Switch lite doesn't charge but boots, no shorts, no visual dammage and random readings

Nintendo Questions Nintendo Switch Lite
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1

Hey everyone ! I hope you’re doing well and have a fantastic day :blush:

I got a switch lite from second hand market, that was listed as “not charging”. :battery:

Troubleshooting steps followed :

First step for me was to inspect usb c port. No visual damage, so I moved on to next step : usb-c ammeter.
At first I got a pretty normal reading : around 0.4 amps, battery symbol. But after a lot of waiting, the battery still didn’t seem to charge, and the amp draw fell to under 0.1, eventually reaching next to 0. :x:

I tested all caps next to ICs, no shorts were found. :heavy_check_mark:

I tried to switch the battery with another one (don’t know if it’s a good one or not though), and the same thing occurs : the amp draw stays at ~0.03 on one side, ~0.05 on the other side. Battery’s voltage was at 3.72V.

After a bit of research online, I found out it was maybe the BQ charging IC ; so I swapped it with a donor one (once again, I don’t know if the donor was working). Result : same readings, around 0.01/0.02 amps. Having the battery plugged in, or not.

When trying to charge the switch for the first time, I recall the battery symbol going from red to near-full for an instant then going off. Which makes me doubt on the fuel gauge IC ? But since it is a BGA chip, I’d prefer not having to deal with it if I’m not 100% sure I’m going in the right direction.

To be honest with you I’m a bit lost, since the random-like behaviour of the amp draw seem to drive me to different directions :thinking:

My questions :

Is it something you already encountered ? What steps would you follow next in this situation ?

Since I don’t know if I can trust the batteries, should I consider buying a known good one, or is it extremely unlikely my issues come from 2 different batteries ?

Thanks a lot, and I wish you once again a wonderful day :grin:

2

If an empty battery symbol appears although the battery reads 3.7 V, I would put my money on the tiny 9-bga-fuel gauge chip and replace it.

3

Did you even test cc1 and cc2 pins diode reading?

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4

Hello @Calvin , hello @jkyoho ! First of all, thanks a lot for your answers. You are legends to me, as I saw you replying years and years before today aswell… Thank you for being here and help us :grin:

I did test cc1 and cc2 pins, I get a classic .5v reading on them. Something I just saw though, is that I don’t get a diode reading on the central battery connector pin (I’ve seen on youtube it is supposed to have one ?)

So it would further confirm the fuel gauge IC is the problem, right ? :thinking:

5

yes, battery connector central pin is for battery thermal measure, which goes straight into fuel gauge ic A1 pin

6

I see, noted !

I will try to reflow this chip with no real hope, and order new one if necessary ! Since I cannot reball donnor yet.

I will post my results here as soon as I move on so future people gets updated !

Have a nice day all :slight_smile:

7

Hello everyone ! I hope you’re doing well :slight_smile:

Current state of things : i tried to reflow the chip, but it does’nt change anything. So I ordered new ones and will attempt to replace it in a few days :smiley:

One thing is bothering me though : how come, even with the fuel gauge removed, and without a battery connected, the board still maintain up to a 0.1 amp draw ? Isn’t it supposed to draw nothing at all, if no battery is connected ?

Anyway I will keep you updated as soon as possible ! Have a good evening :slight_smile:

8

I could only image when emmc not communicate with CPU(stuck on RCM) the board would draw 0.1amp without battery connect

9

Thanks for your reply !!

Here are current state of things ; I received the MAX ics today, so I replaced the fuel gauge. I think I did okay ; visually it doesn’t look too bad, and now I get back a 0.6v reading when probing the temp connector in diode mode.

Although, the issue doesn’t seem fixed yet ; when pluging the original charger in, the ammeter shows a 0.04amp draw then instantly resets, and this loops endlessly. Could it be the battery itself is faulty aswell ? (I’m asking, because this battery comes from a water damaged console, and I don’t have any spares)

As always, thank you for your precious help ! :smiley:

10

Do you have charge port both side 15v 0.004A(original/PD charger) without battery connected?