hi there,
i know im not rik but im hear first lol
Tamiya electronics have changed alot, the older 80's version like yours if im right is the double clutch version, it has a single gearbox taking power to each drive sprocket, but clutches that do the turning

anyway the DMD is like the brain, except the older versions such as yours will have a DMD T-01 or 02 i think. The newer tamiya's have sound systems and are generally alot more technically advanced, and you get the newer DMD and a MF (MULTI FUNCTION) unit, which doesn all the extra bits like lighting and recoil ect.. These DMD and MF units (including the older ones) and boards, electroical ones, concealed within a black box that will be hidden somewhere in the tank, probably under a jumble of wires if its anything like my Tamiya jagdpanther

the boxes are fairly big however.
cheers, hope this helps... and makes sense
Matt