Re: Dell Inspiron 6400 can't turn on
Search the entire board for components that become hot, not just the surrounding area of PQ42. The shorted component may be placed far from PQ42, but still connected to +PWR_SRC
SteveHart
Member
Last Activity: 02-09-2025, 11:54 PM
Joined: 03-21-2012
Location: Mataram
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Re: Dell Inspiron 6400 can't turn on
As usual, check the mosfet out of the board. If it is short, it is the culprit. If it is tested ok, then you'll have to search other components the same way as you did before, only this time with the second mosfet out of the circuit.
For the mosfet replacement, it's not always true odd number is P channel and even number is N channel mosfet. It depends on the manufacturers numbering system. And even when it's the same channel type you should consider things like voltages, ampere, Rds on characteristic of the mosfet. Better to read...Leave a comment:
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Re: hp mini 210 no display
In my experience with that model, reflashing the BIOS always do the trickLeave a comment:
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Re: Dell Inspiron 6400 can't turn on
Assuming the FET is now off board , feed the voltage after the FET. In the schematic it is marked as DC_IN+. Apply the voltage to the drain (pads) of PQ6. Read fddizon post earlier...Leave a comment:
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Re: Dell Inspiron 6400 can't turn on
Good point Fddizon, thanks for your input. Yes it would be safer to do that. Surely enough when injecting voltage to the other rails it should not exceed the voltage the rails designed to be. Have done a couple or more unnecessary damage by that stupidity myself.
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Re: Dell Inspiron 6400 can't turn on
Yes, you should manually adjust the current. The reason that I ask you to limit the current to 1A is to avoid the FET (PQ6) getting too hot and broken while you search for the shorted component.
As dj_ricoh said, if you take out the FET, you just simply take out the 19V rail. Hence there will be no current flows to the rest of the circuit. So if the FET is measured OK outside the circuit, you can put it back in the circuit, and do the power supply test once again. This time try to find other components that becomes...Leave a comment:
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Re: Dell Inspiron 6400 can't turn on
First thing you must do is to lower the current limit. Ussualy 1A is enough. After that you can search the component that is shorted by lightly touching the components directly connected to the 19v rails and find the one that becomes very hot. That component is the culprit. FETs, diodes, and caps are the most likelyLeave a comment:
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Re: Acer Aspire V5
It's F2. Unplug the battery firstLeave a comment:
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Re: Motherboard schematics archive?
I guess I have some schematics to share tooLeave a comment:
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Re: Motherboard schematics archive?
Can I have the username and password please?Leave a comment:
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Re: New Members - please post your introductions here
Hi, My name is Steve. I'm from Indonesia. Working as a laptop tech, mostly in software area. Know (very) a little about electronic, and hoping that i can learn a lot about laptop repairing.Leave a comment:
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