(347) 552-2258 [email protected]

820-00928-A Wont boot to OSX (random shutdown)

ALB-Repairs

ALB-Repairs

Member
Hi
Odd one, one of my refurb machines, 15" touchbar that had some liquid damage.
Not really bad, Gave it an inspection and ultrasonic as it wasn't booting properly, It seems to be getting worse and worse but it gets the loading bar and then just shuts down.
Does the same on Apple Diagnostics and safe mode. Im a bit stuck as i havent seen this issue before.
Anyone seen this behaviour?

Thankfully i have testing parts and a known good shell that ive tested this in, It is not to do with peripherals. Ive also tested it on an external drive and found the same issue.
 
D

dukefawks

Administrator
Could be absolutely anything, corrosion under some chip, corroded resistor/trace. Common is a corroded pad under a QFP chip.
 
ALB-Repairs

ALB-Repairs

Member
dukefawks said:
Could be absolutely anything, corrosion under some chip, corroded resistor/trace. Common is a corroded pad under a QFP chip.
Click to expand...

Ive cleaned up the corroded areas and it has made no change. Spent a long time on inspection on this board. I will try a clean ME bios, although its not been messed with before sometimes ive seen bios corruption due to liquid damage.

Thanks
 
ALB-Repairs

ALB-Repairs

Member
Tried a clean ME region with no changes.
Tried a known good shell with no changes.
If lifeboat jumper is removed it sits on a flashing folder with no shutdown
Replaced both CPU and GPU buck regulators as that was the coroded area.
Still not getting any further sadly
 
ALB-Repairs

ALB-Repairs

Member
2informaticos said:
If no important data on SSD, try new instalation...

Try first USB OSX.
Click to expand...

Will not boot to USB OSX.
It will not boot to USB installer.
It will not run diagnostics.
every time i try anything it will shut down and restart.
Sometimes it will not post. When it fails to post we have all power rails however the GPU voltage on LA350 will stick at 0.9V and not drop to 0.8v.
Also no safe mode either, or single user/verbose mode
 
Last edited:
You must log in or register to reply here.
Top