Laptop Model: HP PROBOOK 4320s
Board Number: Quanta DASX6AMB8G0
Fault : Simply Dead
Motherboard Picture:
Repair process:
Fault current: 0.002. When
I press the switch, there is no current. I find that the EC standby power
supply is low, only 1.35V. I trace the source.
After EC standby comes out normal, the standby current returns to
0.007, and is triggered to 0.057 by pressing the switch.
It was found that there was no standby, and after tracing, it was
found that the cause was no voltage at the common point.
( The oscilloscope only operates at 5V when the G
pole of the upper and lower tubes is turned on)
Point cuts generate common
point conditions;
The actual measurement found that there is no ADP_EN, it is always
low level. After replacing the EC, the sound is still the same.
Follow its conditions to
discover the enemy's situation.
A common
problem encountered is that PD35 causes abnormality in the middle pin of the
adapter. This case is a disconnection. After flying the lead, the
common point voltage is OK.
Press the switch and the current will jump to light up the Laptop, and the maintenance is completed.
Happy Repairing!!
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