To determine {TAIL ~ which subsystem} of {HEAD ~ imprint head} 18 contributed to, or caused, the anomaly, the subsystems could be systematically replaced 
To determine { TAIL ~ which subsystem } of { HEAD ~ imprint head } 18 contributed to , or caused , the anomaly , the subsystems could be systematically replaced
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH