MTS

I have a M8 with a Spectrum moduel, and something is wrong. When ever I give it throttle or brake on the radio the servo only moves one way. If I reverse the throttle servo the servo only moves the other way. I am well familar with radios with display screens, i.e 3 channle synthisized JR, Spectrum DX3 and a Hitec Lynx 3D. I would fix this my self but I did not get a manual with the radio. If anybody has a link or file they can send to [email protected] I would really appreciate it.