| Electronics > Beginners |
| Repairing short circuit in laptop |
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| mdijkens:
Hi, I am trying to repair the ASUS ROG G751JY of my son which has a short in the power circuit. Without having much knowledge, experience or information I am finding my way throught the power circuit part. Near the 2 mosfets there's a small SMD component which I assume is a tantalum (??) or maybe a diode (?) but can't find any info on. See attachment. I desoldered it and it measures a dead short both ways and no capacitance. Does anyone know what component this is? For problem finding I am thinking of putting my lab power on it with current limiting on 1A (for a brief moment) and spray alcohol over the components to see which ones get hot. Is this a good approach? |
| wraper:
Looks like Panasonic poscap (tantalum polymer). Seem to be 15uF, not sure about series and voltage rating though. EDIT: but it seem to be rather big, so I'd guess it could be 35V. Is it connected in parallel to charger input? |
| mdijkens:
Yep that looks like it. Probably 25V or higher (for a 19.5V power supply) If I measure it (off board), it's a dead short and no capacitance. Since I don't have a spare, Just trying to power the board without it, but that doesn't work: No short but also no power consumption 0.000A Could that be a critical piece? I would at least expect the laptop to consume something if this cap was the only problem ... |
| ArthurDent:
The capacitor shorting could have taken out other parts as well. The 2 parts marked 4983NZ are MOSFETs which could have been used as switches. Here's the data sheet. https://www.onsemi.com/pub/Collateral/NTMFS4983NF-D.PDF |
| wraper:
Probably blown fuse as well. Also measure resistance of R005 part on top right corner which seem to be 5 mOhm shunt resistor. |
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