runs 9'6 or 14.4, poor mans two speed I guess. As far as the treads coming off, I dont use but part of the suspension, J&B weld the suspension on the front road wheels, and the two rear road wheels, solid. Keeps track tension tighter, dont shed the treads as easily. A real tank has a tensioner to compensate for suspension travel, also look in he front on the nose idler axle, you can shim it to tighten up the treads. Since Ive done these things, the treads stay on well, only have trouble in tall, 7 to 10 inch grass. Turns well on dirt or gravel, and shorter grass. You'll be better off to convert another DND board to operate this thing, like you described. The original Btr 500, if you could get a new one would only be a matter of time and it will go too.