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820-00239 20V 0A

A

ajdoc

Member
No liquid damaged.
Found fried U8209, U7650 (P5VS4_SW had short and pad was fried), U8400 and there was short to ground on F7000/2.
Then found U7600 was getting hot.

All of that has been replaced.
Short on PPBUS is gone and there was 5V from charger and then it switch 20V for split second U2800 had hot spot and in loop to 5V again.

U2800 replaced and got stable 20V 0A

PPBUS 13.01V
PP3V3_G3H 3.4V
PP3V3_G3H_SMC_ISNS 3.39V
PP3V0_G3H 2.99V

PP1V8_SUS pulsing from 0v to 1.5V
PP1V0_SUS pulsing as well
PP5V_S5 4.95V but every couple of secunds "Shock Hazard" light is flashing on Fluke 17B+
PP5V_S4 0V
PP3V3_S5 plusing 3.35V


Any idea?
 
A

ajdoc

Member
5V_S0 0.064 in diode mode
Injected voltage and Q8209 gets warm.
Replaced Q8209 one more time and now have 0.321 in diode mode on 5V_S0.

5V_S4 0.02 in diode mode
Injected voltage and U7800 gets warm
Replaced U7800 but still the same readings and it gets warm.
 
2informaticos

2informaticos

Administrator
Staff member
"Replaced U7800 but still the same readings"
Didn't want to know the reading with U7800 removed???

You must find the culprit from 5V_S4 power rail.
 
A

ajdoc

Member
Found short on PPV5_USBC_T_PVVC.
Replaced UB700 and now have 5.12V on PP5V_S4

No more loop from charger.
Without battery stable 20V 0.09A

PP5V0 5.11V
PP3V_S0 3.35V
PP1V8_S0 1.78V

Wont go into DFU.

When battery connected it take around 2A from charger.


Any idea?
 
2informaticos

2informaticos

Administrator
Staff member
The board goes into S0 state, so power on sequence isn't broken.
What for DFU, if is T1 machine (not T2)?

What is CPU core voltage behavior?
 
A

ajdoc

Member
Yes, there is no T2, forgot about how old is that board.

PPVCC_S0_CPU and big coils have stable 0V, no spikes etc when charger connected
 
A

ajdoc

Member
L7900 1.2V
L7960 0.97V
L8050 1V
L8000 1V
L7270 0V
L7220 0V
L7210 0V
L7410 0V
L7420 0V
L7430 0V
L7700 1.05V

Is there any chance U7410/20 etc are faulty even if they are not shorted to ground?
Or U7100 is faulty?
 
2informaticos

2informaticos

Administrator
Staff member
Do not expect voltage on iGPU yet (L7410-30).
L7270 should get voltage before CPU core (L7210/20).
Try known good BIOS.
 
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