Switch not boot 0,02A but no shorts


I need some help to diagnose what’s happend with that switch.
If I connect only the usb charger (official) I got 0.02A, but if I plug battery and charger all the branch from the inductor next to BQ24193 to the battery connector get too heat, the coil burned my finger, and I got 0A with the usb tester.
M92 pin 6 I got 0V only with usb charger.
With only battery connected I get 0v pin 5 and 6 on M92


I founded a shorted cap near lcd connector, also a resistor or fuse next to it

Does anybody knows this cap value and size? The other component is it a fuse or a resistor?

You have a short on your SYS rail. Put one probe on ground and the other on either side of the large inductor near BQ to verify resistance.

Once you’ve confirmed the short above, pull the BQ IC and see if short clears

Do you mean this inductor?

In diode mode i get 363 on both sided
In continuty no beep
Tested all ohm scales without any value

Yes, this is the one that was hot right?

Resistance please.

After check continuity across it, if there is none then it’s failed open as a result of the short on SYS

Sorry I put the probes on each side the inductor and 0 ohms or beep on continity mode

And that’s zero ohms with one probe on ground?

Nothing, the tester doesn’t show any measure

Leave your first probe on ground and put the other on the other inductor pad.

Is your meter auto or manual ranging?

I leave the black probe on the usb shell (ground) and red probe on each pad of the component. No value from meter, is manual range and tested all ranges without value

Doesn’t make sense, it’s normally in the kiloohms.

Try using a screw hole pad as your ground to rule out probe error

Its so weird… Both probes on inductor pads show 0ohms but I move black probe to ground and I see the value raising and decresing to 20Mohms ( meter limit) maybe this inductor it’s faulty? I am waiting for a new bq ic to change ( also gets hot).

Could this inductor makes 0v on m92 pin6?

If you get continuity across the inductor then it’s fine. Was this the inductor that was getting hot earlier? just to confirm.

I think your BQ IC had originally failed short and in turn was pulling your SYS rail low, i think now as a result it has now gon open circuit (OL) it’s cleary still suffering a short internally which is why it’s getting hot.

Would reccommend you refrain from powering on this board less you damage something else. Remove the BQ IC and replace when you get another.

Just say, when replacing, don’t use low melt solder :slight_smile:

Severence thank you so much for your help
I would update once the new ic arrives and install it

Sorry i forget to answer your question
Yes, the inductor gets too hot makes me a burn in my thumb, also bq gets hot, battery connector and the fuel gauge ic

Interesting if it still gets hot even though your measuring OL on it relative to grund, but perhaps something is changing under load as a result of the fault on the BQ IC.

The other areas getting hot make sense i suppose, hopefully replacing the BQ IC resolves your issues and hopefully nothing else has been damaged as a result :slight_smile:

sounds like BQ24193 needs to be replaced if it gets hot and is only pulling .02a

At least the new BQ arrives and also a M92 to change because in another test with the usb charger now I have 3 caps shorted, I desolded both IC and from the other side of the BQ IC another chip and a resistor dropped out!!!
Now I wasted all my time to try to solde them again when I solde the new IC I’ll update the results

I would guess you mean the fuel guage and the current sense resistor fell off?

It’s entirely possible this a secondary fault because of your prior rework above.

If you want my advice, (I’m not saying this to be mean) but stop what your doing, practice on a donor board first or if you have a friend who has more experience ask them to resolve this problem for you. Continuing will very likely result in permanent death of the console as it’s turning from a simple fix into something very different.

BGA ICs require stencils and solder paste.

Don’t plug in the battery or USB into this board.

Not that ic, the other near to fuel gauge, I think it’s joycon controller.

Lesson Learned!!