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#1 |
Senior Member
Join Date: Jun 2015
City & State: central java
My Country: Indonesia
I'm a: Knowledge Seeker
Posts: 132
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![]() please help where the problem is or if anyone has experienced please share. On the thinkpad W540, the voltage on the VINT20 drops gradually & slowly. If R380 is removed, at point DOCK_PWR20 appears voltage 20V. inject voltage on VINT20, nothing short. has been replaced mosfet Q9 and Q36, replace the processor, flash bios. but no change.
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#2 |
Senior Member
Join Date: Jun 2015
City & State: central java
My Country: Indonesia
I'm a: Knowledge Seeker
Posts: 132
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![]() any suggestion?
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#3 |
Badcaps Veteran
Join Date: Dec 2019
City & State: Windsor, Ontario
My Country: Canada
Line Voltage: 110VAC
I'm a: Knowledge Seeker
Posts: 4,077
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![]() Hi.
1) Remove all power -> meter in resistance mode (lowest scale) -> check the resistance to ground of VINT20. What is the reading ? Also post the meter scale. If the meter reports '1' or 'OL' (over limit) -> switch to a higher meter scale. 2) Check the first 2 mosfets for defects using the usual mosfet resistance checks. With NO power. Meter in resistance mode. check the resistance of each mosfet: source (1-2-3) & drain (5-6-7-8) source (1-2-3) & gate (4) gate (4) & drain (5-6-7-8) post the readings of Q9, Q36 mosfets along with the meter scale. 3) With the power on -> meter in 20v scale -> check the voltage reading of the following pins: ACDC_IN_CONN ACDC_IN F2, Pin # 1 F2, Pin # 2 U7, ACDET pin # 4 U7, pin # 36 (AVCC) U7, pin #15 (REGN) 4) Are you using a docking station ? 5) Are you using the official and original power adapter ? The ID pin on the adapter is being used to identify the presence of the original adapter so it must be used. |
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#4 |
Senior Member
Join Date: Jun 2015
City & State: central java
My Country: Indonesia
I'm a: Knowledge Seeker
Posts: 132
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![]() now the 20V voltage can enter across R340 by removing Q79 and adding R504. on the power button there is also a voltage of 3.3V. But still can't be switched on. after analysis, the -PWRSHUTDOWN signal only appears shortly after the PSU is connected, after that it disappears. does that indicate if the ThinkEngine chip is faulty? Has anyone experienced it?
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