Hi everyone, I have a switch with a damaged charging port. After replacing it I could see it drew 5v at 0,47 amps for about a minute, then it went to 0,1. After opening it up again I noticed a short on the 3V power line (the big cap beneath P13USB among other places). I removed the P13USB, MT92 and EMMC but the short was still there. I injected 2A with my PSU but nothing got warm on the thermal camera. Does anyone know what this could be? Thanks!
What’s is the resistance to ground on this shorted rail? (3V3PDR)
Off the top of my head Wifi IC VIN is this rail. SoC has a connection to this rail and of course the ENXX IC which produces this rail, Can’t think what else I’d have to go over my documentation, but there was a topic on here which I replied in which I went over all possible locations to check and aside from the ones mentioned it turned out to be SoC at fault.
It’s 0ohm so a dead short. There are a few capacitors all around the board that are shorted so I assume this is all the same rail. What is SoC?
Yeah probably, unless there is some other rail/line shorted by chance
If P13 and M92 is removed, and you confirm it’s not the EMMC module or Wifi IC or ENXX IC, then chances are high it’s SoC which is the Tegra,- largest IC on the board as dead short would make a considerable amount of heat elsewhere, though you could try increasing your current limit here.
I just removed the 2 IC’s and the short was still there. I guess it’s the SoC then. This is not fixable?
not conclusively, also the other ICs I mentioned above…
Also forgot the main max PMIC which is also connected to this rail if I remember right.
But given you not getting any heat when connected to your bench PSU then SoC is more likely as it can sink substantially more heat than elsewhere.
If it is the SoC at fault, it can be on a very slim chance be junk underneath and a reball can sometimes on an even slimmer chance resolve, but typically wouldn’t expect a dead short in these cases