Switch won't power on, multiple components hot after solder attempt

[Makenai]

Hi all.

So what was just a simple SDcard port replacement turned into an absolute nightmare.

This is my first time soldering on a motherboard and I started out with some cheap equipment from Amazon. First off not causing any problems but not able to get any solder to adhere, the solder iron I got was useless and the heat gun I got didn’t get anywhere near hot enough.

The switch still powered on and worked at this point it just didn’t have the SD card connector on the board.

I then got better equipment, 450 degree solder iron and heat gun. now the solder adhered… And I was such a nooby that I thought I was doing a bad job when I just wasn’t seeing the solder had already melted and ready to join the connector. I used too much flux and too much heat.
Twice I had held the heat gun over the board for at least 30 seconds without moving the gun because I thought it needed that much to get the solder melted and connections made.

The other mistake I made is leaving the switch in the actual shell… Melting some of the plastic at the sides.
I’m not sure where it came from, mobo or plastic housing but when I did this I did heat it up till smoke came from under the board twice.

I also lost a resistor from just above the SD card connector in the previous attempt but it didn’t stop the switch from turning on.

I’ll attach some imagesbelow.
As you can see I also lost the switch connector port. And I’ve circled the resistor lost above the SD card port.
I removed the SDcard port I soldered on as I had lost a pad and thought it might be causing the issue.
I have also circled other parts on the back of the board which have solder on them suggesting they are missing a component but not sure.

I’ve been watching a ton of YouTube vids and read a bunch of threads since. I have ordered heat shields and I have some copper pads coming to make repairs for the SD card port, I also have a better magnifying glass setup with board holder coming.

I have tried testing with multimeter in line with all the vids I’ve seen online but honestly I have no idea what I’m doing. I thought I had shorts somewhere around the m92 or bq but when I measure voltage with it on charge I get expected results.
However the switch goes straight to 15v when plugged in.
I’ve checked resistance and continuity but I can’t really tell if I’ve got shorts or not. I’m mostly seeing things as fine.

I won’t get a thermal camera but I’ve tried the IPAlcohol on components when turning it on and I thought the hottest parts were BQ and control chip on the back. Although the ram, CPU and the other bit that connects over the WiFi chip all get really hot too.

When I connect it to dock the green light flickers but goes away.

I feel like I’ve accidentally done a reflow and damaged components or shorted somewhere but troubleshooting and diagnosis is challenging. Any help and steps from where to put the black where to put the red level of experience would be incredibly helpful
Thank you.

[Makenai]

I can’t seem to post images but I imagine they will be really helpful!

[Calvin]

You can uplaod images at a hoster and share the link. If you can not share the link, add a character in front of the link or inserd the link as code

[Makenai]

I see!

Here’s a drive link: Let me know if you need better or more specific photos

Also noted that my boards layout is different to the examples in the pinned thread on the motherboard schematics etc

Ahttps://drive.google.com/drive/folders/15sYEtmMYrXSfZpqtubrPiz1wN_EKZIvA

[Calvin]

missing resistor 0201 10kOhms

n.c. (empty)

n.c. (empty)

[Calvin]

For resoldering the sd connector and the missing Joycon connector I would apply heat from the backside. It is very hard to solder the connectors from the frontside, without burning them before the solder is molten.

To the fault, that the Switch isn’t starting anymore it could be many things. I would start with an usb tester and check how the power consumption looks like. (Normal: 0.45 A → drop to 0 A → 1.45 A)

[Makenai]

Whats the best way to go about that with just a multimeter?

[Makenai]

Oh sorry I didnt see you said with a usb tester. I’ve ordered one and will update.

[Makenai]

15.34v 0Amps

[Makenai]

Didn’t ramp up or change at all just straight to that

[Calvin]

I guess the little fuse obove the usb port is blown. Check for continuity.

[Makenai]

I’ve just checked and it beeps so I have continuity through the fuse.

[Calvin]

Does the supply voltage reach the m92t36?

[Makenai]

I measured what I think is pin 6, the top right pin of the chip when you look at it with the writing the right way up.

with just charger connected I had strong fluctuations between 0.01 and 0.010 vaults with multimeter at 20 in dc range.

When I shorted the power on pins to turn on the switch it dropped that vaultage down to a stable 0v before jumping back up to its fluctuations.

when I connected the battery without the charger connected I got stable and slow dropping vaultage from 0.05 to 0.01v. Again when I try powering on it dropped to 0v

[Calvin]

At the m92t36 the round marking is for pin 1. At pin 9 the supply voltage should reach the ic.

[Makenai]

Thanks I tried checking but made a rookie mistake and shorted it when attempting to test it because I was rushing so the usb voltage/amp meter doesn’t show anything when connected now. Fuse is still good. Will replace m92 and get back to you.