P13USB keeps blowing after few days of use

Hello. I got a nintendo switch that had obvious damage to the p13usb. There was a hole in it, plus the two inductors circled in red in the image were burnt. After replacing the components the switch was running for a few days then returned with the same issue. Swapped it out again (thinking it would blow again, but couldn’t find any other issue). It returned 2 days later. The p13usb was blown in the same spot (marked in red). The inductors seem to go directly to the usb c port, but the client is certain that nothing was connected to the switch at the time it blew the second and third times. This last time It was just sitting on the table while they were eating and suddenly it shut off by itself. Does anyone know what could cause this if nothing is connected to the switch? I would have guessed it being the dock or charger, but the dock hasn’t been used since the first swap, and the charger has been used on other switches just fine. Any help in diagnosing would be awesome. Thanks.

Edit: Seems the forum wont let me add pictures nor links to pictures to show the damage. The inductors burned are the leftmost ones, labeled as lines sbu1 and sbu2 in the diagram I found on this forum.

Did your choke filter/inductor survived? I’ve seen that 2 lines blown/burn-down but after replace inductor and pi3, it never comes back to my place.

The first time they did not survive. The second time, I decided to just jump them since I didn’t have any more, the jumpers are intact. Any Idea what I should be looking at to fix the issue reoccurring? It seems sbu1 and sbu2 lines go straight to the usb port.

So I have checked the sbu1 and sbu2 lines with this burned p13usb still on. The sbu1 line gave a value of 730, and sbu2 gave a value of 60. After removing the p13usb, both gave oL. So something shorts inside the p13usb and lowers the resistance of sbu2 line maybe? Why is this short re occurring? I have checked the charger with an oscilloscope, no fluctuations, plus the client assures me that nothing was connected the last two times it died.

I would check the resistance to ground on 3V3PDR as pehaps it’s being pulled low by something which is causing the continuous failures of the P13 IC

I would also check out your other primary/critical rails resistance to ground to see if there is another issue upstream.

I’d be checking for continuity from one P13 filter to the other (in case a USB pin is bridged or has junk/corrosion in the connector) if all ok, then check for resistance from one filter to another incase there is a “high” short.

I’d find one of @Calvin diagrams of the P13 area and after you have installed the new IC check to make sure they match his diagram, incase this is a soldering related issue.

Don’t do this.

Thanks for the suggestion. I have found a diagram from Calvin and checked every point on diode mode, they all seem to be there, but all are off by the same amount (probably due to the multimeter, wires, or motherboard model?), eg. the vcc in his diagram has 432, mine gives 370. Aux + and - on his is 740, mine are 700, and on the right side of the chip there are some that on his is 432, on mine 370. So the lower the value the more off my measurements are compared to Calvins. But all are present and seem to be off by the same amounts. (Also no resistance at all from one filter to another at 200k).

This could either mean something is bad, or my measurements are off due to the multimeter which I think is most likely. The switch is currently working, and I have been charging it through usb to computer 2.0 port (takes forever), and It has lasted all night. I am starting to think that maybe the client was lying, and did connect it to their charger. I have their charger and have connected it for small amounts of time to check for spikes on the main 15v line and the sbu1&2 lines, nothing happened. But is there a way I can be sure? I get no voltage (through oscilloscope) on the sbu1&2 lines (the ones that constantly blow), and no noticeable spikes on the 15v line.

your 50-100 diode mode constant off should be DMM related, so nvm.
FOr the Sbu1/2 line, you need to make console in Dock mode and measure, otherwise charging it would not use those lines

Thanks. The kid says he hasn’t used his dock. He only uses it as handheld, but I don’t know if I can believe them. I have had it on and working all weekend without an issue. It seems it’s only when they take it home that it blows. Maybe I should just leave sbu1 and sbu2 unsoldered, they say they don’t use the dock anyway. I don’t know what to do, I have already replaced it twice, if it comes in one more time I end up loosing more money on it then what I charged. I don’t like leaving things wrong, but it hasn’t once blown here with me, but lasts less than two days with them.

What’s your resistance to ground on 3V3PDR, this can be found at either the larger cap right next to the P13 IC or pin6 of the m92 IC

You may have already mentioned this, but, is the charger a nintendo branded one or third party?

Regardless of if he truly uses it in the dock or not and you may have already mentioned this also, but is the dock genuine?

I’d make the repair stock standard, and if the dock or plug is non genuine say you can’t guarantee the repair moving forward, this is pretty standard practice.

going forward, it might be wothwhile getting one of those USB ammeters which log over time and can sync up with your phone, then picking up a USBC extension for the dock, that way you can leave it running for a few days and possibly catch an anomoly.

If both the dock and plug power are genuine and you’ve had no issues for a few days using them, then I would be asking (out of concern more than anything) as to which mains outlet theyr’e connecting this to and if it is routinely plugged into the same outlet and more importantly the outlet in which the failure occurs, then my concern would be bad wiring (likely screw terminal related) at the socket and would advise that this is checked, especially if it’s in a kids room.

Thanks for the reply. He brought the charger with him, it is the original charger, and it is what I have been using to charge the nintendo. I saw no spikes on the sbu1 line using an oscilloscope on a 1v ramp trigger, during a full charge cycle. The dock is also original but not used at all, so they say, but was not brought in. I normally warn of no guarantees when using 3rd party chargers and docks, or if I can find a fault in their charger, but this time there is no damage and I see no spikes on any of the charger lines.
The 3v3 line, measured at the big cap above p13usb is around 100kohm.
I will look into the usb ammeter you mention. I dont repair many mobile devices, mostly large consoles and computers, but with the switch it seems to be a good investment.

That’s perfectly fine.

Yeah, I’d be suspecting pin damage on the dock side USB then or another fault at the dock, he may not use it “docked” on the TV but may use the dock as a stand or simply to charge and not know the difference.

Would still definately ask them about the mains wall sockets they were connecting the nintendo charger to though as your statment below is standing out to me, and if it’s not the dock at fault then it’s got to be a variable in the home, and the only thing I can think of is an AC mains fault at that point.

You’re right, he could be using is as a charge station. I’ll ask him to bring in the dock this week, so I can inspect it. Thanks for the help.