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#1 |
New Member
Join Date: Feb 2022
City & State: DE
My Country: DE
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Posts: 10
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![]() Hello,
Need help. I‘m working with dead Lenovo V-15 ADA (motherboard GV451&GV551 NM-D151). The laptop is quite new, mfg date 2020-10. Can‘t find any schematics for it. One of the chip LV5028 had a burned spot on it. Before ordering it from China, decided to do some measurements with chip removed. And now I‘m not sure will the new chip solve the problem. There are suspicious readings (chip desoldered): Pin 5 – 0.4Ohm Pins 7+8 – 5Ohm Pins 17+18 – 0.5Ohm Pins 12+13+14+15 - 4.6Ohm Found some datasheet of this chip (attached). Are theese readings normal? Or the problem is not only the chip? |
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#2 |
New Member
Join Date: Feb 2022
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![]() Any thoughts?
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#3 |
Badcaps Veteran
Join Date: Jun 2015
City & State: siliguri
My Country: india
Line Voltage: 220vac,60hz
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![]() Remove PL500 & PL502 and re-measure the resistance on pins you mentioned. If resistance improves significantly, the ic is likely ok and problem is on the load side.
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#4 |
New Member
Join Date: Feb 2022
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![]() Nothing changes with 500 and 502 removed. These lines are feeding the CPU, right? Maybe then such a low resistance is normal?
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#5 |
New Member
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#6 |
Badcaps Veteran
Join Date: Dec 2019
City & State: Windsor, Ontario
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![]() Post the measured resistance values from your testing.
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#7 |
New Member
Join Date: Feb 2022
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![]() All values are at the first post. Measured with chip removed:
Pin 5 – 0.4Ohm Pins 7+8 – 5Ohm Pins 17+18 – 0.5Ohm Pins 12+13+14+15 - 4.6Ohm Removing jumpers doesn't change anything all values remain the same to the load side. |
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#8 |
Badcaps Veteran
Join Date: Feb 2020
City & State: Noosaville
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![]() When I see a simultaneous short on +1V and +3V rails, the PCH section of the CPU is usually the cause. Confirm with 1V voltage injection and thermal camera. Board will be good as a donor only.
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#9 |
Badcaps Veteran
Join Date: Jun 2015
City & State: siliguri
My Country: india
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![]() @reformatt is 100% right in assuming that.
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#10 |
New Member
Join Date: Feb 2022
City & State: DE
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![]() Injected 1V, it draws 1.8Amps and one corner of the CPU gets slightly warm (only visible with thermal cam, can't feel with the finger). So, it's dead CPU
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