I have 4 R700 FM receivers and two of the new 700 PCM recievers. They are absolutely bullet proof. I run them all un unregulated 6V packs and after hundreds of flights, they have all run flawless. I even have two of the FM units in Gasoline powered planes and have not had a single issue.

Are you using a JR Switch?

It is possible your LHS has received 2 bad receivers (although unlikely) are you ABSOLUTELY CERTAIN the LHS gave you a new crystal. Sounds to me like your receiver is getting hits and it could be due to a oscillator freq shift.

You have done everything each of us would have done with the exception of changing channels and using a different brand or model receiver.

I forgot to ask - is the engine running ? I am assuming you have not ever gotten that far yet?

DP