1708 not turn on, U3 Incredibly HOT!!

[renan.horste]

Hello guys, i have a 1708 controller, and my U3 ic get super hot when i press de Xbox Button to turn on, im already change the IC but dont solve my problem.
Any Sugestions?

[RDC]

U3 makes the 3.3v, so the first thing to try is just plug up the USB cable to the Top board alone, no bottom board attached, and see if U3 outputs the 3.3v it is supposed to. If it does, there's a short on the 3.3v rail on the bottom board somewhere, if there's still no 3.3v then the short is on the top board.

Schematic of the 1708 top board is here - https://www.acidmods.com/forum/index.php/topic,43981.0.html

[renan.horste]

I make the test, the top board have 3.3v in output.

[RDC]

Your MCU board has a short on the 3.3v rail somewhere then.

Best way to try and find it would be to inject 3.3v onto that rail of the MCU board with a bench top PSU and see what gets hot first. Could just be a shorted Cap in there, could be a chip that's gone south. A thermal camera for that is great, but a Q-tip and rubbing alcohol will work just as well as it's going to evaporate much quicker off of anything in there that is getting warm.

[renan.horste]

I solve the problem!!
A short in two capacitors in up side of the wireless board, change them and the short in 3.3 line is gone!