P775TM1 Power Supply Dying

Hello, I am having some issues with my P775TM1 and I am not sure if it’s a power supply or motherboard issue.

Basically what happens is if the battery is either dead or the battery is removed, and I plug in the laptop and power it on, the laptop power light will blink real quick, and then the power supply’s green light will go out.
I then have to unplug the power supply and plug it in again for the green light to come on again.

However, if the battery is charged and in the laptop and the laptop is plugged in to the power supply, the laptop will turn on and function correctly.

I tested the voltage coming out of the power supply, and it is the correct 19.5V.

I am just wondering if it is more likely to be a power supply issue or a motherboard issue, and if there is anything else I can try to diagnose the issue.

Thank you!

Edit: I just re-tested the power supply and it’s putting out closer to 19.2-19.3v.

 

Is that voltage under load and where are you measuring it?

 

Thanks for the reply!

I actually just went ahead and ordered a new power supply, and the same behavior is occurring.
I am unable to power on the laptop without a charged battery installed.

Should I be able to power on the machine without a battery installed?

My machine is configured with an 8700k/GTX 1080.

 

Should work fine, I've ran both my P775 and P870 w/o batteries. Just be sure to properly power down.

 

I just tested removing the battery after it's started, and it is fine. It is just the act of pressing the power button that kills the power supply.
Very strange.

 

I also just noticed that the power supply will die when I shut it down, even if it is properly shut down via Windows.

 

Sounds like your charger/power supply should be replaced before any assumption about the state of the mobo can be determined given that it shuts down so many times.

 

Yes, that was my first step. I ordered a new 330W power supply, and the same behavior is occurring. I am starting to think that it is the motherboard.

 

Can you check your motherboard on the DC-IN zone to check for cracked solder joints?

 

I got some interesting finds. So before I did a full teardown to check out the DC-IN, I just removed the GPU and tested it out.

With the GPU removed and the battery removed, and the AC adapter plugged in, the laptop starts up every time I press the button and the power supply does not turn off.

So that would point to the GPU, correct?

I visually inspected it, and other than the thermal paste, everything else looks fine. I took some pictures in case someone notices something I missed.

 

I take it you don't have a multimeter?

 

Actually yes I do have one!
I measured the resistance described in this post, and it checks out.

Is there anything else I can check?

 

Yes, next most likely to have an issue is the 5V rail. Check the resistance between the smaller set of large pads on the backside of the mxm slot

 

Thanks for replying! Is that on the motherboard? Or the backside of the MXM card?

 

Mxm card

 

Yeah those check out as well

 

So 5V was also thousands? Last would be the 3.3V. Connection for that is the double sized mxm pin on the front, far left on the mxm connector. Compare it to any ground.

 

Yep, that also looks good, strange.

 

Is it possible these problems could be caused by non genuine power supplies? Is there a way I can test them, or verify they are genuine?

 

Clevo systems do not check PSU. It either works, or it doesn't work.

 

You could open the PSU and check the topology, that's about it if the label looks genuine.

 

Turns out the power supply I purchased was not genuine. I noticed wear on the security torx screws, upon investigation I noticed some sketchy looking stuff in the actual power supply itself.

I purchased one through HID Evolution, and haven’t had any issues. Computer starts and runs without a battery, and power supply does not get tripped off.

 

It could have been a bad repair job on a bad one.