Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
Yesterday, 03:57 PM
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Replies: 18
Views: 2,450
Re: Apple MacBook Air 820-00165 no PPVCC S0 CPU
Ok - you have at least a broken trace to this load switch.
This part (U8030) is acting like a solid state relay. When the C2 pin (EN) is logic high (~3 volts), this switch will pass the INPUT...
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
Yesterday, 03:43 PM
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Replies: 18
Views: 2,450
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
Yesterday, 03:28 PM
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Replies: 18
Views: 2,450
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
Yesterday, 03:12 PM
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Replies: 18
Views: 2,450
Re: Apple MacBook Air 820-00165 no PPVCC S0 CPU
Good ENABLE voltage for U7501 yet the output is still not valid.
Confirm the voltage @ L7560, pin # 2 (PP3V3_S5_REG_R).
If this voltage is not ~3v3, check for a short on this rail as follows:
...
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
Yesterday, 02:57 PM
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Replies: 18
Views: 2,450
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
Yesterday, 02:29 PM
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Replies: 18
Views: 2,450
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
Yesterday, 12:04 PM
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Replies: 21
Views: 295
Re: Asus UX330UA won't power on
No. The comment is only to offer closure to the missing part that is for the fuse. In this design, the USB connector is protected on the VBUS pin (supplies power to anything connected) through:
a)...
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
Yesterday, 11:08 AM
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Replies: 21
Views: 295
Re: Asus UX330UA won't power on
Ok - so it is a no care. The IC right above it is the current limit USB load switch.
That is, EITHER the fuse OR the IC @ U5206 is stuffed but NOT BOTH. We do a similar PCB layout in our product...
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
Yesterday, 11:06 AM
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Replies: 2
Views: 51
Re: Hp 840 g1 6050a2560201-mb-a03
Start with sheet 5 of the schematic = charger IC @ U6000.
Review the DCIN mosfets @ Q6010 & Q6011. Often the 2nd mosfet gets damaged.
Confirm the voltages on each of these mosfets (source ;...
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
Yesterday, 11:00 AM
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Replies: 21
Views: 295
Re: Asus UX330UA won't power on
The referenced area is linked to the power rails of the CPU. As these are very low voltage rails and sensitive to the logic board, we will avoid this area for now.
For the earlier question - the...
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
Yesterday, 09:07 AM
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Replies: 2
Views: 40
Re: Lenovo ThinkPad L13 18834-1M strange fault
See attached.
Remove all power. No adapter and no battery.
Meter in resistance mode.
Check and post the resistance of the following:
Source (1-2-3) and drain (5-6-7-8)
Source and gate (4)
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
Yesterday, 06:36 AM
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Replies: 21
Views: 295
Re: Asus UX330UA won't power on
Correct.
Most of the power regulators are buck style (they accept a higher input voltage and supply a lower output voltage). So your logic board starts with ~19v and drills down the voltage at...
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
Yesterday, 06:31 AM
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Replies: 22
Views: 472
Re: LA-C501P No ACDRV??
From the voltage on pin # 20 (VCC), the charger IC @ PUB01 is not being powered.
See attached.
Review the parts that have been highlighted.
The dual diode and series resistor must be present...
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
Yesterday, 05:24 AM
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Replies: 22
Views: 761
Re: Asus FX504 not charging battery
The battery is defective as this pin should not be 0 ohms when connected to the logic board.
This P_CLK pin is a signal that is used for communication with the logic board to share the battery...
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
Yesterday, 01:20 AM
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Replies: 11
Views: 1,353
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
08-07-2022, 07:44 PM
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Replies: 21
Views: 295
Re: Asus UX330UA won't power on
My bad...missed the post with the resistance readings. The coil resistance readings are low but they look to be ok for the low voltage rails which are likely for the CPU (~1 volt rails).
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Forum: Troubleshooting Laptops, Tablets, and Mobile Devices
08-07-2022, 07:17 PM
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Replies: 21
Views: 295
Re: Asus UX330UA won't power on
No, very likely not shorts but rather low resistance values for each. This is common to cpu core voltage rails. Low voltage rails will have low resistance values. Your referenced coils are close to...
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