Switch V2 With HWfly Green led blinking, no boot

[Nikaia-Repair]

Hey guys,

I've installed a lot of HWfly these past years, but i had a first time issue today lol

I just finished soldering the ribbon, put the nand at it's place, i was just looking for cissors to cut the metal plate, then i heard the switch fall...
It booted in "No SD card" but then when i turned it off, I realized the connector for the nand, on the HWlfy Side, was broken.
So I changed the Hwfly, and then the Led began to do a thing i've never seen before, which is blue for 3 secs, then light green with an irregular blinking, then nothing. I've tried everything, resoldering, etc, but nothing worked. I've then taken off the HWlfy Chip, to see if it still boots in OFW, but nothing. No backlight, nothing...
I can't access the "No SD card screen, nor the original FW boot now. I don't know whete to begin... The switch seems to charge normally, but doesn't go more than 0.15A on the 15V charger.
Do you think, such as the M92 or another one could have died? I tested the capacitors around it, none seems shorted...
I know it's hard to give an answer, but what would you do if you were me?

Thanks by advance

 

[thesjaakspoiler]

First start off with a good visual inspection around the CPU shield and other areas where you were working on.
If your solder work looks good, then just leave it.
Measure the points with a multimeter in diode mode and continutiy (just to be sure there isn't short to ground.

Check out all these pages to see if all your power lines are present.
https://www.retrosix.wiki/first-stage-boot-short-checks
There are also some pictures here on the forum for what to expect around the M92.

Green blinking error code means that it cannot access the files on the SD card.

I would also check if the LCD connector is seated properly.
I sometimes get Switches for repair where the LCD connector is not seated properly or the flat cable has tears.

 

[Nikaia-Repair]

First start off with a good visual inspection around the CPU shield and other areas where you were working on.
If your solder work looks good, then just leave it.
Measure the points with a multimeter in diode mode and continutiy (just to be sure there isn't short to ground.

Check out all these pages to see if all your power lines are present.
https://www.retrosix.wiki/first-stage-boot-short-checks
There are also some pictures here on the forum for what to expect around the M92.

Green blinking error code means that it cannot access the files on the SD card.

I would also check if the LCD connector is seated properly.
I sometimes get Switches for repair where the LCD connector is not seated properly or the flat cable has tears.

Thanks for the answer man. Very useful website, I didn't know about it, it'll be very helpful lol.

I've been up to the powering on as I had no shorts when putting the 4.2V.
I'm stuck at 100mA, i never get past that value, so I guess it's a stuck 1st stage boot.

So I checked the MAX77620 Voltage Rails, while comparing to a Healthy V2 Switch (because they said they measured on a V1 so I wanted to be sure) and here are my results :

So the signal that shows an error looks to be the VDD_CPU_1V1. It has the normal value on the healthy motherboard, and 50mA on the "bad" motherboard.

I also tested the 3.3V Rail Injecting 1V and i have almost 0mA. Which is not specially a problem according to the website, and I have the same on the healthy motherboard.

From what I've seen on this website, as it's a 1st stage boot issue, I can't look for anything else for now, as the following things to do are linked to 2nd stage boot... Unfortunately, they don't say what could be the issue with that low current output on VDD_CPU_1V1.... or if they do, I didn't find where it is lol.

If anyone has an idea, that would help a lot !

Thanks guys

Post automatically merged: Sep 18, 2025

Hey guys, sorry for the UP but I might try reballing a new MAX77620 to try and change it. Do you think it's the good thing to do?
I'm lost here, I never had these kinds of boot issues lol
Any help would be really appreciated.
Thanks by advance guys