Welcome to the hobby, we're glad to have you amonst us. FYI, You'd get more comments on your problem if you post it as a topic in the RC Tanks forum instead of the War Room forum.

Irregardless, please tell us what kind of Leopard you have. Tamiya made two, a Leopard 1A4 (in the 1980's) and the Leopard 2A6 (current production). The electronics on these models are quite different.

As a general rule, the quality of advice received is directly proportionate to the quality of information given. Take some pics of the wiring at your receiver connection, along with a pic of the overall tank (opened up) and post them with your question. As to the problem, it sounds like a common problem, but give us more info, and I'm sure you'll get lots of good advice.