Switch intermittent charging after repair

So I got a low serial, MAYBE unpatched switch that didn’t charge or turn on and quickly realised the USB port had a few bent pins at the sides.

I replaced the USB port and still no life, found a few shorted caps around the M92T36 so replaced that, shorts were gone.

I did manage to knock the 0201 10nf cap off that sits between 5v and GND near the M92 chip but I see online that’s not going to stop the thing charging.

Plugged in a Samsung charger as I don’t have the official one and it started to charge, very slowly.

Then I unplugged, put it all back together and then it wouldn’t charge again.

Took it all apart, inspected my work, gave it all a reflow for good measure, cleaned it up, charging again worked so I put it back together again, testing as I went and fully back together, charging still worked so I left it for an hour or so, still on one bar but still charging.

I unplugged it to move to a different room and plugged it back in, now it won’t charge again!

It charged enough that you can turn it on and you get the Nintendo logo then the battery symbol but no lightning icon to indicate charging and it turns off again.

I’m a bit lost really. I tried the USB C both ways, same thing. There was no shorts around PI3USB and the filters were fine. Could it be the BQ chip? It’s just really odd how it’ll work one minute and not the next. I’m confident in my soldering, the port did work fine until I unplugged and replugged?

Tearing my hair out (and I don’t have enough to lose!) Anyone had a similar issue before or know where I should start looking?

Do a visual inspection around BQ to see if there looks to be any missing components. I had a weird board recently that would boot @ 0 amps and then 15-20 seconds later I would see .47a show up. Tracked it down to a missing 0201 resistor on BQ.

Photos are a big help, and as confident as you are in your soldering maybe give m92 another look if you had replaced it.

I renewed all the pins on the M92T36 and it’s been charging ever since. I guess I shouldn’t have been so sure of my soldering!

It is however charging veeeery slowly. Like it went from 30 to 42% in 15 hours and it won’t dock but then I’m still using that old Samsung charger at the moment. I’ve ordered an official charger ao we will see how that gets on.

In other news, it would seem it takes a payload so it’s definitely unpatched and was worth the effort!

Lastly I noticed joycon drift on both joycons. I’d placed an amazon order for replacements and then stumbled across a youtube video suggesting to place a piece of thin card behind the joystick module. Well, I’ve cancelled the amazon order, works perfectly!

great news, these QFN chips always give me a hard time. If you dont see a nice little pillow of solder on the pad leading up to the chip, chances are that particular leg isn’t making a good connection.

Interesting, although IMO these hacks really just mask the actual problem and will also eventually fail on you. Im not sure where you’re located, but I can get a six pack of joycon replacements for under 20$ on amazon. Cheap enough to just toss and replace, but if you’re happy you do you bub.

It seems to make sense, there’s not much pressure behind it and the joystick has a very thin base. Will see how I go. It’s only £5 for a pair.

In other news, my issue has returned.

It’s been fine charging all day with no issues, albeit slow and this afternoon there was a surge of charge where it jumped almost 10% in half hour! The adapter even got warm! Then nothing at all. Console says it’s charging, but it’s dropping. Adapter is cold but tested with my phone and it works fine.

CFW is turning out to be a massive pain too. In terms of getting anything to run properly. Starting to think I’m wasting my time with this thing.

can you get us some pictures? they’re a huge help. I Worth doing some probing on all the passives around bq, test the voltage coming out of that big inductor, then finally probe the test pad near the battery connector to see if you’re getting voltage there.

its also theoretically possible BQ is failing but not displaying a dead short. If you have a spare, might consider swapping it

It turns out it was the cable I was using. Must have a short or break in it causing unreliable charging. Got myself an official charger and now all is well, been working fine for a few days! :slight_smile:

Goes to show, don’t rely on a 3rd party or other chagers when repairing these, go oem to be sure! I could probably have saved myself a lot of headaches and several hours if I had!