Ok so i have this mariko switch board that boots up normally (Playable) but doesn’t charge… no charging indicator, nothing at all, when plugged in using an original switch charger. upon checking the mobo, it has some short to ground capacitor near m92 chip, on pin 6 i believe.
but voltage is normal 3.3v when operaational. other near cap readings normal. another shorted cap is the one above P13, which commonly goes bad, when pin 6 is shorted as well. so already removed p13. but short still there, also those two caps above ENCXX ic. short as well. plus fuse above type c port, always get busted, even if already replaced it twice. type c port, also replaced twice… and doubled check everything. also removed fuel gauge and ENCxx IC, unfortunately short still exists, dont know where these shorted caps goes to or connected to what rail. please see attached images of the said components.
Hmmm, yeah I would usually suspect the P13, it does connect to other things though. I would check resistance to ground on all the main rails, and, though it is a different board revision you may be able to get some clues using this:
The shorted lines your highlighting is 3V3PDR, the USB fuse being open would point to a potential USB related fault and my money would be on the M92 IC being the cause of the 3V3PDR short to ground as it’s not uncommon for these faults to take it out.
You can narrow down the culprit by placing one probe on ground and the other at pin 6 of the M92 IC and measuring the resistance to ground then noting the reading, then do the same at the caps near the EN IC and then again at the P13 cap on this rail, whichever represents the lowest reading to ground is your culprit.
I would also carefully inspect your USB port for any bent pins or other signs of damage, maybe it’s fine and the failed fuse was as a result of a non Nintendo charger. If you’ve replaced the port on this board, then check it has continuity to it’s various destinations using a USBC breakout board, and after resolving your 3V3PDR short then check that none of the USB lines are crossed to one another for some reason.
already removed p13, m92 ic’s, two shorted caps above ENIC and big cap on top of p13
, remove shorted cap on pin 6. but yeah short still exist. will test usb c using breakout board after i sort out the short on 3v3pdr. hope its not an soc issue with this board.
I see, what resistance to ground do you measure on this 3V3PDR?
I’d also do as Insomniac suggested and measure your SYS rail (large 2R2 coil near BQ) and all other primary rails (surrounding the main PMIC on the rear) in case another rail is shorted and putting a subsequent fault on your 3V3PDR
ENXX IC, Wifi, EMMC and SoC and of course any bypass cap residing on this rail are all primary candidates for a 3V3PDR short to ground assuming no other main rail is shorted. Depending on the resistance of the short and provided no other rails are short then hooking up a bench PSU to the rail will likely expose the culprit.
thanks @Severence but looks like now im back to zero, after sorting out that rail maybe… cause now unit not booting up. cannot get 3.3v on either pin 5 or 6. already replaced M92 and BQ ic twice… still not getting 3.3v but 1.8v still present on little cap, below m92 ic. but the three caps above m92 ic, i’m not getting the usual 1.5v, 2.7v on it.
Hey,
If pin/pad 6 (3V3PDR) of M92 is a dead short to ground then you won’t get your 3.3V as it will either not be present or dragged down as a result which in turn will prevent the console from booting.
Do you have a bench PSU you can connect up to this shorted rail? if so I’d connect it up and set the voltage to1V with a current limit of initially 500mA and see what gets hot if anything to see if you can find the culprit, though as mentioned though it would be a good idea to check your other primary rails resistance to ground first.
Unfortunately using a Bench PSU not producing heat, even on a slightly higher amps… so out of curiosity… i removed both PMIC and the max77821 on this mariko board. and sadly short still there… 