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No boot 820-3476

R

raainxx

Member
Hi,
the customer say before intermittent start, but now no boot, green led and pass to orange without battery.
i check this voltage
PPDCIN_G3H = 16,84V
PPVIN_G3H_P3V42G3H = 16,33V
PPBUS_G3H_R = 12,57V
PPVIN_G3H_P3V42G3H = 3,427V
SMC_BC_ACOK = 3,387V
SMC_ONOFF_L = 3,415V
SMC_PM_G2_EN =3,414V
PP3V3_S5 = 3,335V
no liquid, the board is clean, what can i do?
thanks
 
D

dukefawks

Administrator
No fan spin or any S3 rails? Check for pulses on S3 rails, inspect closer for liquid damage. PPVRTC present?
 
R

raainxx

Member
No fan spin but not turn in start on this model (or just 2015?)
Sorry but what do you think about S3 rails? and check pulses on S3 rails, i don't understand where, i don't find on the schematic.
can you explain me for the S3 rails please?
I inspect all the board, i don't see liquid, the board is very clean.
PPVRTC_G3H = 3,3332V
 
D

dukefawks

Administrator
S3 as in the power state like S0, S3, S5. On the newer boards like this they mostly call it S4 now. So check for power pulses on 5V_S4 rail. If the board is power cycling there will be very short pulses which are hard to catch on a multimeter. If you have an auto range meter it will never see them. Preferably use a scope to catch the pulses.

Few more things you can check is SMC_ ADAPTER_EN, DSW_PWRGD. Check all rails for short to GND. Inspect the usual suspects for corrosion: U1900, U1950, U6100 and the termination resistors in the data lines to U6100.
 
R

raainxx

Member
I don't see anything on PP5V_S4, just 5V no short pulse with my scope. it's another signal?
SMC_ADAPTER_EN = 3,34V
PM_DSW_PWRGD= 3,34V
i check all rail no short, good voltage, no corrosion, very clean board. The CPU is warm, is it the CPU?
 
D

dukefawks

Administrator
CPU cannot be warm is it does not power on. The only way the CPU can get warm is a shorted FET. Some voltage must get to the CPU somehow. PPVRTC present? U1900 getting warm too?
 
R

raainxx

Member
No it's really the U0500 who warm at 70°c when i plug the power cable. I check with thermal camera, when i remove the cable the cpu temperature fall.
what do you talk about FET? example please?
PPVRTC_G3H = 3,3332V
No U1900 is not warm, only warm because CPU is on the other side.
thanks
 
R

raainxx

Member
Sorry but i try to understand, why is it a waste of time? do you think if i change the CPU, the board don't work? or it's more difficult than the GPU? or anything else?
thanks
 
D

dukefawks

Administrator
Go and see how much a CPU would cost first......
Then there is the ME region BIOS issue. Also need to fix what killed the CPU. Then you have to pray it works and there is not more damage. As I said, a waste of time.
 
ALB-Repairs

ALB-Repairs

Member
dukefawks said:
Go and see how much a CPU would cost first......
Then there is the ME region BIOS issue. Also need to fix what killed the CPU. Then you have to pray it works and there is not more damage. As I said, a waste of time.
Click to expand...

Hell, try reflow/ reball one and watch the CPU warp super bad, Havent figured a way round that yet myself.
 
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