Xbox one 1697 controller shorted need help

[jayg]

Hello, just trying to fix a 1697 controller that doesn't turn on, neither usb or batteries, and gets hot.
A little note, the two resistors near Q4 are from an old 2013 Day One controller board, as well the C3 capacitor, as they were missing from this board.

So the main fault is the board won't turn on, and when plugged with USB, U3 and the capacitors C22 and C23 start getting really hot.

Capacitors C23 and C22 are shorted, but if I remove the MCU board the short disappears. Worth mentioning that, the Power board works fine if plugged to another old 1537 MCU board.

So, I did a little testing in his original 1697 MCU and there are a lot of shorted capacitors, precisely C9, C8, C1,C12, C43, C11,C5 C4, C3,C2,C16,C41,C6,C7,C246,C244,C29.
I've tried injecting 5v in some of those caps and U1 get hot.

What's your advice on this guys?  maybe bad U1 chip? those capacitors are most likely all under that ic. Thank you all in advance

[RDC]

If U1 wasn't bad it probably is now since you've injected 5v into the 3.3v rail.

Only use 3.3v and dampen certain spots of the board with rubbing alcohol and then inject the 3.3v and see if it evaporates off of any one component faster than the others. This test would have been better done before injecting the 5v in there, but you could get lucky and find it's just a single cap causing it. If U1 is still the component that gets hot first, consider it a parts board or candidate for learning how to do some BGA rework.

[jayg]

Lol, what a dumb move...... Ok so later I'll try with the 3.3v, but yeah most probably I just killed U1. Is this chip reperible? Or just from spare boards?

[RDC]

Even if you could find a brand new MCU, you'd have to get M$ to program it before it would work. Another board is the only real place to get one. Bound to be some of them around that have had other parts of the PCB damaged from a stick swap or crapid fire mod gone wrong, so they should still have a good U1 on them.

[jayg]

Soo I think that's definitely not an option, unless Microsoft suddently offers free ICs programming to all their beloved costumers 

Ok so:

I've injected 3.3v to the pin 4 of J6 connector, and that caused first to L1 to get hot (I did the iso alcohol method), and then after I removed It, L2 got hot like the previous one. BUT, being inductors, *I assume* if they got hot is not their fault.

Now If I inject 3.3v the board doesn't short anymore and takes 0.1 amp.

What are my options now? Shorted caps have became lesser. Now only C9,C8, C1, C6, C7, C3, C4  are still shorted. C41 is like a partial short? It displays 0.103

[RDC]

I haven't done a schematic of that one, but just did a quick test on a 1697 here and removing the Inductors has most likely just removed the path for the 3.3v to get to whatever is shorted, which seems to be U1.

Left side of L1 is 3.3v, right side is going to U1.
Right side of L2 is 3.3v, left side is going to U1.

[jayg]

I confirm U1 is shorted, tried removing those caps, but nothing ever changed, short is still present. Thanks for your help so far.

So, I know this question may sound stupid and ultra semplistic , but since U1 works with 3.3v, is there any chance for the controller to be powered only via the 5v USB source without that chip?

[RDC]

U1 pretty much IS the controller. Without that chip nothing works. It's the 'brains' of it all.

When you plug the controller into USB, that 5v gets converted to the 3.3v that most of the controller uses on the Top Button/Power board.

[jayg]

Ok, just going to leave that for parts, thanks