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本帖最后由 vusalcrm 于 2020-5-4 00:56 编辑
Model: HP Pavilion DV7
MotherboardCode: Quanta UT3 DIS Only
Hello to everyone 
A laptop came to my service. Motherboard does not start. I connectedit to the power supply.
I connectedit to the power supply . Standby mode 0.004A . I started measuring.
1. Measuring VIN +19V –OK. Both mosfetswere open. +19 voltages were shared on the motherboard
2. Then I measured the values of the standbypwm coils (PL8 and PL9) PL8 > +5VPCU = 2.3K and PL9 > +3VPCU =3.1K (an average value) no short circuit.
3. I reconnected the power supply and imeasured the supply voltages. PL8 > 0.507mV PL9 > 27.3mV ( this is not normal )
4. Standby voltage controls on the motherboard PU2 (RT8206B) Need to die the main voltage coming to the chip first. Measuring RT8206B 6PIN. Low voltage passes across the resistor to the other side. PR22 1R resistor SMD Code 1R0 . Measured the resistance (PR22 – 137K) this is not normal.
I measured the LDO voltage (RT8206B PIN7). There is also strangeness here. (Normal voltage LDO +5.0V)
Replace resistance add 2R2 (2.2R). +19 voltage fully input.
Connected the power supply. there is also strangeness here. standby mode 0.049A . There is a short circuit
I examined with thermal camera and the heated PWM RT8206B. Changed PWM.
Connected the power supply everything is normal standby mode 0.007A . Voltage normal at standby coils
And the expected moment has come  Happy Ending...
Note: The problem with this motherboard is due to low quality adapters. such products often damage laptops. I met often
Good day... 
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