Shaun,
I believe the last poster Phread has it right. Use a vibration source on the repaired receiver. Have your buddy tapping on the receiver with a pencil and do a range check with the transmitter antenna down. You should get at least 60' distance.

Check the servos by holding some tension on the arms while another person operates the transmitter. They should still operate smoothly, or take them apart and visibly check the gears. I'd do both.

Wiggle the on - off switch to make sure it has no glithches. Test this by plugging in a small 6 volt lamp (#47) into a spare servo socket. Just use just the red and black wires. You should not see any flickering.

The receiver does not have to be in the plane to do the testing. Just make sure the antenna wire is fairly straight and not coiled up.

Good luck.
John