Intermitten SD Card power supply loss

Hi there, my switch started to become an intermitten problem where the SD Card suddenly stops working
It has a sx core and therefore without a working sd card the console is kinda useless (still boots into ofw when the sd detect line is low, but not into safe emunand)

After replacing the SD Card reader and soldering on wires directly from reader to mainboard i noticed that the issue still appears

Hekate detects that the SD Card “is removed” as soon as a flick against the mainboard where the wireless chipset shield is - this also happened with the original reader

What i also noticed is that the power line for the sd card goes from initially 3.3v to 0.6v - this also happens when it is at a stable 3.3v and i flick the mainboard

Where do the 3.3v go trough? i expect there to be a cold solder joint which is expected from the quality of the mainboard

There is a GPIO line that notifies the CPU that a card is present or not. Its possible there is a problem with that line.

Could the problem be with the SD card?

The foam pad is also pretty critical for keeping pressure on the connector.

3v3 supplies the P13, M92 and BQ chips and is generated by a regulator just above the audio chipset. Possible you could have an intermittent issue with one of those chips, although you’d probably see bigger issues than just a dropped SD card.

The SD card works fine, sd detect line is @ 1v8 when the card is removed (and sd voltage is @ 0.6v) so there is no issue there since i would expect 3.3v with inserted card and 0v with removed.
(also 0.6v doesn’t make any sense, its too low for a card to work)

after putting the card back into the broken system the sdcard voltage stays at 0v, so i expect that some part on the rail that produces the voltage is half dead

i also did this: “…soldering on wires directly from reader to mainboard…” so i can say with confidence that there is no connection issue between sd card and mainboard

the voltage rail for the sd card comes from the multi rail step down converter on the backside, 3.3v on the “usbc chips” is perfectly fine

i’ll check if the maxim chip gives out 0.6v on one point and if not i’ll check the parts which look like a mosfet and transistor on the bottom side (reflowing them didn’t help)

worst case is that i have to replace the step down converter chip or place a wire if a via somehow broke (which would be really wierd)

while the board wasn’t screwed in the console worked perfectly fine so hopefully its just a broken solderjoint