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Have this MacBook air 2018 version with T2 chip that was sent in due to not being able to load OS. It powers on to question mark folder. When i attempt the recovery process, the progress bar for the internet download starts to jump about. Also, the fan is running very high after about a minuter...
Hello Jents,
Have another board here that's not powering up. Had some corrosion/liquid damage on and around the backlight caps C8473 - 8469 and 8461 and 64.
PM_PCH_PWROK - 3.3
PM_PCH_SYS_PWROK - 0.0
ALL_SYS_PWRGD - 3.22
CPU_VCCST_PWRGD - 0.997
SMC_PM_G2_EN - 3.4
PP3V3_S0 - 3.3
PP5V_S0 - 5.1...
With USB keyboard it worked. It appears i've got corroded via's. This may very well be the same issue that's causing my video issue, corrosion. Looking deeper into the board, it appears the previous owner or shop had performed corrosion cleaning of the board. I'm thinking i'm done with this board.
There appears to be other issues with the board that may be linked. I can't perform PRAM reset, as in the board is not responding to the key commands. I am however able to perform the SMC reset.
Connected an external hdd and the drive had activity, granted no real way to tell if it was transmitting data, just the sound of the drive motors and the led flashing to signify comm activity.
I've used the hardware mode and basically disables the AMD GPU. But each time I did use the mode, I was always able to initially boot into safe mode before the mode was applied. This time around, i can't even get into safe mode.
No, the caps lock isn't responding.
I'm however able to insert...
USB activity: Basically pulsing LED.
The frame boots up with keyboard backlight coming on around the time the OS should be fully loaded.
So if it is the GPU, that would mean the main GPU is what is bad, correct, and so bypassing the second GPU (higher graphic GPU) won't solve this issue?
Have this board (820-3330) that came in with no image or backlight on the display. LCD_BKLT_EN and LCD_PWR_EN both reading 0volts.
i've confirmed its not the display. I also replaced the lvds connector.
PPBUS_S0_LCDBKLT_FUSED - 12.4
Any suggestions?
So started looking BKL_EN and found something interesting.
LCD_BKLT_EN - 3.3
LCDBKLT_EN_L - 0
LCDBKLT_EN_DIV - 11.9
PPBUS_SW_LCDBKLT_PWR - 3.2 at max lcd brightness
PPBUS_SW_LCDBKLT_PWR - 10.8 at 5 bars lcd brightness level
BKL_EN - 0.05 at max lcd brightness
BKL_EN - 2.68 at 5 bars lcd...
I've replaced the LCD connector twice
I can get the backlight to work up to about the 5th bar in the backlight intensity level, above that is when it starts to flicker.
Backlight voltage is about 29v when the brightness intensity is at the 5th bar, once i increase the brightness into the 6th...
PP5V_S0 - tries to come on. Goes up to 0.7 then drops (same as with the fan coming on and off)
All the coils are doing the same thing as PP5V_s0 as the pulse up and down, except the lcd backlight which expected since the display is not connected.
ALL_SYS_PWRGD - goes up to 1.6 before dropping...