Fujitsu Lifebook Power IC gets hot
Hi everyone,
I'm brand new to the forum. I've found this site because I have a very similar problem like this guy. It's also a Fujitsu Lifebook and has the same symptoms: LEDs briefly flash when connecting the power adapter, battery doesn't charge. Same behaviour when connection 14.4V to the battery pins.
I have 0 experience with motherboards but I do have an electronics background, I am an electronic engineer but I have to say there's some dust on that knowledge although I play with Arduino's from time to time.
I was measuring the mosfets like the other post and when I came back from a pause I noticed part of the motherboard was really hot. I remembered some of the power IC's are on the other side of the board so I went looking there. I believe a chip with marking "1285B TI 988 A5HH" get hot instantly when it gets power from the charger. This number let me to a chip from TI: TPS51285A. It matches the pin count and form factor and it does seem to step down power to 5V and 3.3V.
Now, the question is: How do I move on from here? Does it make sense that this chip causes trouble? I did try to trace the B+ rail (keep in mind this is my first guys) and up until now I couldn't find anything suspicious, until I almost burnt myself on this chip...
I want to add that the laptop didn't fail completely at once, it started by shutting down randomly until it definitely didn't want to power on again. We replaced it but it's actually still a capable laptop and I would be extremely happy if I could save it.
I'm brand new to the forum. I've found this site because I have a very similar problem like this guy. It's also a Fujitsu Lifebook and has the same symptoms: LEDs briefly flash when connecting the power adapter, battery doesn't charge. Same behaviour when connection 14.4V to the battery pins.
I have 0 experience with motherboards but I do have an electronics background, I am an electronic engineer but I have to say there's some dust on that knowledge although I play with Arduino's from time to time.
I was measuring the mosfets like the other post and when I came back from a pause I noticed part of the motherboard was really hot. I remembered some of the power IC's are on the other side of the board so I went looking there. I believe a chip with marking "1285B TI 988 A5HH" get hot instantly when it gets power from the charger. This number let me to a chip from TI: TPS51285A. It matches the pin count and form factor and it does seem to step down power to 5V and 3.3V.
Now, the question is: How do I move on from here? Does it make sense that this chip causes trouble? I did try to trace the B+ rail (keep in mind this is my first guys) and up until now I couldn't find anything suspicious, until I almost burnt myself on this chip...
I want to add that the laptop didn't fail completely at once, it started by shutting down randomly until it definitely didn't want to power on again. We replaced it but it's actually still a capable laptop and I would be extremely happy if I could save it.
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