jowell
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Basic Fault Findings for No Power Laptop
(Applicable for other units with the same reading below)
Note:
Always test your charger first and make sure it has a 19v output. Plug it in, if you observe that the charger led has shut off it means that the voltage protection of the charger detect a problem from your laptop. Common issue is a shorted components (Short to Ground).
How to test it where should we start?
We should start from the sense resistor (Shunt resistor) this is connected from the Dc Power Jack and the 19v power rail of the laptop
Select Resistance Test from Your Digital Multi Meter
· The normal reading must be Mega Ohms (Note: if the reading is K Ohms there is a leak from a high side mosfet.)
· But take note that for this issue we should expect a low resistance reading.
Easy and Shortcut method for this is using Voltage injection technique
· For safe voltage injection select 1-5V Range and 2.5A Max
· By injecting this amount of voltage and range of 2A we expect that the Bad component will get hot.
· We can use Thermal camera or feel it by touching the suspected components. This is the connected components from 19v power rail.
· Now if you determined the faulty component is a capacitor replace it with the same size or value. Test it again using resistance test
The normal reading must be mega ohms and if the reading is normal it means the repair Success.
(Applicable for other units with the same reading below)
Note:
Always test your charger first and make sure it has a 19v output. Plug it in, if you observe that the charger led has shut off it means that the voltage protection of the charger detect a problem from your laptop. Common issue is a shorted components (Short to Ground).
How to test it where should we start?
We should start from the sense resistor (Shunt resistor) this is connected from the Dc Power Jack and the 19v power rail of the laptop
Select Resistance Test from Your Digital Multi Meter
· The normal reading must be Mega Ohms (Note: if the reading is K Ohms there is a leak from a high side mosfet.)
· But take note that for this issue we should expect a low resistance reading.
Easy and Shortcut method for this is using Voltage injection technique
· For safe voltage injection select 1-5V Range and 2.5A Max
· By injecting this amount of voltage and range of 2A we expect that the Bad component will get hot.
· We can use Thermal camera or feel it by touching the suspected components. This is the connected components from 19v power rail.
· Now if you determined the faulty component is a capacitor replace it with the same size or value. Test it again using resistance test
The normal reading must be mega ohms and if the reading is normal it means the repair Success.
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