Macbook Pro 13 A1502 (820-4924)

[Ciki]

Turn on but have beeps so I remove u7400 and found that have short on C7401 which is PP1v35_s3 and c7425 DDRREG_LL also showing short ,even I removed Q7430

 

[aprendiz]

Have beeps? how many beeps?
C7401 is on 1.2V line wich is the output of U7400, what do you mean by short??? How many ohms???

 

[Ciki]

3beep then pause and 3beeps again c7401 resistance to ground 0.001

 

[Ciki]

I inject 1.35V on pin 2 L7430 and reading is 0.08V and 4.4A current but cant feel any heating elements ,when injected 1.35V on pin 1 L7430 no short getting normal 1.35V and 0.00A current

 

[dukefawks]

That seems like a "hard" short. Either inside the board or someone "reflowed" something and now there is a shorts under the RAM or CPU.

 

[Ciki]

I think CPU is ok because all power rail to CPU is present

 

[dukefawks]

Don't think I can help with this as we know what is wrong already. I say someone messed with the board and created a short by reflowing something and shorting out some balls under CPU/RAM.

 

[Ciki]

I removed RAM and short is gone now I have to resolder back (nightmare) need stencils because the solder balls to small now for solder ,each ram have some kind of raised barrier in middle