djdblaster
New member
Okay, this board was nasty around U3890 so I put it in through UC (first bath UC, finally). PPBUS was shorted so I removed Q3880 and short was gone. Other stuff should also be replaced, but that can wait I think.
Always present rails are good. PP3V42 and PPBUS are 3.42V and 12.59V.
Then I proceeded to check other rails, PP5V_S5 and PP3V3_S5 are also good. That's about it for the rails. PP5V_SUS and PP3V3_SUS are not present. They share Q7822, which fails because P5V_3V3_SUS_EN is not present. It is created by U7940. U7940 VCC Pin and SMC_BATLOW_L are present. PM_SLP_SUS_L is not present. It comes from PCH. Checked input signals and found only SMC_ADAPTER_EN present. PM_RSMRST_L is not present.
Traced that back and got to U7930.
Pin 1 RESET ----- 0V
Pin 2 GND ------- 0V
Pin 3 NC --------- 3.3V?
Pin 4 CT --------- 0.08V
Pin 5 SENSE --- 0V
Pin 6 VDD ------- 3.3V
Probably should have just written rail names. Okay, so, I've replaced it with another one, same results.
Q5040:
SMC_BATLOW_L is 3.3V
PM_BATLOW_L is 0V
PP3V3_SUS is 0V
Reading datasheet about it says that Pin 1 Reset RESET remains low (asserted) for the reset period after both SENSE is above VIT and MR is set to a logic high. A pull-up resistor from 10 k? to 1 M? should be used on this pin, and allows the reset pin to attain voltages higher than VDD.
Tell me please I am in a wrong rabbit hole.
I?m using 2 original 60W and 85W chargers.
Always present rails are good. PP3V42 and PPBUS are 3.42V and 12.59V.
Then I proceeded to check other rails, PP5V_S5 and PP3V3_S5 are also good. That's about it for the rails. PP5V_SUS and PP3V3_SUS are not present. They share Q7822, which fails because P5V_3V3_SUS_EN is not present. It is created by U7940. U7940 VCC Pin and SMC_BATLOW_L are present. PM_SLP_SUS_L is not present. It comes from PCH. Checked input signals and found only SMC_ADAPTER_EN present. PM_RSMRST_L is not present.
Traced that back and got to U7930.
Pin 1 RESET ----- 0V
Pin 2 GND ------- 0V
Pin 3 NC --------- 3.3V?
Pin 4 CT --------- 0.08V
Pin 5 SENSE --- 0V
Pin 6 VDD ------- 3.3V
Probably should have just written rail names. Okay, so, I've replaced it with another one, same results.
Q5040:
SMC_BATLOW_L is 3.3V
PM_BATLOW_L is 0V
PP3V3_SUS is 0V
Reading datasheet about it says that Pin 1 Reset RESET remains low (asserted) for the reset period after both SENSE is above VIT and MR is set to a logic high. A pull-up resistor from 10 k? to 1 M? should be used on this pin, and allows the reset pin to attain voltages higher than VDD.
Tell me please I am in a wrong rabbit hole.
I?m using 2 original 60W and 85W chargers.
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