Alex97Lewis
Member
Hi, first time posting here so bear with any details that are lacking. Trying my best to resolve issues with this board but going absolutely nowhere.
Not much history to go by with this board, apart from seeing minor liquid damage across J1800, not much there nor any of it bridging across the pins. So cleaned this up.
The device wouldn't boot up whatsoever when I first got it, attempted SMC/PRAM reset but made no difference. Found a very small bit of liquid on U1900 which was replaced. After that it actually booted with a mouse connected and lit up.
Gave it back to the customer yesterday and the issue happened again, no life. So looking at it all day today, there's 1.79V on CPU VCore, but the cpu doesn't get hot at all. Checked all state rails and of course were all on fine, just nothing else, no display or backlight, no USB mouse light activity. Powering it currently with a bench PSU and every so often when turning off then back on the psu, it will sometimes actually get past post and start to boot, sometimes all the way into the OS and will stay fine, other times it'll fluctuate between pulling 0.8A down to 0.02a. Right now it's got full fan spin and pulling 0.05a with no display, and cold cpu. These CPU temp measurements are with heatsink off by the way.
All memory power rails are turning on fine just checked that in case. Just so confusing to how this board sometimes powers up (one in every 6 or so attempts).
Any idea on what this may be? Haven't really seen anything on the forum that describes a similar issue to what I've got. Been thinking of trying a different spi rom just to see if that fixes anything, I'm just doubting it because it does sometimes boot.
Thank you!
Edit: I have tried SMC bypass before that is requested to try. Still has the same issue.
Not much history to go by with this board, apart from seeing minor liquid damage across J1800, not much there nor any of it bridging across the pins. So cleaned this up.
The device wouldn't boot up whatsoever when I first got it, attempted SMC/PRAM reset but made no difference. Found a very small bit of liquid on U1900 which was replaced. After that it actually booted with a mouse connected and lit up.
Gave it back to the customer yesterday and the issue happened again, no life. So looking at it all day today, there's 1.79V on CPU VCore, but the cpu doesn't get hot at all. Checked all state rails and of course were all on fine, just nothing else, no display or backlight, no USB mouse light activity. Powering it currently with a bench PSU and every so often when turning off then back on the psu, it will sometimes actually get past post and start to boot, sometimes all the way into the OS and will stay fine, other times it'll fluctuate between pulling 0.8A down to 0.02a. Right now it's got full fan spin and pulling 0.05a with no display, and cold cpu. These CPU temp measurements are with heatsink off by the way.
All memory power rails are turning on fine just checked that in case. Just so confusing to how this board sometimes powers up (one in every 6 or so attempts).
Any idea on what this may be? Haven't really seen anything on the forum that describes a similar issue to what I've got. Been thinking of trying a different spi rom just to see if that fixes anything, I'm just doubting it because it does sometimes boot.
Thank you!
Edit: I have tried SMC bypass before that is requested to try. Still has the same issue.
