CMT(JUR) reported that rear cab to cab knob able to be removed from the casing. Staff(BGB) checked a nd confirmed rear cab, Cab to Cab knob can be remove and una ble to turn both ways. ~~~~~ 3504 CMT(JUR) reported cab to cab knob able to be removed from the casing. Staff(BGB) confirmed 3504 cab, Cab to Cab knob can be remove and unable to turn both ways.  3504 Cab to Cab knob screw resecured. Tested Both PA & Cab to CAb operation - OK. Huzzaidi 45273