HP laptop doesn't power up

petvanhun

Reputable
Oct 24, 2014
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4,510
Dear Fellow Users,

I am kindly asking for your help. I have an HP DV7T-6C00 laptop which doesn't power up at all. I have read various forum threads and they did not solve my problem that's why I'm opening a new one.

It started about two weeks ago, when it didn't want to wake up from sleeping, only after removing battery and plugging the charger in. It seemed odd, so I did backup from everything. Ever since then it does not power up at all.

When I plug the charger in (without battery), the charger indicator light is on with a steady white. If battery is in the result the same. If I have the battery disconnected from the laptop for a while, the light is orange (meaning that it's charging) and it becomes white (meaning that it's fully charged).

I tried various solutions to solve the problem, including the following:
- disconnecting every external device
- power up with only battery,
- power up without battery but with charger,
- hard reset (for 15 sec, 30 sec, 2 mins holding the power button),
- removing one RAM module, another and both,
- removing hard drive,
- removing optical drive,
- checking ZIF connectors,
- holding the power button for 15 sec.

No fan sound, no beep sounds, no emergency LEDs (Caps Lock and Num Lock), nothing except for the charger indicator light. Also, I can feel the power button is working.

I happen to have a multimeter and with that I was able to exclude the charger as a possible cause since its voltage is within norm.

I have two guesses: the motherboard and the CPU. Unfortunately I have no replacing capabilities to check them without being sure which is the cause.

The challenge is open for everyone, thank you for your answers in advance.
 

plaintuts

Admirable
You will need to disassemble the laptop Then check if the heatsink fan is still functional...

Or if the ic inverter is not burnt or damaged (the pcb connected to the adapter pin for the charger)

Since you already tried removing the hdd then booting up, the main board is not responding, it should have prompt the bios for flashing.
 

petvanhun

Reputable
Oct 24, 2014
7
0
4,510


Thanks for replying.

I'll give it a shot right now, when finished, will share the results.

 

petvanhun

Reputable
Oct 24, 2014
7
0
4,510


The laptop is disassembled, how can I check whether the heatsink fan is functional?
I cannot see any burn-related or any other kind of damage.
Even though I didn't mentioned, I had already tried clearing BIOS with no result.
However, I noticed that when I plug the charger in the light suddenly fades for a second and starts to glow again. Could this be important?
 

petvanhun

Reputable
Oct 24, 2014
7
0
4,510
Well, well...I thought it won't be solved, but life is funny (and it still isn't).

I've tried accidentally with another (a third one which has almost the same voltage but almost half Amper) charger - it turned on! It did even restart with a Ctrl+Alt+Del combo. However, after I turned it off (with the power button, because there were no HDD in it), it did not want to power up again.
Somehow, I managed to find a way with hard resetting, changing adapter and taking the battery out and putting back it, to power it up. I played it three times.
Now, I am a bit confused and awaiting for your wisdom and advice.

Thanks!