If PU301 is overheating, remove all power. Meter in resistance mode. Measure the resistance to ground of each output rail on this device....
mon2
Badcaps Legend
Last Activity: Today, 09:37 AM
Joined: 12-15-2019
Location: Windsor, Ontario
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If PU301 is overheating, remove all power. Meter in resistance mode. Measure the resistance to ground of each output rail on this device....Last edited by mon2; Today, 09:37 AM. -
Who is driving the mosfet? Can you identify the driving chip? Is it the charger IC? If yes, which is onboard and which pin is used to drive the mosfet?Leave a comment:
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Share a pic of the board with this part. We can use boardview and then the schematic to find this device.Leave a comment:
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Interesting...did not know this. Thanks.Leave a comment:
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Pour some alcohol on the top surface of UZ2. This will enhance the markings. Then take a clear pic of the top surface. What are the markings? The very large PCB traces hints that the same rail is being shared by a device that consumes heavy currents. Where does this area lead to?Leave a comment:
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Can you define unstable? How bad are the fluctuations?
Suggest to flux and remove the white fuse @ F5200. Then measure the voltage to ground again at F5200, pin #1. Is it stable? What is the voltage?
What is the voltage of 3V8_AON (measure @ C5895)?
reference:
https://boards.rossmanngroup.com/thr...0-02016.65022/Leave a comment:
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The signal line is active LOW (denoted by the tilde prefix) so if the voltage is ~0v (ie. as you are measuring @ 0v13) - the DRAM is parked in the RESET state....Leave a comment:
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Low voltage rails will be low in resistance by design. These measurements look ok to me. Not shorted.
What is the voltage to ground on pin#1 on the charger IC? pin #2 on the charger IC? Connect the adapter only to measure.
Then connect both, the adapter and battery. Test these 2 pins again for their voltages....Leave a comment:
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Yes. You can download it from the Texas Instruments website.Leave a comment:
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You cannot measure resistance if the power is on.
Does the laptop turn on with the power adapter? What does Windows show for the battery?Leave a comment:
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Which part is PUG8? Is it the 3H=8H regulator?
This is Richtek RT6585BGQW
https://www.richtek.com/assets/produ...85AB_DS-07.pdfLeave a comment:
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Now connect the adapter but do not power it. What is the resistance now? Then power up to test again.Leave a comment:
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S/G is too low. Flux and remove this mosfet. Allow the mosfet to cool. Test the S/G resistance on the mosfet. Is it still this low? A good mosfet should be hundreds of k ohms or higher. The current resistance indicates the mosfet is defective.Leave a comment:
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So the regulator is not shorted but downstream consumer side is. Measure the resistance from the solder blob to the pch 3v3 rail. The pch uses the same power rail. It is possible the cpu is dead from this event but to be determined.Leave a comment:
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From pins 17 & 18 on PU301 - the +3VALWP is shorted.
Locate a solder blob @ PJP302. This blob shorts +3VALWP to +3VALW. Remove this solder short and then measure the resistance to ground on PL301. No power to the board during this test. Is PL301 still 10R9 ohms to ground?Leave a comment:
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Well done!Leave a comment:
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What is the exact voltage to ground of PPBUS_AON @ white fuse F5200?Leave a comment:
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Test the resistance across the 2nd dcin mosfet.
source / drain
source / gate
gate / drain
often 2nd dcin mosfet is defective and takes down the 1st dcin mosfet since they share the gate pins.
no power to the board during these tests.Leave a comment:
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The current draw starts and peaks to this value then repeats? Same if using other usb ports? Flip the cable head by 180 degrees to test each side of the connector.Leave a comment:
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