Hacking Question Will a bricked Switch boot into RCM ?

[WadsRUs]

Okay, will swap out the chip (possibly tomorrow) and report back.

Yes, it's an old Switch so RCM should work okay.

Thanks for your help and advice so far.

 

[mattytrog]

Okay, will swap out the chip (possibly tomorrow) and report back.

Yes, it's an old Switch so RCM should work okay.

Thanks for your help and advice so far.

The bq24193 can prevent boot, can make a NAND corrupt, all sorts. A fully charged battery won't make any difference if it is misfiring.

It sends and receives commands via I2C. Therefore if bad, no power will go through it.

But if you are not even getting RCM (test with battery disconnected too) then m92t36 is prime suspect.

Check pin 5 VCC-IN on the m92t36 as I said in my last post. If between 3v and 6v, with charger plugged in, the power detector in the chip and internal power to the chip is working and more than likely OK

 

[SentaiBrad]

Reading through has been extremely fascinating. Now I'm sitting here wondering "Will it power on" like a bad TV Drama.

 

[Benjay]

Reading through has been extremely fascinating. Now I'm sitting here wondering "Will it power on" like a bad TV Drama.

Same here ^^

 

[WadsRUs]

The bq24193 can prevent boot, can make a NAND corrupt, all sorts. A fully charged battery won't make any difference if it is misfiring.

It sends and receives commands via I2C. Therefore if bad, no power will go through it.

But if you are not even getting RCM (test with battery disconnected too) then m92t36 is prime suspect.

Check pin 5 VCC-IN on the m92t36 as I said in my last post. If between 3v and 6v, with charger plugged in, the power detector in the chip and internal power to the chip is working and more than likely OK

The bq24193 is part of the battery assembly, correct?

I did try another (known good) battery but no luck therefore, hopefully, it's the m92t36

Is there a pinout/datasheet for the m92t36 online?

--------------------- MERGED ---------------------------

Well, tried removing the m92t36 but for some reason it won't desolder. I know it has a large ground pad underneath but my hot air rework station hasn't let me down before with all kinds of jobs. Perhaps the m92t36 has failed so spectacularly that it's welded itself to the board!

 

[mattytrog]

The bq24193 is part of the battery assembly, correct?

I did try another (known good) battery but no luck therefore, hopefully, it's the m92t36

Is there a pinout/datasheet for the m92t36 online?

--------------------- MERGED ---------------------------

Well, tried removing the m92t36 but for some reason it won't desolder. I know it has a large ground pad underneath but my hot air rework station hasn't let me down before with all kinds of jobs. Perhaps the m92t36 has failed so spectacularly that it's welded itself to the board!

It does come off. 330 degrees. Put some no clean flux around it.

The bq24193 is the first chip you see next to the battery connector.

Datasheets for both are online

 

[WadsRUs]

It does come off. 330 degrees. Put some no clean flux around it.

The bq24193 is the first chip you see next to the battery connector.

Datasheets for both are online

Thanks, I'll try again later.

Something that I also just discovered about the m92t36 - a faulty one can also be responsible for a lack of HDMI output when the Switch is docked. Discovered that quite by accident when looking around for info on the chip and found the information on this repair site -

https://www.tfix.co.uk/product/repa...nintendo-switch-no-hdmi-output-m92t36-repair/

 

[mattytrog]

Thanks, I'll try again later.

Something that I also just discovered about the m92t36 - a faulty one can also be responsible for a lack of HDMI output when the Switch is docked. Discovered that quite by accident when looking around for info on the chip and found the information on this repair site -

https://www.tfix.co.uk/product/repa...nintendo-switch-no-hdmi-output-m92t36-repair/

https://www.rohm.co.jp/datasheet/BM92A30MWV/bm92a30mwv-e

Close enough datasheet for m92t36.

A million things could cause no hdmi.

The m92t36 is responsible for sorting the differing voltage levels you get from different chargers/docks. Some go up to 15v+.

But no hdmi could be the multiplexer / matrix switch whatever you want to call it...

Could even be a broken USB port. Bell it out with your meter.

 

[WadsRUs]

Thanks.

Try as I might this m92t36 will not come off - I see from doing some reading that other people also struggle badly with QFN chips.

How long do you normally find that you need to heat it for before it comes off at 330 degrees? The central ground pad on the large ground plane is of course the problem.

BTW, the USB port is fine.

 

[mattytrog]

Thanks.

Try as I might this m92t36 will not come off - I see from doing some reading that other people also struggle badly with QFN chips.

How long do you normally find that you need to heat it for before it comes off at 330 degrees? The central ground pad on the large ground plane is of course the problem.

BTW, the USB port is fine.

Sometimes I have to up the temp to 380. Very low flow rate of air. Persevere. It will come off.

Just don`t get it that hot you start blistering the mask.

 

[WadsRUs]

Noted, thanks.

I'll try 380, but how many minutes can I do this for without damaging anything?

 

[mattytrog]

Noted, thanks.

I'll try 380, but how many minutes can I do this for without damaging anything?

Observation is key. I like using flux as an approximate indicator. Then the flux is smoking, its hot enough. Normally.Would be a good idea to Kapton around the m92t36. As close as you can.

Hold the nozzle about 15mm - 20mm from the chip at the most. Closer if poss.

 

[WadsRUs]

Still no luck I'm afraid, even with heating it for a few minutes.

Didn't think such a small chip would put up such a fight.

I'm stumped.

 

[mattytrog]

Still no luck I'm afraid, even with heating it for a few minutes.

Didn't think such a small chip would put up such a fight.

I'm stumped.

There is nothing else holding it on. It just isnt hot enough.

Hotter. Needs hotter!!!

What have you got to lose? Its fucked as it stands anyway.

 

[WadsRUs]

As you say, nothing to lose - I'll keep at it (maybe have another go soon or try again tomorrow).

I'll report my findings here.

Thanks for your help.

 

[WadsRUs]

Finally managed to desolder it ........... along with a few adjacent caps and resistors. Ooops. (my hand slipped as I was removing the chip).

I have all of those parts but now realise that I need a microscope in order to re-attach them!

Hmmm, I've always wanted an excuse to buy a decent microscope .......... if only I had the money!

 

[mattytrog]

Finally managed to desolder it ........... along with a few adjacent caps and resistors. Ooops. (my hand slipped as I was removing the chip).

I have all of those parts but now realise that I need a microscope in order to re-attach them!

Hmmm, I've always wanted an excuse to buy a decent microscope .......... if only I had the money!

A decent magnifier should do it. Good app on Android called magnifier camera. Got me out of a hole before doing 0201 size stuff (the smallest around the m92t36)

Replace chip first. Clean all that lead-free shit off there. Good once over with a cotton bud (qtip for you lot across the pond) with some IPA. Put some leaded on there when you refit.

 

[WadsRUs]

I'll look up that magnifier camera app for Android, sounds very promising - does it come with a spare hand for holding the phone while using the other hands for holding the hot air tool and tweezers? Seriously though, i'm sure I can find a way to mount it to something. How close does it need to be to get a good magnification?

I already have a desktop magnifier but that only magnifies by about 2 times which isn't enough.

I have a small handheld magnifier too (40x) but it needs to get so close to whatever it's looking at that I couldn't use it and solder at the same time - it would just get in the way.

Noted re attaching the new chip first, cleaning up the old solder, etc.

As an aside, I often watch Louis Rossmann's YouTube channel and now I have an even better appreciation of what he does on the Apple boards, at least he has a decent microscope though!

 

[mattytrog]

I'll look up that magnifier camera app for Android, sounds very promising - does it come with a spare hand for holding the phone while using the other hands for holding the hot air tool and tweezers? Seriously though, i'm sure I can find a way to mount it to something. How close does it need to be to get a good magnification?

I already have a desktop magnifier but that only magnifies by about 2 times which isn't enough.

I have a small handheld magnifier too (40x) but it needs to get so close to whatever it's looking at that I couldn't use it and solder at the same time - it would just get in the way.

Noted re attaching the new chip first, cleaning up the old solder, etc.

If you prep right, just place the chip on there. Drown the little bastard in no clean flux... Hold it down. You will find the chip "wants" to line itself up to the pads if hot enough.

To get the components back on, solder them to a tip of a sewing needle or Something stiff,awg 30 first. Then just touch the other end on to a pad. Touch iron on your needle, flow other end. May put a quick video demo up when I can.

 

[WadsRUs]

Some good tips there, thanks!

I've been soldering for many years, even done a fair amount of surface mount work, but not on such a device as the Switch where the parts are pretty miniscule compared to what I'm used to.

I tried the Android magnifier camera, couldn't get as much detail as I'd hoped so have ordered a headband LED magnifier - the standard lenses can go up to 3.5x but two can be stacked to increases magnification. I should have it in a couple of days so will continue the work then.