RE: Spektrum DX-7 Problem ??
Regarding RX losing signal in very close proximity - it's normal. Others and myself experience similar when the RX won't pick up the TX if the TX is too close. Move it a foot or so away and all is fine. Apparently the RF section of RX is swamped by too strong a signal.
Regarding RX failure - sounds like symptoms of a poor connection - a lead or a dry solder joint in the RX maybe?