Benjamin Marks
Veteran
This summer I noticed both a vertical line of dead pixels AND an odd collection of dust-like spots in the upper left hand corner of all my M9 photos. Tried bulb blowers on the odd dust spots. Tried canned air. Tried a compressor. Tried special sensor cleaner with specialty swabs. No dice. Sensor cleaning had no effect. Off the camera went to Leica who announced . . . <drum roll> full replacement of the sensor and metering board and a general CLA to factory specs. I bought the camera three or four years ago; I thought the thing was out of warranty. So: Happy customer. The camera will be back in my hands, estimates Leica, at the end of the month.
Happily this nice treatment seems to be the rule with sensor problems. 
I bought a used M9 that turned out to have some hot pixels... Leica NJ did whatever they needed to do to address this at no charge, even though it was out of warranty period and not with the original purchaser.
I bought a used M9 that turned out to have some hot pixels... Leica NJ did whatever they needed to do to address this at no charge, even though it was out of warranty period and not with the original purchaser.