The buffer is usually needed on engines with a two wire IR LED. Not needed on the engines with a three wire LED as they come with a built in buffer. Replacing the two wire LED with a three wire will also solve this issue. To make the swap you would also need a two part housing to accomodate the PC board the LED is mounted to. The 5v supplied by the R2LC is more than adequate and doesn't affect performance of the radio board.