820-00281-a A1707

Mac Tech

Member
I have this machine that takes time to turn on, I already reprogrammed bios and format but still the problem continues.

When the machine is in sleep and you press any key to bring up the image, it freezes and reboots, "displaying a screen in three languages and Chinese letters"

Inspecting the area of U4200 it looks good but there is a voltage that I am missing from the BUCK "L4202" I have that voltage in 453mv.

The other Bucks show their correct voltages, I don't have another plate to see if that voltage should be present or is.
 

2informaticos

Administrator
Staff member
Did you check that voltage at C4208?

Do you mean sleep by closing lid?
Check U5255 voltages, when comes back from sleep (open lid).
 

Mac Tech

Member
Did you check that voltage at C4208?

R: that's right, I just checked with another board and it has the same voltage at boot time.

Do you mean sleeping with the lid closed?

R: that's right, the machine takes time to turn on, once it is in the user window, after a while it goes to sleep, when it starts again it freezes and restarts.

Check U5255 voltages, when comes back from sleep (open lid).
 

Mac Tech

Member
the fans rotate normally, remove the j9600 and use external usb with catalina, "something curious" when it starts it does not show the apple but the progress bar appears. It does not enter the system externally but to the recovery mode, it does not have a boot security utility.
 

Mac Tech

Member
yes brother, also reprogram bios and still the same.

The recovery mode loads quickly without problem, the problem is when starting the system and when you are going to turn it off, it also takes time.
 

Mac Tech

Member
place the complete motherboard in another case, to rule out that it was some peripheral. but equal. The same problem
 

Mac Tech

Member
I passed the diagnostic mode but it did not throw any error code. Activity monitor does not show anything abnormal.

What I have noticed is that when the "about this mac" window is opened, that WINDOW is frozen, but not the machine.

That is, I cannot close the window that shows information about the machine.
 
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