Originally posted by popsracer
...For FM the Transmitter crystal MUST be the SAME brand as the transmitter to work properly. The receivers don't care...
I'm afraid that it's not totally correct. I tried crystals from the brand called "Central" on my Mars. Also FM 29Mhz. It worked perfectly.
TRF512, there are many possible reasons behind your problem. First of all, your antenna wire of the receiver might be broken inside the rubber wrap. 2nd, your transmitter module might be worn. It may be due to power-on long time or using high voltage (perhaps over charged) TX batteries. By this way, your module would be overheated.
I have broken my previous Mars with a freshly charged 9-cell pack which read 15.9V. haha. It seemed to be working but after a few packs, your problem occured.