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[SOLVED]power on problem with 820-3330

D

Dozer

Member
i just working on that board.

it had a bit liquid near smc and u1800

no green light no fan spin

i found PPBUS_G3H on F7040 is 12.22V so smc not working

i found 3 bad resistors R5000, R5076, R5087 after replacing I get 12.54V and a green light, so that is ok, fan is spinning

no sound no video no Voltage on L7550 and 7560

i found that duke wrote in the forum there is only power after initalizing the gpu. if i understand right it means problem with initalising gpu.

L8930/60 has 0.91V (both pin2)

is it possible that the bios is not working? on wich point the bios is loaded?
 
D

Dozer

Member
forgot, Y8700 has a nice waveform 27Mhz on Pin 1 and Pin 3

i just swaped the u6100 from a good board but not better, PP3V3_SUS is 3.3V

I checked the caps above the gpu both ends all reading in diode mode about 0.340
 
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D

Dozer

Member
i just reballed the smc, looked not nasty under it.

now i have still no Voltage on L7550 and 7560

but L7510/20/30 was before reballing about 1.0 - 1.12V, now is about 0.92,
 
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D

Dozer

Member
i connected the board to an lcd and... it works.

so duke, no Voltage on L7550 and 7560 before initialising the lcd?

so i think the solution was to reball the smc like duke suggested. after that changed the voltage on L7510/20/30
 
D

Dozer

Member
i tested the board now in the machine and still found a coroded j6955 after replacing, that was not easy, the board say no audio device found

before replacing J6955 audio and mic was working good.

what could here happend? need still help please.
 
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