-
For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.Subscribe Now
820-00850 not powering up
- Thread starter iClub
- Start date
Usually LDO rails.
And starts with full speed fan?
Possibly error with some SMC sensor.
Possibly error with some SMC sensor.
I didn't understand you; the machine only stays on 2s in SMC bypass?
I was thinking it works then...
I was thinking it works then...
Just turns on, or machine boots to OSX?
If yes, check SMC sensors level, pages 52-55.
If yes, check SMC sensors level, pages 52-55.
iClub
Member
machine boots to OSX.
And you get such oscillations when logged into OSX?
If you get USB activity, board boots.
You can also connect external monitor (not really needed).
Good enough to know that and check if signals are steady.
You can also connect external monitor (not really needed).
Good enough to know that and check if signals are steady.
But yo've said machine boots in SMC bypass mode; what happened?
iClub
Member
If I press power the machine turns on, but no image.
If I hold down power for 5 seconds it turns on, but it's not SMC bypass mode, because it doesn't stay on with the fan running.
Testing the board with only the external SSD and the charger, the external SSD light doesn't blink.
Tomorrow I will try to initialize the device by pressing PM_ONOFF.
If I hold down power for 5 seconds it turns on, but it's not SMC bypass mode, because it doesn't stay on with the fan running.
Testing the board with only the external SSD and the charger, the external SSD light doesn't blink.
Tomorrow I will try to initialize the device by pressing PM_ONOFF.
Pressing power button 5s turns on the board, but doesn't boot?
Do not confuse on board with working board.
Do you get CPU voltages at least?
Do not confuse on board with working board.
Do you get CPU voltages at least?
iClub
Member
Man, this Mac is very intermittent. I made a video of its behavior. Most of the time it doesn't turn on even when pressing power. At the end of the video, the device accelerates the fan.
L7430 0V
L7420 0V
L7410 0V
L7210 0.65V
L7220 0.75V
L7270 0.8V
drive.google.com
L7430 0V
L7420 0V
L7410 0V
L7210 0.65V
L7220 0.75V
L7270 0.8V
WhatsApp Video 2021-02-19 at 21.16.17.mp4
drive.google.com
Last edited:
Try again DFU mode.
If no important data, choose restore option; it will erase SSD!
If no important data, choose restore option; it will erase SSD!