TC reported MCH jammed. Unable to proceed in ATPM. TC switched back to AM mode -ok. ~~~~~ TC reported 3515 MCH jammed. Unable to proceed in ATPM. TC switched back to AM mode -ok.Level 3 L3 3515 Found when hold MS down, or when pushed down too hard into position, the MS becomes stiff and remain in a bottom position that can cause MCH unable to be moved. Open cover and found MS handle slightly misaligned with torque seal intact. Remove the MS mounting and realigned the MS. Checked that there are no stiffness and MS will jump into correct position even  when MS actuated and held down in ATPM position. Tighten & retorque 4 holding screws to 5.8Nm as per HMM. Function test multiple times no more MCH stuck issue. Done by Kenneth 44860