Sega TARGET BRAVO OPERATION GHOST Owner's Manual page 76

If the control unit does not operate satisfactorily and adjustments in TEST MODE are ineffective, it could be that parts inside
the control unit have been damaged. Follow the steps given below to remove the control unit, dismantle unit and replace parts.
To replace parts in the control unit, remove the speaker unit and detach the L and R covers of the outer part. Because internal
parts are inserted on the R cover side, work with the R cover facing downward.
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