Solved! Laptop won't boot up

Dec 22, 2019
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HP Compaq Presario CQ50-107NR

Basically the laptop won't boot up at all. Most of the time, I connect the charger and the LED on the charging port lights up, but pressing the power button does nothing. Sometimes, very rarely, the Wi-Fi button also lights up (orange color) (but the power button is still dim) and I hear a buzzing noise on the motherboard, but the power button still does nothing. I tried disassembling it to check for problems and I think the buzzing noise comes from a small "TPS51125 83k" chip, which also seems to heat up a lot, but I've got no clue what to do.

I tried disconnecting the battery & charger and holding down the power button, removing one or both RAM sticks, removing the hard drive, Wi-Fi adapter etc, nothing worked. I thought the power board was at fault, so I tried "jump starting" it, by touching the pins where the power board's cable connects with a thin screwdriver, but all I hear is two different buzzing noises when in contact and no other response.
 
Solution
If you are getting any lights and getting sounds inside, it may actually be on and just the display isn't.

Try this...
  1. Turn the laptop off (not sleep or hibernate but off).
  2. Connect an external monitor to the laptop.
  3. Turn on the external monitor.
  4. Turn on the laptop.
NOTE: You may have to press an "external monitor" button. Could be the f4 button or a button with two monitors on it, for the external monitor to work.

If you can see fine on the external monitor, then your attached display, or the ribbon cable that connects it, are your problem.

If you can't see on the external monitor at all either, then I would have the laptop looked at. Either by the manufacturer (if under warranty) or a local tech if not.
If you are getting any lights and getting sounds inside, it may actually be on and just the display isn't.

Try this...
  1. Turn the laptop off (not sleep or hibernate but off).
  2. Connect an external monitor to the laptop.
  3. Turn on the external monitor.
  4. Turn on the laptop.
NOTE: You may have to press an "external monitor" button. Could be the f4 button or a button with two monitors on it, for the external monitor to work.

If you can see fine on the external monitor, then your attached display, or the ribbon cable that connects it, are your problem.

If you can't see on the external monitor at all either, then I would have the laptop looked at. Either by the manufacturer (if under warranty) or a local tech if not.
 
Solution