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Old 10-19-2021, 08:27 AM   #1
Fabbrone
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Default Dell precision 7520

Hello, the problem with this notebook is that it turns on only with the power supply but not with only the battery. The battery charges it but as soon as you disconnect the power supply it turns off.

MOD EDIT: precision 7520 not 7250. Thread title changed.

.

Last edited by SMDFlea; 10-26-2021 at 09:30 AM..
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Old 10-19-2021, 08:35 AM   #2
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Default Re: Dell precision 7250

Check BatFet and Share Schematics pls, If available
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Old 10-19-2021, 08:42 AM   #3
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Default Re: Dell precision 7250

Quote:
Originally Posted by Sephir0th View Post
Check BatFet and Share Schematics pls, If available
not available
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Old 10-19-2021, 08:58 AM   #4
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Default Re: Dell precision 7250

Then Share clear Pics of the DC-IN Circuit. At least Mosfets and the Charging Controller should be visible.
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Old 10-19-2021, 09:59 AM   #5
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Default Re: Dell precision 7250

Ok a pics dc-in and battery zone
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File Type: jpg 1634658886998.jpg (701.0 KB, 19 views)
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Old 10-19-2021, 11:13 AM   #6
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Default Re: Dell precision 7250

Do you know how to Check these mosfets?
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Old 10-20-2021, 09:16 AM   #7
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Default Re: Dell precision 7250

a mosfet is EMZB08P03V with a multimeter negative on Drain and positive on Source is open . On reverse a multimeter bip. Positive on gate and negative on Drain or Source is open. Reverse ther is a resistance
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Old 10-21-2021, 02:18 AM   #8
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Default Re: Dell precision 7250

This mosfet should Not beep or Show Low Ohms in any Case. If so, Remove it and Check the empty Pads again. If confirmed, replace it. The issue might be solved after.
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Old 10-21-2021, 04:25 AM   #9
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Default Re: Dell precision 7250

first check adaptor on bios is detected or not
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Old 10-21-2021, 08:49 AM   #10
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Default Re: Dell precision 7250

How did you confirm the battery is indeed charging? Have you tried with a known good battery and see if the problem is still there?

I suggest you try the software below first to confirm if your battery is charging. Post screenshots of your results. https://www.passmark.com/products/batmon/

Quote:
a mosfet is EMZB08P03V with a multimeter negative on Drain and positive on Source is open . On reverse a multimeter bip. Positive on gate and negative on Drain or Source is open. Reverse ther is a resistance
Do not rely on beep alone. Post the values you are measuring, which setting are you using (diode, continuity or resistance mode) to measure the values as well as probe location (where is black and red probe connected).
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Old 10-22-2021, 04:07 AM   #11
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Default Re: Dell precision 7250

The test I did with the soldered mosfets by putting the black probe on the Source there are 0.5Mohm even by inverting the pins. Black probe on the gate and red probe on source and drain 2.5Mohm inverting me from open circuit.
However, I believe that if these two mosfets were faulty the notebook would hardly turn on.
Excuse my language, I repeat the problem of the laptop if I connect it to the adapter it turns on and works correctly but does not charge the battery. If the battery I load it with another laptop ok and I put it on this faulty one it turns on and works until the battery runs out.
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Old 10-22-2021, 08:51 AM   #12
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Default Re: Dell precision 7250

Post schematic for your motherboard (also provide board reference). If you cannot find one, make a request in the schematic section.

1. Try with a known good original charger.
2. Check if middle pin is making proper contact with the DC jack.
3. Check if the wire at the DC jack is not broken.
4. Check if there is proper connection between DC jack and DC socket on motherboard.

With battery and charger connected (laptop off), measure voltage on all battery pins and report back (it would be helpful if you can take a picture of the battery connector on the board and label is with your readings)
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Old 10-26-2021, 09:26 AM   #13
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Default Re: Dell precision 7250

I have to correct the model which is actually a precision 7520 not 7250. I checked the voltages on the connector of the inserted battery and inserted adapter . On all pins there are 0 Volts except the 3 pin from the left there are 4.7V

A jack connector is ok

A board is CAPOO LA-E311P Rev 1.0
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Last edited by Fabbrone; 10-26-2021 at 09:29 AM..
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Old 11-03-2021, 10:04 AM   #14
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Default Re: Dell precision 7520

This is a diagram, thank Rezistor
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