RE: futaba 6exap failing
Put the original TX crystal back in, the one the TX is tuned for and then use the RX that came with the system and it's original crystal. Make sure the TX is in the PCM mode if using a PCM RX. Leave the lowest section of the antenna extended and just collapse the upper part.
Check your RX antenna is extended and not running near metal pushrods.
Report back on the results.