Macbook Air 820-3209-A No chime No image

[Ciki]

Macbook start but no chime and no image PPBUS_G3H ,PP3v42_G3H, ok ,on R7402 Ton Pin 1 only 0.334V and pin 2 is 8.4V ,try to replace u7400 same ,ton pin measure ok 90K

 

[aprendiz]

Voltage on CPU Vcore??
History?
Any activity on USB?

 

[Ciki]

Voltage on CPU Vcore is 0.8100V ,no obvious damage ,looks clean ,no activity on usb

 

[JohnB8812]

.81 would mean VCore is present. PRAM reset done? How does BIOS and clock chip areas look?

 

[Ciki]

Bios looks ok ,clock signal is 3.4V

 

[dukefawks]

Only thing to try is another BIOS. After that it is probably bad RAM as is so common on these boards.