820-01958 no power

[Kyle93]

Arrived with liquid damage around u7650. Before starting repair board was slightly turning on and charging battery.

After replacing U7650 and surrounding components board now only has a 12.30V PPBUS_G3H and power cycles every few seconds. Solders are good on U7650

What should be checked next?

 

[2informaticos]

Something else affected by liquid, possibly CPU, or other BGA chip.
You should inspect small resistors and traces too.

 

[Kyle93]

The resistors and traces have been inspected along with continuity testing. The minor spill occured only in the U7650 area.

PPBUS_G3H 12.33V

PP5V_S5_LDO 0.860V

 

[2informaticos]

So, you have steady 12.3V at PPBUS_G3H, or power cycling?

 

[Kyle93]

steady 12.3V at PPBUS_G3H

 

[2informaticos]

Post basic voltages for U7650.

 

[Kyle93]

P3V3MAIN_PGOOD 3.2V

P5VG3S_PGOOD 0V

 

[2informaticos]

Which schematic used in the repair process?

 

[Kyle93]

820-01521 is closest I could find

 

[2informaticos]

Post basic voltages for U7650; pins 23, 12, 13, 22, 29, 21, 4.

 

[Kyle93]

pins

23 12.34v

12 0v

13 pulsing 1.4v to 0v

22 0v

29 0.185v

21 0.011v

 

[Kyle93]

Just changed title to 820-01958. Made mistake originally in the title board number

 

[2informaticos]

Try to put it in DFU mode.

 

[Kyle93]

Even with it only drawing 20v at 0.02-0.07amps???

 

[2informaticos]

If all SLPS2R and AWAKE voltage are present, try DFU...

 

[Kyle93]

Do you have a board view for this? The 820-01521 I have has different layout.

Also noticed the board is power cycling now. T2 chip in particular is heating up then cooling down on infrared camera every few seconds.

 

[2informaticos]

No boardview, nor schematic available yet...

 

[Kyle93]

Can someone share it here?

 

[2informaticos]

Try this.

820-01521 Retina 13 2018.rar

drive.google.com

I don't have 01958.

We don't need spam here...

 

[piernov]

820-01958 MBA 13" '20 A2179 Schematics/bv request - Badcaps

www.badcaps.net