Question What/where can I test to see if the motherboard is faulty ?

[VermilionNeko]

Hi

At one point, whilst trying to sort out a laptop, everything appeared to be fine. Now, whenever I try to boot the machine, it turns off after a few minutes. It doesn’t just shut down, it just turns off completely. The screen goes black and the green light goes orange. I have a multimeter, which I’m still fairly new to using.

Are there any areas on the motherboard I should try testing to see if it’s faulty? I mean, it’s receiving power as the light comes on, whether orange or green.

Also, for some reason, the power button no longer works. Blue lights are showing on the little board, so the connection/cable is working, but the button doesn’t respond to presses. It doesn’t turn on/off when pressing it or holding it down.

Thanks

 

[Lutfij]

You're going to have to rely on a microscope and inspect the entire PCB for a blown or burnt component on the motherboard. If nothing visually stands out, you're going to have to use a multimeter to narrow down a short(check randomly around the power delivery area and then the VRM area of the laptop). If that's inconclusive, then you use voltage injection.

Could also be a corrupt BIOS and being in BIOS recovery mode, then again you didn't mention the make, model and SKU for the laptop you're dealing with.

 

[VermilionNeko]

You're going to have to rely on a microscope and inspect the entire PCB for a blown or burnt component on the motherboard. If nothing visually stands out, you're going to have to use a multimeter to narrow down a short(check randomly around the power delivery area and then the VRM area of the laptop). If that's inconclusive, then you use voltage injection.

Could also be a corrupt BIOS and being in BIOS recovery mode, then again you didn't mention the make, model and SKU for the laptop you're dealing with.

Well, this is a fairly old laptop. From 2016. A Clevo W650RC. I'm guessing, from what I can see, the SKU number is NKW650RC0006B00146. The last digit could be a 0, I can't quite tell as the label is worn.

I've not done a voltage injection before. I presume that is an option on the multimeter?

I can't see anything out of the ordinary. Nothing looks to have blown or is bulging.

https://imgur.com/a/wv0kfwk

https://imgur.com/a/ljDkhW4

 

[VermilionNeko]

I'm not sure if it's normal or I'm doing something wrong... I've checked the power from the power supply with the multimeter and that's fine. That's around 19.65V. I've connected the power cable into the side of the laptop and then plugged the power connector into the motherboard. Placed the black lead on the ground and then tested the other three plates...? Two come up with readings that fluctuate and go back to 0, but the third doesn't come up with anything.

https://imgur.com/a/nLP8Qe9

 

[VermilionNeko]

Can someone clarify if this assumption is correct? The small board that has the power button looks to be knackered. One light comes on, which is receiving voltage, but the light on the left and right of it don't come on. The one on the left can be intermittent. The light for the power button doesn't come on at all and pressing the button doesn't do anything. So it looks to be a given that that board needs replacing. Would that be the cause of the laptop switching off? Would its faultiness directly affect the rest of the board retaining power and staying on? Because if that it is responsible then that narrows the issue down.