Fast Battery Drain, 1 Cap Short to GND, a Few Others Short Across (What's Next?)

Nintendo Questions Nintendo Switch Lite
1

Hi there! I am hoping some of you geniuses could help me diagnose my girlfriend’s switch lite.

It turns on, charges, and plays games with no trouble whatsoever, except it drains 1% every 2-5 seconds. I have tried 2 replacement batteries, both showing the same issue.

I have checked pretty much every cap on the board at this point:
The cap in Red is short to GND on both sides,
The cap in Green is short across, 250Ohms to GND on both sides
The caps in Blue are short across, 17.8Ohms to GND on both sides
The caps in Yellow are short across, 75Ohms to GND
The caps in Orange are short across, 520Ohms to GND
The cap in pink is short across, 6kOhm to GND

I am not sure how to proceed, other than the one cap being short to GND is clearly a big issue. The fact that this switch still works perfectly other than the fast battery drain is throwing me for a loop, so I’m hoping one of you can tell me what that cap is for and how to proceed in fixing this thing. Any suggestions?

Google photos link because I am unable to embed media apparently:
photos.app.goo.gl/fBUL8RvMfBSUe9JBA

2

The components you marked are not caps. They are coils and they should have the same reading on both sides. If not, they are defective.

Did you test how long the Switch is useable apart from the state of battery indicator?

3

That’s good to know! The one marked in red is short to GND on both sides though, surely there’s no reason to have an inductor grounded on both sides is there?

I just got the unit back together, I will run a stress-test and get back to you on actual run-time.

4

The inductor marked in red is the 8316 negative rail afaict, so that would be normal.

Your resistance to ground on the inductor at the backlight driver IC is perhaps slightly low, though would need to connfirm you are taking those measurments realitive to ground and not other…

I would measure resistance to ground at your primary rails first (indcutors surrounding main max PMIC) first just to rule that out, excessive battery drain can normally be attributed to a short on one of these rails.

5

After running the stress test, gameplay lasts about 1hr before indicating zero and shutting down.

AFAIK I was checking relative to ground (one probe on the shield of the USB port). I will check those values around PMIC and report back!

6

Update: Out of curiosity I fired the switch up again after it shut down, battery indicated 1%, I fired up animal crossing and it has now been sitting and running animal crossing at 1% for the last 30 minutes. This makes me think fuel gauge issue? I’m not super familiar with fuel gauge on a switch, only with cellphones. Which components are responsible for this on the switch lite?

7

Fuel gauge is a possibility, but you have to run through your primary rails prior to rule them out, the lites use the same fuel gauge as regular switches and are well documented here, and you can test accordingly

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8

It’s still running 2 hours later at 1%. Should I keep going until it fully dies? From my reading it seems the switch shouldn’t boot at all if it were a fuel gauge issue, but I cannot think of any other circuit that could cause the battery indicator to read incorrectly like this, though I’m sure that is because I am unfamiliar with switch board repairs in general. Should I still rule out the primary rails first or does this information change anything?

9

My guess there is a problem with the battery indication. If the battery is really 1% you shouldn t be able to play hours.
I would charge the Switch till you can measure 4.2 V at the battery and then let it on till the battery reaches 3.3 V. After two or three times the battery indicator should calibrate itself.