MARIE broke down - - we know that solar radiation varied while the two spectrometers were running...

MARIE was intentionally turned off in August 2001 because of a temporary glitch that prevented it from responding to a downlink command while Mars Odyssey was still en route to Mars. The instrument did not "[break] down," as you put it. The mission managers wanted more time to troubleshoot what they thought, and what turned out, to be a minor problem. They also wanted to wait until after MOI and aerobraking were completed before reactivating the experiment. Some cruise data and the aerobraking data radiation were lost, but that was not considered critical. At any rate, the instrument was reactivated shortly after the start of the mapping mission in March 2002 and has been running continuously (along with "the two spectrometers," presumbably you mean GRS and THEMIS) ever since.