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I suppose before I get into the details, I should provide a tl;dr. My HP Elitebook 8450p absolutely will not power on, under any circumstance.
A more detailed description of my problem:
I'm currently in a PC repair class, which mostly consists of my professor giving us a desktop that doesn't necessarily work, and making sure it works, installing a specific OS, and getting it in running order. Currently, I'm working on an HP Elitebook 8540p laptop as a side project; this is not going to be graded, it's just to learn more. He gave me the laptop, told me it doesn't turn on, and left me to my own devices. I looked it over, and sure enough, it doesn't turn on at all.
Connecting a battery or charger gives me one blinking LED, the one that represents charging. It starts blue, but immediately turns orange for a moment, turns off, then repeats. HP's given manual shows that it's not an error code.
I've confirmed that the problem is not the RAM or the CPU, as I've changed both out. I checked the charging cable for power with a multimeter, and it was giving what it needed. Going on with the multimeter, I checked different parts of the mobo. Some areas, such as the RAM slots and the WiFi adapter showed low voltage, but other areas, like the heatsink fan connector didn't give any power at all, along with all external ports, and I'm really at a loss for what the problem could be.
My teacher suggested it could be a shorted port, but I'm not sure how I could test it, or even fix it. The multimeter showed no power in them, and they're soldered directly to the mobo; they can't be changed anyways, at least within the scope of the class. My worry is that
I'm absolutely stuck on this laptop, and I was wondering if I could get some advice or ideas to try out. I think I should mention one more time, this is not a graded assignment, this is more or less for fun and to get experience with laptops; helping me actually can't change my grades. Sorry for the long post. Thanks
You did try obvious things, as powering on with battery removed and trying another known good power adapter, right? Also, check the power button if it really works. – Dan – 2015-02-21T10:21:05.413
Yes, I did all of those, even removing different parts such as RAM at a time, still no luck. Thankfully, my teacher had others of the same model lying around, I did get a chance to swap out parts like the panel with the power button. – Herpeslurpee – 2015-02-22T17:18:25.190
Then I'd say the motherboard is done (something wrong in the power control circuits). You have to check charger circuitry and various onboard regulators that power the cpu and chipset – Dan – 2015-02-22T17:56:05.680