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IIRC U33 should have 3.3 volts on the large tab. If it's bad you can get these chips from mouser.com for pocket change. (plus s/h of course) Search for ZLDO1117
If the voltage is low you can sub the 3.3 V from a bench supply for test purposes. Expect it to draw the better part of an amp. If you replace the IC be careful not to break the teenie-tiny surface mount resistors near the IC. I like to put a glob of 60/40 solder on the pins first, then remove the solder with solder wic, and this draws away most of that lead-free solder crap they use at the factory. Then pry the pins up gently with a needle while heating with the iron.
Last edited by Geoff Bourquin; 03-05-2012 at 09:37 PM.
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