I am quite noob in advanced electronics, however I'm trying to fix a Sony Vaio PCG-71211M laptop mainly because I love old hardware. I don't want to send it to a technician because this computer is not important for me, I want to fix it as a hobby.
Shortly, this laptop does not display any video output when turned on, no POST, nothing. The keyboard leds are on and I can actually turn Num Locks on and off. Sometimes the laptop turns itself off straight away, sometimes, mostly after some attempts, the laptops enters a loop in which the cpu fan spins very aggressively and the CPU, GPU and the entire area gets really hot. After some time, the computer shuts itlsef down completely. I ordered a new identical cpu just because I found one online dirt cheap, but no improvements. I tried multiple ram modules, nothing. After some debugging with the help of chat gpt, I was able to measure two filter near the CPU. One of them reads a constant voltage of around 7v, the second one (the one with red dot) oscillates between 9-ish and solid 0. I tried reading the resistance of the ceramic capacitors, all that I managed to read seems fine. However, I am too noob to be able to read next the other components, mostly because I lack technical knowledge and I don't know hot to read and interpret the schematic of the board which I was able to find. chat gpt suggested there might be something wrong with the power regulators, MOSFET chips or VRMs. I feel overwhelmed at this point and don't know what to do.
any help would be really appreciated.
Comment