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PPBUS_G3H - 8.56V
PPVRTC_G3H - 3.3V
PP5V_S5 - 5V
PP3V3_S5 - 3.3V
PP3V3_S3 - 3.3V
PP3V3_SUS - 3.3V
PP5V_S4RS3 - pulsing, vcore pulsing as well, no short to ground. I checked all the SPI traces and resistors, re-programmed bios with clean ME.
Any idea what to do next?
No water damage just...
The board stays on in normal mode, minus the vcore of course.
r7402, 7mv on pin 1 and 12.60v on pin 2. Even in SMC bypass, it measures the same
Also, resistance is 55k, which should be 90.9k, so I removed the resistor out of the circuit and it measures 90k to be sure it's good.
3V3_S5/SUS without bypass is 3.3v and SMC bypass is 3.3v as well.
AVREF_SMC is 3.3v with and without SMC bypass
I get voltage on all coils except the PPVCORE_S0_CPU_PH2 or PH1 and PPVCORE_S0_AXG_R in normal and in SMC bypass
Also noticed ppbus_g3h is 12.6v normal but in bypass it's 12.33v, I...
No pulsing all, when charger connected or triggering SMC_ONOFF_L, SMC Bypass, the fan does come on but no boot or chime.
Is it something with the bios/traces or clock signal?
Hello,
This board was liquid damaged, repaired and working. Somehow a screw dropped on it sometime after, no idea how they pulled that off. Anyhow, I was missing PP5V_SUS and Q7840 was replaced, PP5V_SUS came back.
Sometimes the fan tries to move bit stops, it's not even a quarter spin, it's...
Hello,
This board was liquid damaged, caps: c5025, c7526,c7525 was covered in liquid stuff. Also, U7200 was covered as well.
Replaced the caps and cleaned up the area and had to replace u7200 as it was blown.
Board boots and works fine all expect the camera and for some reason when I try to...
Before swapping out cap:
Do you note VCORE dropping 0.2-0.3V few seconds after start?
- yes, 1v then drops to .8v
Is better to confirm USB activity with OSX pen drive, with LED Link; if flashes OK.
- I have a USB stick with a LED on it that contains High Serria install, no flashing from it...
Hello,
I have an 820-2850 with no image and also doesn't chime.
Using 85w MagSafe official apple charger
If I take the memory out, it will beep and if I connect a mouse, it does light up.
I have tried another display as well to rule out a bad LCD.
No liquid, the board just stopped...
UPDATE on this and how it was SOLVED.
Short version, swapped SMC, firmware now updates and running on the newest OS with no issues.
Long version:
I found a way to manually push firmware updates to the BIOS.
You can get the firmware from unpackaging (Program such as unpkg) the install...