A diagnostic system for monitoring failure modes and adverse conditions that have mechanical signatures that can be detected in a scanning system that detects characteristics of a sheet of material during linear translation along a translation axis of a bi-directionally driven mobile detector device, the diagnostic system comprising: (a) the scanning system being monitored which comprises: (i) a first elongated member including a first beam structure that extends along a first direction wherein the first elongated member supports a first carriage that is mounted thereon; (ii) means for driving the first mounted carriage, that supports a first sensor head, along a main scanning direction; (iii) a second elongated member including a second beam structure that extends along a second direction that is parallel to the first direction wherein the second elongated member supports a second carriage that is mounted thereon; and (iv) means for driving the second carriage, that supports a second sensor head, wherein the scanning system includes a common drive mechanism comprising a single motor that moves both the first carriage and the second carriage; (b) an accelerometer configured to measure vibrations generated by one or more components of the scanning system including the first beam structure or second beam structure and generating vibration signals indicative of operation conditions of the one or more components including failure modes and adverse conditions thereof; and (c) means for correlating the vibration signals to modes of operations of the one or more components of the scanning system which compares the vibration signals to reference signals to determine the state of the one or more components including failure modes and adverse conditions thereof (a) the scanning system being monitored which comprises: (i) a first elongated member including a first beam structure that extends along a first direction wherein the first elongated member supports a first carriage that is mounted thereon; (ii) means for driving the first mounted carriage, that supports a first sensor head, along a main scanning direction; (iii) a second elongated member including a second beam structure that extends along a second direction that is parallel to the first direction wherein the second elongated member supports a second carriage that is mounted thereon; and (iv) means for driving the second carriage, that supports a second sensor head, wherein the scanning system includes a common drive mechanism comprising a single motor that moves both the first carriage and the second carriage; (i) a first elongated member including a first beam structure that extends along a first direction wherein the first elongated member supports a first carriage that is mounted thereon; (ii) means for driving the first mounted carriage, that supports a first sensor head, along a main scanning direction; (iii) a second elongated member including a second beam structure that extends along a second direction that is parallel to the first direction wherein the second elongated member supports a second carriage that is mounted thereon; and (iv) means for driving the second carriage, that supports a second sensor head, wherein the scanning system includes a common drive mechanism comprising a single motor that moves both the first carriage and the second carriage; (b) an accelerometer configured to measure vibrations generated by one or more components of the scanning system including the first beam structure or second beam structure and generating vibration signals indicative of operation conditions of the one or more components including failure modes and adverse conditions thereof; and (c) means for correlating the vibration signals to modes of operations of the one or more components of the scanning system which compares the vibration signals to reference signals to determine the state of the one or more components including failure modes and adverse conditions thereof