A2289 - 820-01987 5V

[mushr00m]

Its a short between S and D. Sorry for my confusion

Should I replace U8200?

 

[2informaticos]

Of course...

 

[mushr00m]

I was going to replace U8200.

Removed it

But still have a short on PP3V3_G3S = 0.002V

Knowing that we still have a short on PP3V3_G3S... could U8200 be good and the problem be around these line?

How to move forward from that?

 

[2informaticos]

U8200 caused the short between 3V3_G3H_RTC and 3V3_G3S; replace it.
And find now the short to ground at 3V3_G3S.

 

[mushr00m]

Sure

Still have some questions. I should replace U8200 after solving the short on 3V3_G3S right? or it doesnt matter?

I do not have thermal camera, how to properly find this short? Injecting volts and putting some alcohol on the componentes that interconnected to 3V3_G3S? Have a better way?

How many volts can I invject? 3V directly?

 

[2informaticos]

Short's resistance is low enough to start with 1V; doesn't go over 4V anyway.

Look at boardview and localize areas with components connected to 3V3_G3S.
Then apply alcohol on them only.

No reason to change U8200 first...

 

[mushr00m]

Can I start with 3V? 2A is what my PSU also has. Is this enough? I do not feel safe to go over line voltage limit. I think I will keep it to 3V if you agree.

Sure I will follow boardview and use thinner to be honest with you! I use thinner more than alcohol

Will just put a new U8200 after solve the short!

 

[2informaticos]

What's to problem to start with just 1V???
If 3V will imply more than 2A sink on the board, your PSU will get blocked; will not inject anything, in such case.

BTW, get a 30V/20A PSU, to cover all your jobs.

 

[mushr00m]

I touhght you mention

Short resistance is low enough to start with 1V, that is, go higher at first. Am I getting you wrong?

Now you tell me to start with 1V?

Ok will start with 1V

 

[2informaticos]

Low enough resistance means you may heat something with low voltage.

 

[mushr00m]

I tried using 1V and it shows a short consuming 1.3A however went to all the components on the board and didnt find anything heating

I am using thinner instead of alcohol since it's more cost benefit down here in Brazil. Could it be the problem? Sorry that I dont have a thermal cam.

Should I increase my PSU to 2V or 3V? the amp limit of it's 3A and its already set on the max.

I will buy a stronger PSU later but I do think this one is ok to find this short.

 

[2informaticos]

OK then, increase the voltage slowly.
Stay under 3A, to not block the PSU.

 

[mushr00m]

I increased to 2V and found some heat on U6855

Removed it and guess what the short still there. Really weird

Was trying to find again on all the components connected and nothing gets heat. After removing U6855 the amp consumption with the short it's 0.350A

Should I increase now for 3V?

 

[2informaticos]

You can go up to 4V now...

 

[mushr00m]

Wento to 4V the amp consuption goes to almost 1A however nothing seems to be heating.

I already removed U8200 and U6855

Also removed C6856 thinking that could be it since I noticed U6855 heating once then it could mislead me and C6856 could be the one... but it's not

 

[2informaticos]

4W is enough power to heat something.
Did you remove CPU heatsink?

 

[mushr00m]

You meant 4V right?

Yes I removed the CPU heatsink!

 

[mushr00m]

However nothing in this line is around the cpu heatsink

 

[2informaticos]

4W is the power you generated with 4V/1A...

 

[mushr00m]

Am I doing something wrong if I dont see nothing heating?

It should heat instantly as it did with U6855 right?

Images of the areas that I am looking

PSU @ 4V/2A goes to 1.2A when shortening this line.