No ROLL control

CX20 OS FC V3.2.1 will not ROLL left or right from RC. Swapped out receiver and same issue.
No movement in RC Calibration in MP. Could this be a FC issue? Have another V3.2.1 OS FC and compared params and they are the same. Any suggestions?

If MP is not seeing any movement of that channel during a RC calibration, and its the only channel with a problem, I’d first look to see if it’s a wiring issue ( break in cable?) between the reciever and the FC. If that doesn’t fix it, try verifing that the reciever is really putting the “roll” out on the place u expect, by unplgging the channel, and plugging a test servo directly into the receiver. if this servo moves when TX sticks are “rolled” , then the RX output and channel etc are all good. final test is to put a servo tester into the FC in place of the cable that would normally be used for “roll”, and try the TX calibrarion test again… if the channel moves around in-sync with the tester ( most testers have a knob that u need to turn), then the FC is working fine.

David…thanks for the info. I attached a servo (first time trying this) to the 4 channels (A-E-T-R) and discovered the connector from A to FC was reversed. Great troubleshooting tool. Thanks again!