820-3330 Shutting Off Intermittently

brunomotter

Member
Hello. Got this board here that shuts itself down when stressed. I thought initially it was bad battery because it was indeed bad. So I replaced it three times and same thing. Decided putting in an original battery that's working perfectly on another machine and problem persists, so I discarded battery issue. I then started digging for the problem. As lots of these boards have GPU issues, I decided to flash GMUX with DOSDUDE method, but problem persists. ASD detects no issues with any sensors. The machine has problems with power connected and just on battery. Using genuine(bought directly from apple) 85W magsafe charger, so charger is not the issue here also. A strange thing I noticed is that when running on battery, if I launch coconut battery, even with GPU disabled, it gives some peaks of more than 60W of consumption, probably an error on sensor readings... I verified R7020/21 and R7050/51 and they read ok. Replaced U7000, Q7030/35 and Q7080 just in case. Same issue, although read consumption lowered in average after replacing them, but still having random shut downs, also no matter if original battery or replacement one and no matter if it's on charger or on battery. I'm going nuts with this machine, it's a rabbit hole to hell...
 

brunomotter

Member
I removed the resistors, same problem. In safe mode the problem appears to not occur, probably because of the lack of video drivers, so the machine does not draw much power.
 

2informaticos

Administrator
Staff member
Did you test with original battery from A1286/2012 for sure?
I saw many weird issues on this model with new chinese batteries.
 

2informaticos

Administrator
Staff member
These machines have also strange behavior if no good battery connected.

Instal gfxcardstatus and test the machine with iGPU and dGPU also.
See if only fails with discrete GPU enabled.
 

2informaticos

Administrator
Staff member
Never tried that method.
Hardware mod suppose more work, but may be the solution of this problem.
Just try it, if have time...
 

brunomotter

Member
Testing it again now... Now HWMONITOR is telling me CPU RAIL (CPU Total) is consuming a whopping 65W(!!!!!). Think maybe I found where the problem is, but how to solve?
 
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