Question Is the cpu and gpu dead when almost every capacitor is shorted?

[lillehavard]

So i got a broken laptop (a hp pavillon 14 ce0006np) from a friend for free, so i checked to see if i could repair it, hoping it was just a component or ribbon cable. The laptop had been dropped and the hinges had taken some damage, but i got them off. btw, there is a "system board failure" as the charging light blinks 5 times when the battery is connected. After there were no obvious damage anywhere, I went ahead and checked for shorted capacitors to see if there were any damaged chips or the if the capacitors temselves were damaged. Whilst i havent checked the entire board yet, i checked the capacitors on the underside of the cpu and gpu. Here i encountered something strange. almost every component which i thought seemed like coupling- or normal capacitors seemed to be shorted:

Now comes the question; is this normal for the capacitors under these components or is this motherboard a lost cause?

 

[Misgar]

What exactly do you mean by "shorted capacitors". In my terminology, a shorted component is one with a very low impedance between its terminals, indicating catastrophic damage inside.

It takes a fair amount of over-voltage to destroy a non electrolytic capacitor. If those SMDs (surface mount devices) in the video are capacitors, they may well have a rating of 50V DC or 100V. At the very least they'll be 16V DC.

I only see one meter probe in the video. Is the other probe connected to chassis? Why do you think any of the capacitors are damaged? By the sounds of it the laptop died after it had been dropped. How would you recognise a dead chip if it hasn't melted? Do you have a circuit diagram or repair manual for the board?

It is quite likely that one side of the SMDs under the CPU will be connected to 0V (ground), so I'd expect to see continuity on a multimeter if you touch one side of the component. This is not the same as a short circuit. These components are deliberately connected to ground in order to do their job of reducing EMI.

I'd be inclined to look for physical damage to the motherboard around the point of impact. There might be a crack in the multi-layer PCB. Good luck with your fault finding.

 

[lillehavard]

What exactly do you mean by "shorted capacitors". In my terminology, a shorted component is one with a very low impedance between its terminals, indicating catastrophic damage inside.

It takes a fair amount of over-voltage to destroy a non electrolytic capacitor. If those SMDs (surface mount devices) in the video are capacitors, they may well have a rating of 50V DC or 100V. At the very least they'll be 16V DC.

I only see one meter probe in the video. Is the other probe connected to chassis? Why do you think any of the capacitors are damaged? By the sounds of it the laptop died after it had been dropped. How would you recognise a dead chip if it hasn't melted? Do you have a circuit diagram or repair manual for the board?

It is quite likely that one side of the SMDs under the CPU will be connected to 0V (ground), so I'd expect to see continuity on a multimeter if you touch one side of the component. This is not the same as a short circuit. These components are deliberately connected to ground in order to do their job of reducing EMI.

I'd be inclined to look for physical damage to the motherboard around the point of impact. There might be a crack in the multi-layer PCB. Good luck with your fault finding.

Yeah i might have phrased it poorly, due to me still being new to electronic stuff like smd's. I prbably didn't mean shorted capacitor, but rather checking their connection to ground. thats where the other probe is and the multimeter was on continuity test. as I have understood it in most cases (at least the ones i've encountered before) there should just be a beep on one side as just one of the ends should be connected to ground unless some other shenanigans are in the circuit.

I found a schematic for the board, but it doesnt show the actual board and its components, but rather a circuit diagram for every part on the board? i,m not really sure, but from where i've downloaded it, it said that it is used for the repairs and diagnostics of the board. this might just be how all repair schematics are, and I'm just not used to reading them like that. I have the most basic knowledge of all their symbols, but it is hard to relate any of the schematics to the actual board, for me at least.

i have found no cracks along the pcb so thats why i started checking the components. I checked the capacitors around the ic chips on the board to see if maybe i had some obvious damages to the chips. Not every time, but sometimes the fault of a chip has lead to the capacitors around it to be "Damaged" IE; both connected to ground. This was how i wanted to see if some of the chips were damaged. from what i see there are no brunt chips on the board.

So are the capacitors under the cpu and gpu emant to have both electrodes connected to ground?

 

[Misgar]

Unless you isolate the SMDs by unsoldering them, you won't be able to check if they give an open circuit reading with probes across both contacts.

The transistors inside the CPU are connected to both supply rails via other components and the positive rail is effectively shorted to ground via the ultra low impedance of the DC supply circuits. What you need is a milli-Ohm meter.

Just accept the capacitors are probably OK. If they're blackened, distorted and blobs of solder are scattered around, they're dead. If they look in good condition, chances are they're fine.

 

[lillehavard]

Then i don't really know what could be wrong with the board, as every component seems fine, no damages to the actual board, no signs of components getting ripped off and no blackened or discolored chips or other. would you have any idea what i could check next?

 

[Misgar]

It's often very difficult to work out what's wrong with a motherboard, let alone finding the components to fix it. Gone are the days when you could actually see the components without a magnifying glass and read the values. Now they're just anonymous little blobs with no markings. Unless it's a very expensive motherboard, most people will just chuck it in the bin if they don't have the expertise to fix it. Best of luck.