This may help to find the problem. I was reading up on a transmitter signal monitor and found this one that you can make. Just hook it to your antenna and you can hear the signal from the TX. It might help figure if it is the TX or RX.

Parts:
1. one 001mfd capacitor
2. one diode
3. one 10uH RF choke
4. one miniature headphone jack
5. one plastic 35mm film container or something similar

Instructions:
Drill 1/4 inch hole center of the bottle cap. Mount a phone jack there with the terminals so they will go inside the bottle. Cut the leads on the RF choke and the diode to 1 inch. Two of the jack terminals have small holes: solder the diode lead into one hole and the RF choke lead into the other. Bend the free ends of the diode and the RF choke toward each other, and twist them together, trim them to fit in the bottle. Solder them to one end of the .001mfd capacitor. Drill a 1/16 inch hole in the center of the bottle bottom. Put the free end of the .001mfd capacitor through the hole and put the cap on the bottle. Plug a transistor radio earphone into the jack. Bend a hook in the capacitor wire, which hangs on the TX antenna. Turn on the TX and listen.

This was taking from the book !QUOT!Master Modeler Series Building Techniques!QUOT! by Randy Randolph

I hope this helps