I think wireless camera links are the best advance in technology to happen to the location sound mixer because it gives you the freedom to do your job the best way you can, I have rarely had an issue with my zaxcom system but here is a list of things to do before shooting and a list of possible problems you may run into:
1. Make sure your camera man is always listening to the wireless feed via his camera headphone jack since you have no way of knowing what it sounds like.
2. Make sure all attennas and power cables are secure to the unit. The only issues I have ever had it a lose power cable or attenna.
3. Make sure the unit is secure in a saddle bag or BEC box. I have mine wrapped in velcro, which keeps them extra tight in the saddle bag or BEC box.
4. Have extra cables and attennas in case something breaks.
PROBLEMS AND SOLUTIONS:
1. Unit will not power on: Check power cables are tight by removing them and reinserting them. Check batteries if your using them. Check Power Switch.
2. Unit is on but Camera Op hears no audio: Check headphone volume knob on camera, check transmitter in your audio bag, make sure camera is set up to recieve audio correctly.
3. Poor Range: Check to make sure tx and rx attennas are tight and secure, Make sure they are in good condition. Scan for new clear frequency.
With these simple tips and tricks your Zaxcom should preform well for you and make your job much easier.