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820-2915 missing CPU VCORE

bighead

bighead

New member
Hello!

This board was clean or cleaned before I received it. Can't see any corrosion.

It does not charge the battery and it won't turn on from just power adapter.
If I install battery it goes to S0 state, but no CPU VCORE.
Fan is not running. GPU gets hot.

Missing ALL_SYS_PWRGD so no CPUIMVP_VR_ON.

I checked Q7950 and I have everything for ALL_SYS_PWRGD, but it stays at 0V.

I checked:

R7968
R7966
R7965
R7964
R7963

and are all 0V. However I'm sure I have PP1V5_S0 , PP5V_S3 etc.
However P1V5S0_PGOOD, P5VS3_PGOOD etc. signals are 0V.

I believe ISL fucked, but it looks clean. I checked sense resistors and traces and all looks ok.
I have green light, but with power adapter I don't have PPBUS_G3H. It's like 1.8V. With battery is all ok.
No short on PPBUS_G3H.

Should I first fix the PPBUS_G3H issue?

Thanks.
 
D

dukefawks

Administrator
No use fixing PPBUS_G3H, it should run from battery. All PGOOD signals are tied together, so if one is pulling it down all will be low. Look at the diagram and measure all voltages that are required to generate ALL SYS PWRGD. 4 voltages on Q7950 and 3 on U7960 and all the PGOOD signals from regulators.
Seeing as you are missing PPBUS_G3H and at least one PGOOD signal I would say this was a liquid damaged machine.
 
bighead

bighead

New member
I checked the voltages on Q7950.
These are measured ok:

PP3V3_S5
PP3V3_S0
PP1V5_S3RS0_CPUDDR
PP1V05_S0

On pin 4 I have nothing. 0V

U7960 is not on the board. Only different voltage is PP5V_S0 which is present.

PP1V5_S0 is present
PP1V8_S0 is present
PP5V_S3 is present
PP1V05_S0 is present
PPVCCSA_S0 is not present

Looks like I have to find out why I don't have anything on L7100.
No short. I checked U7100 and looks ok. I measured 3.3V on EN pin and I also have 5V on VCC and PVCC pins.
 
D

dukefawks

Administrator
Dead U7100 does happen. But I also have a 2915 here with this issue and I can't get it fixed. When flexing the board sometimes I get VCCSA. Good luck with this one.
 
bighead

bighead

New member
3 Beeps in both of the slots. I'm going to check U7300.

Edit: Unfortunately I've 1.5V there.
 
Last edited:
bighead

bighead

New member
Yes, I'am. I also tried it with different modules. I checked the pins in the memory slots. Everything looks ok.
I checked the voltages at the memory slot and looks like I've everything there. Bad slot or CPU?
 
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