(S (S (BASENP (DT The) (NN camera)) (VP (VBD had) (VP (VBN been) (VP (VP (VBG operating) (PP (IN on) (BASENP (PRPD its) (NN backup) (NN power)))) (PP (IN since) (NP (NP (BASENP (NNP June) (NN 30)) (COMMA ,) (BASENP (NN 2006))) (COMMA ,) (SBAR (WHADVP (WRB when)) (S (BASENP (NNS engineers)) (VP (VP (VP (VBD switched) (PP (IN from) (NP (BASENP (DT the) (JJ primary) (NN power) (NN supply)) (PRN (LRB -LRB-) (QT (DQL ``) (BASENP (NNP Side) (NNP A)) (DQR '')) (RRB -RRB-))))) (PP (TO to) (NP (BASENP (DT the) (NN backup)) (PRN (LRB -LRB-) (QT (DQL ``) (BASENP (NNP Side) (NNP B)) (DQR '')) (RRB -RRB-))))) (PP (JJ due) (PP (TO to) (BASENP (DT a) (NN malfunction))))))))))))) (PERIOD .))