820-00281-A Only 5v and 0.26amp not turning on

[2informaticos]

So you have a problem on 3V3_G3H power rail.
Inject 3.5V there and use a performant thermal camera.
0.035 is far from short; possibly nothing gets hot.
Just try to detect what component gets a bit higher heat signature than other.

However, I recommend to inject voltage starting with 1V; increase slowly, monitoring current consumption.

 

[MeTech Turkey]

Please do not get angry if these are silly ones but I have 2 questions that I dont know the answers;
1) Do I have to keep these 3 removed caps when I am injecting the 3.5V?
2) I dont have thermal camera at home and I have no shop anymore. I heared that lighet gas can be used but I dont know if it is harmful for the logic board or not? If yes then I have to order a thermal camera and wait around 10 days to arrive. Or do you have any other suggestions?

 

[2informaticos]

What caps removed???

Alcohol tehnique doesn't help in this case.
Unless you are lucky and some chip enters in thermal avalanche.

 

[MeTech Turkey]

I mean F7000/1 and R6923 as caps removed so keep these removed then inject voltage right?

 

[2informaticos]

Of course.

BTW, these are not caps...

 

[MeTech Turkey]

I have found a thermal camera but unfortunately I cant see any shorted or heated parts. But now all the metal shileds stayed soldered I hope the problem is not under one of them but generally I dont see any heated part to be honest. So what is your advice to unsolder all the metal shields and check again or something else?

 

[2informaticos]

As I said, probably nothing gets really hot.
You need to detect small temperature difference.
Of course, metal shields don't help in this case.

BTW, remove CPU heatsink first and try again.

 

[MeTech Turkey]

I have removed the heatsink but the result is same so I think I have to remove all metal shields but what I realised from power supply when I Inject 3.5v I see the amp direct goes up to 0.03Amp but then goes down to 0.002A - 0.008A I dont know if this helps. No will try to remove metal shields and continue checking

 

[MeTech Turkey]

All the metal shields removed and heat sink removed but no chance, I have seen nothing gets hot. What is other opportunities to find this solution?

 

[2informaticos]

Still 0.035 in diode mode?

 

[MeTech Turkey]

L6900 on diode mode now 0.0617 but I still have the F7000/1 and R6923 is removed

 

[2informaticos]

That is still bad value.
Some component damaged, not easy to find.
Can be a simple capacitor (leakage), or any IC powered from this rail.

BTW, I hope you are cheking at pin 2/R6923...

 

[MeTech Turkey]

Hello and welcome back 2/R6923 is still same 0.035

I have emailed you twice about the problem you had on your website. Because thats my first profession. Im a web developer, I would like to help you to get rid of the error you had but I think you didnt see my emails. When you look at your emails my whatsapp number is there also. I will be always happy to help you when you have this kind of errors for free.

And when we get back to the problem do you advice anything else to do?

 

[2informaticos]

0.0617 is also low reading on L6900.
Lift L6900 and check where this value remains.

Really strange to get lower readings than expected on both pads of R6923, once removed.

 

[MeTech Turkey]

I removed the L6900 on the 1st leg I read 0.600 but on second leg I get OL

 

[2informaticos]

How did you get 0.0617 before???

With 0.600 on pad 1/L6900, the problem remains on the main 3V3_G3H power rail.
0.035 doesn't help to find the problem with voltage injection.
You can try isolating this rail disconnecting components (one by one); like L5001, U5165, etc.

Pay atention to J5250/60, they are prone to get corroded.

 

[MeTech Turkey]

To clarify everything
all the components removed (L6900, F7000/1 and R6923) as we talked so I read:
Diode mode:
1/L6900 - 0.630
2/L6900 - O.L
1/R6923 - O.L
2/R6923 - 0.356
With also L5001 removed
diode mode L6900 is same
removed U5165 and on diode mode 5/U5165 is 0.350 and L6900 is still same values.

What elso should I do now?

 

[2informaticos]

What happened with 0.035 and 0.0617 readings???

I told you to remove some components and check diode mode to see where these readings remain.
Now you can't find them in the previous mentioned points; really strange...

 

[MeTech Turkey]

I dont know and not sure about it but I might wrote 0.617 as 0.0617 so do you think it is better to resolder all of them and better to start from beginning? To be honest last times I had bad times and that could be my fault thats why I am asking is it better to resolder them get a 87 watt charger and try everything again? I am so sorry for your time loss, mine is not a problem.

 

[2informaticos]

Yes, resolder all and get the 87W charger.