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本帖最后由 vusalcrm 于 2020-6-24 05:32 编辑
Model: Toshiba Satellite C660
Motherboard Code: LA-6842P Rev 1.0
Hello to everyone Motherboard does not start. Current draw with adapter connect (0.045A -0.056A) Battery is connected. Only start led light active (low). But no start
I connectedit to the power supply and watched it with a thermal camera. Heated part MOSFET (at the second MOS) P Channel 30V
Let's start measuring with a multimeter. Both MOSFET are intact ( M1 and M2 p channel)
No short circuit in +19V line 7.26mOhm (Normal)
Need to measure standby voltage coils +3VALWP Coil – 8.57kOhm (Normal)
Need to measure standby voltage coils.
+5VALWP Coil – 14.10kOhm (Normal)
Then let's measure the value of the LDO line.
LDO +3.3V – 45.2Ohm (short circuit)
Then let's measure the value of the LDO line.
LDO +5.0V – 36.52kOhm (normal)
Let's separate the standby PWM on the motherboard (TPS51125A) Then let's measure the value of the LDO line.
LDO +3.3V – 45.2Ohm (short circuit) There is still a short circuit in the LDO+3.3V line
Let's give 3V to the short circuit linefrom outside
Thermal camera comes to help  Heated part SIO ENE KB926QF
Let's take it off the motherboard SIO. And let's remeasure the LDO +3.3V line. No short circuit.
LDO+3.3 – 1.34mOhm (normal) Very Good.
I can't solder the standby PWM and replace new SIO KB926QF
Let's connect the motherboard to the power supply
Measure the standby voltage. Very good. The voltages are OK
Happy ending... Good day 
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狗仔卡
发表于 2020-6-24 05:22:52
支持！
反对！
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