Hardware The usual faulty switch off ebay full of issues.... Please advise.

[lpoolm]

So did what I haven't done for a while and bought a faulty switch off ebay..
So its the usual doesn't charge or turn on and it looks like its been worked on as the tab for the joycon next to the battery connector is slightly melted.
Checked the usual shorts inside and there was a short around the M92T36 chip which I found strange that whoever previously worked on this didnt change that too?

So I swapped it over for a new one and a fresh battery.

Progress the back light comes on but nothing on the screen? I thought crap, but when I touched the screen I heard some noise!!
It works, kind of, I can hear the touchscreen.

I plugged it into a dock but nothing shows up on the tv screen.

So would this point at a faulty USB port AND screen, this seems strange they are both faulty? Or is there something else that will stop visual output?

Any pointers would be great.

Thanks

 

[lpoolm]

So I made progress. I swapped the motherboard into another shell to test the screen, it would not turn on at all?
I thought great, what have I done so swapped it back turned it on and it started?
At first it would not recognise the right joycon but gave it a little clean and even though it doesn't show the onscreen graphic of it connecting it does and I could set the switch up so this is the first issue.

It loads and comes up with an error message about the game card but on closer look the cartridge is damaged so will look at swapping that so that should be an easy fix.

I still have the problem of it not charging or connecting to the tv so is this pointing at a faulty usb c port?
It looks ok internally but have attached a pic for people to tell me is it a stock usb or has it had a change?
Whoever had it before me had did some work around this area as the water damage sticker is faded so not sure if they changed the port or the chip next to the battery connector?

Any advice would be brilliant thanks, I hate swapping usb ports but will do if people think this is the issue.

 

[Alfixes]

Hi, yes defo had change. I'd start there by changing port as many rip pads underneath (not exposed ones) and then cover it back up. If you have an eye glass or microscope you will see deformed plastic on it.
I've done the same thing as you and bought faulty switch lol
Port on mine wasn't soldered solid plus many shorts which I'm working through. I now have 0.46a and battery charging with nothing else plugged in. However, maxx77621 and other shorts are there

 

[lpoolm]

Hi, yes defo had change. I'd start there by changing port as many rip pads underneath (not exposed ones) and then cover it back up. If you have an eye glass or microscope you will see deformed plastic on it.
I've done the same thing as you and bought faulty switch lol
Port on mine wasn't soldered solid plus many shorts which I'm working through. I now have 0.46a and battery charging with nothing else plugged in. However, maxx77621 and other shorts are there

Thanks I hate changing usb ports but if it needs to be done!
I'm just hoping no pads are missing!!

 

[Alfixes]

Also try ablong video ic on the back P13 I think (mouser). it is close to the port check cap next to it for short.
With port you need alot of heat, protect surround with capton tape. Actually try charger both ways first, then if you have multimeter check voltage reaching inside on exposed pins. There are few videos on YouTube on few simpler issues but not all.

 

[CHTechRepair]

Thanks I hate changing usb ports but if it needs to be done!
I'm just hoping no pads are missing!!

All signs point to the port or P13, if the console powers but won't display port out these are the places responsible. You might also check the components near P13, though I've only seen them have an issue once as the result of a bent port.

Hi, yes defo had change. I'd start there by changing port as many rip pads underneath (not exposed ones) and then cover it back up. If you have an eye glass or microscope you will see deformed plastic on it.
I've done the same thing as you and bought faulty switch lol
Port on mine wasn't soldered solid plus many shorts which I'm working through. I now have 0.46a and battery charging with nothing else plugged in. However, maxx77621 and other shorts are there

Your symptoms indicate successful battery charging but with no image or fast charging we can assume firmware isn't starting. How do we confirm this? Plug device in with no battery. The device should pull up to 0.10a in some cases. When GPU and firmware are started, this will go to 0.00a when logic has determined there is no battery to charge. Does your board stay at 0.06-0.10a? Your board is brain dead. I'm assuming you have an HAC-CPU model board and not HAD-CPU. The +max ICs by the GPU are PMICs for ultra-low voltage rails. As a result their resistance is very low and your normal continuity test will ring out. These ICs get battery voltage and put out roughly 0.8v to three separate capacitors and inductors seemingly for the GPU, maybe someday we'll get a schematic. These rails can range anywhere from 60ohm to 240ohm to ground. A diode mode reading is the best way to see if you truly have a short here. If you do and you have the skill, you can replace and likely have a working console. Word of caution: speaker connectors melt easy, and edges of boards take a lot of heat. Take it off with low melt solder first, or prepare to hardwire right speaker. I've seen several GPUs short on the 3.3v logic power rail, I assume this will be a signature failure of these consoles in the long run on top of the many many others. You can confirm this isn't the case on the large capacitor above P13, do a diode measurement the rail is usually above 0.300 lower is bad news. Keep in mind this rail goes everywhere, GPU may not be the source of the short but merely is affected by it. P13 can short this and so can M92. Voltage injection + alcohol/thermal camera is the only way to hunt the short and blame GPU. If you don't have any true short, your next target is the main PMIC (also +max) located on the same side of the board as P13. This supplies both the 3.3v rail that goes to most logic chips and GPU and many low voltage GPU / RAM rails. Unfortunately this guy doesn't like to go short so confirming failure is difficult. Someday when I have time I'll write down known good diode values and make my life easier. In most cases simply replacing the chip is the best course of action, but you will need a lot of patience and skill to achieve this. Once this is replaced well, the last piece of the puzzle is the GPU / RAM which can also be replaced with enough skill but at that point a new board will make you pull your hair out less.

Good luck to both of you in fixing!

 

[Alfixes]

Your symptoms indicate successful battery charging but with no image or fast charging we can assume firmware isn't starting. How do we confirm this? Plug device in with no battery. The device should pull up to 0.10a in some cases. When GPU and firmware are started, this will go to 0.00a when logic has determined there is no battery to charge. Does your board stay at 0.06-0.10a? Your board is brain dead. I'm assuming you have an HAC-CPU model board and not HAD-CPU. The +max ICs by the GPU are PMICs for ultra-low voltage rails. As a result their resistance is very low and your normal continuity test will ring out. These ICs get battery voltage and put out roughly 0.8v to three separate capacitors and inductors seemingly for the GPU, maybe someday we'll get a schematic. These rails can range anywhere from 60ohm to 240ohm to ground. A diode mode reading is the best way to see if you truly have a short here. If you do and you have the skill, you can replace and likely have a working console. Word of caution: speaker connectors melt easy, and edges of boards take a lot of heat. Take it off with low melt solder first, or prepare to hardwire right speaker. I've seen several GPUs short on the 3.3v logic power rail, I assume this will be a signature failure of these consoles in the long run on top of the many many others. You can confirm this isn't the case on the large capacitor above P13, do a diode measurement the rail is usually above 0.300 lower is bad news. Keep in mind this rail goes everywhere, GPU may not be the source of the short but merely is affected by it. P13 can short this and so can M92. Voltage injection + alcohol/thermal camera is the only way to hunt the short and blame GPU. If you don't have any true short, your next target is the main PMIC (also +max) located on the same side of the board as P13. This supplies both the 3.3v rail that goes to most logic chips and GPU and many low voltage GPU / RAM rails. Unfortunately this guy doesn't like to go short so confirming failure is difficult. Someday when I have time I'll write down known good diode values and make my life easier. In most cases simply replacing the chip is the best course of action, but you will need a lot of patience and skill to achieve this. Once this is replaced well, the last piece of the puzzle is the GPU / RAM which can also be replaced with enough skill but at that point a new board will make you pull your hair out less.

Good luck to both of you in fixing![/QUOTE]
First of all thank you for taking your time and replying in detail. Really appreciate it! I'm technician and fully capable changing everything on the board (with obvious difficulty) however it is going to get expensive. I now gone back to 0A as accidentally shorted pins on mosfet above m96. I will try to remove p13first then maxx77621 and see if some shorts will be releaved.
I cant believe no one leaked schematics for this. I am using this as learning curve and was hoping I can get my working switch dock as kids can't play together on small screen.
In your experience if I have few shorts under nvidia can it be short on capacitor or doest it originates somewhere else? Maybe both maxx77621?
Also as I'm new to this forum can you contact members directly?
Thank you for your help

 

[CHTechRepair]

First of all thank you for taking your time and replying in detail. Really appreciate it! I'm technician and fully capable changing everything on the board (with obvious difficulty) however it is going to get expensive. I now gone back to 0A as accidentally shorted pins on mosfet above m96. I will try to remove p13first then maxx77621 and see if some shorts will be releaved.
I cant believe no one leaked schematics for this. I am using this as learning curve and was hoping I can get my working switch dock as kids can't play together on small screen.
In your experience if I have few shorts under nvidia can it be short on capacitor or doest it originates somewhere else? Maybe both maxx77621?
Also as I'm new to this forum can you contact members directly?
Thank you for your help

Any shorts you are measuring under CPU or RAM are not likely to be true shorts. There are many very low impedance rails to the CPU. Measure at ICs, always assume CPU is good until you can confirm it is not.

 

[Alfixes]

Hi, did you managed to find a solution? I have one switch which outputs to dock but not in handheld mode, interested to see if you fixed yours? Thanks