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820-00239 Won't post with battery connected, power button not working

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tcampbell34

Member
Hello. I got an 820-00239 that was heavily liquid damaged on the U32/3100 side of the board. The board would turn on to flashing folder icon still even with this damage. I had to replace J3300, J4402, J6200 and Q3100 due to corrosion. The board now boots fine on all 4 ports and the touch bar is working. I can boot into the OS with out the battery flex cable connected and the computer works fine, except for the power button was not working. If I connect the battery and charger, I hear the charger dong sound and CPU_VCORE is at 1v, but then it drops to 0v a few seconds after the dong sound and the board does not turn on. It seems to try to start and then shuts down and gets stuck in S5 state for some reason. Its taking 2.2 amps when in this state so the battery appears to still be charging. I tried the board in another topcase, which has a good battery and power button, but I still have the same issue with the battery and power button. When I press the power button, SMC_ONOFF_L does drop to 0v, but PM_PWRBTN_L stays at 3.3v. I know this usually means its an SMC issue, so I replaced the SMC with one from a donor but still have the same issues, so I don't think its an SMC issue.
 
2informaticos

2informaticos

Administrator
Staff member
The power button doesn't work when charger and battery are both connected?
But works on charger alone?

Check ohm resistance over C7020/23.
Do you get 3V3_G3H and PPBUS_G3H with battery alone?
Also post exact PPBUS_G3H voltage with charger alone.

You can try changing Q7065, just in case.
 
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tcampbell34

Member
Power button does not work at all, no matter what power source I have connected.

C7020/23 are both 2.9Ohms
PP3V3_G3H is 3.39v and PPBUS is 11.46v with battery alone.
PPBUS is 13.03v with just charger connected.

I will try and change Q7065 and report back.
 
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tcampbell34

Member
I was going to replace Q7065 but decided to test the board with another battery that I had out of the topcase. So I just had the board on the desk with the battery and charger connected, and a USB drive to check for USB activity and the board works fine in this case. I figured out it only does not boot with the battery connected, if the screen is also connected. I have tried 2 different screens and have the same issue with both, so I don't think its the screen itself that is causing the issue.
 
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tcampbell34

Member
Yes I can boot to the OS with everything connected except the internal screen. Battery charges and works fine also. It works fine using external monitor and diagnostic only reports an issue with the display, since its not connected. I can boot with the internal screen connected, but only if the battery is disconnected.
 
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tcampbell34

Member
I tried that but same thing still. It makes the dong sound and the screen backlight turns on for a second and then turns off, and then board gets stuck in S5 state.
 
2informaticos

2informaticos

Administrator
Staff member
So you've tried with different known good batteries and LCD assemblies also?

Does it boot in SMC bypass, or safe mode, with screen and battery connected?
 
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tcampbell34

Member
Yes I have tried with 3 different batteries and 3 LCD assemblies and it does the same thing with all of them. I tried to start it in SMC bypass mode by holding down the power button and then connecting the charger, and it actually turns on with both the screen and battery connected, but its not actually in SMC bypass mode. The fans are not running and HWmonitor is still reporting all the system temps, which it normally does not in SMC bypass mode. The power button is still not working when booted in this mode, so I'm sure that's why it does not go into SMC bypass mode, by yet it still boots. If I turn if off and try and turn it back on, it does the same thing again where it boots, and then shuts down. I noticed also that it will not turn on automatically when you open the lid. It will only start when connecting the charger. It will also shut down when trying to start in Safe mode with battery and LCD connected.
 
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tcampbell34

Member
Yep that was it. I checked and SMC_LID and SMC_LID_RIGHT were 3.4v, but SMC_LID_LEFT was 0v. I checked J5250 and found some corrosion there, that I did not see before. I replaced the hall sensor and SMC_LID_LEFT is now 3.4v also, and all the other issues seems to be fixed now. The power button works to turn the the computer on and off now, but Touch ID is failing. Says "Unable to complete Touch ID enrollment. Please go back and try again".
 
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tcampbell34

Member
I am not really concerned with the touch ID issue at this point, but I found a new issue. I went to install Big sur via Recovery mode (Option + Command + R) and it will load for about 5 minutes and then it displays error -5101. I cannot get into recovery mode at all. I then booted into a Big sur installer on an external SSD and that works and I erased the drive and started the installation. It goes to the black screen with apple logo and says about 29 minutes remaining and then reboots after like a minute or two, and then it will not post. CPU_VCORE stays at 1v and does not drop like it should and there is no caps lock reaction. The only way I am able to get it to post again is to install a Clean ME Bios. I have tried a fresh install of Catalina also and it does the same thing. The only way I seem to be able to get an OS on the internal drive is by cloning the drive in Disk Utility from another OS I have on an external drive. Once the clone is complete, I can boot to that and the computer seems to work fine. Any idea what could cause this?
 
2informaticos

2informaticos

Administrator
Staff member
I think about BIOS corruption in the install process; as you said needed to clean ME to make it starts again.

If you got it works cloning the SSD, test it several days.
 
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tcampbell34

Member
It definitely is corrupting the BIOS somehow during the installation. I tried installing Mojave, Catalina, and Big Sur on it, and it corrupts the BIOS every time and I have to re flash it. I was able to do a fresh install of High Sierra though without it corrupting the BIOS. I can clone Big Sur onto the drive and boot to it, but if you try to do any kind of system update, the BIOS will get corrupted and the computer wont turn on. I cloned Big Sur v11.1 and tried to do an update from the OS to v11.2.1 and it corrupted the BIOS again. I found something online that mentions the computer needed to be on the right firmware version in order to access recovery mode and update. If I go to System information > Hardware, it says the System firmware version was like 139 or something like that, which seems very low. The two other Macbooks I have (A1707, A1708) that are on Big Sur have System Firmware version 429.80.1.0.0. I found another BIOS file online for this model and installed it and it updated the System Firmware to 267.0.0.0.0, and now I can boot into recovery mode without the -5101 error like I was getting before, but it still corrupts the BIOS when trying to install Big Sur. I think what I need is a working BIOS from the same model, that has already been updated to the 429.80.1.0.0 system firmware. You wouldn't happen to have a recent BIOS backup from a 2016 A1706 with Big Sur already installed on it?
 
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