the power button on the idol 3 can be finicky as they are prone to failing. they ARE soldered to the circuit board so I would advise finding a local electronics repair shop or good friend with minimal soldering experience- seeing as the actual replacement is as simple a solder job as one could imagine . the component replacement, itself, is about $8.00 online.
http://www.ebay.com/itm/Alcatel-One-Touch-Idol-3-6045-OT6045-Power-Button-Flex-Cable-On-Off-Key-/171029243190?hash=item27d2232536:g:AhoAAOSwuLZY0axf