820-4924 - PP5V_S0/S3 Missing

pws6074

New member
Guys,

The board has water damage.
The thing is "works" (turn on, get the login screen, but the keyboard and tracks doesn't), bc the board looks like a S****, i decide before start troubleshooting drop on the supersonicmachine.
Well, after that, the PP5V_S0 /S3 is missing.

Any hint at this point?
 

TCRScircuit

Super Moderator
Staff member
Ultrasonic cleaner. Never clean a board before prefroming localized reflows of the damaged areas.
 

pws6074

New member
Yes, for sure. Like i said: After the USC, the S0/S3 is missing, but S5 still there.
SMC_RESET is there 3.4 i get green light
 
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pws6074

New member
u1950
Pin 1 = 0
Pin 2 = 0.90v
Pin 3 = 0
Pin 4 = GND
Pin 5 = 0
Pin 6 = 0
Pin 7 = 0
Pin 8 = 3.4V

u1900
Pin 1 = 3.3V
Pin 2 = 3.3V
Pin 3 = 0V
Pin 4 = 0.90V
Pin 5 = 3.34V
Pin 6 = 3.34V
Pin 7 = 0V
Pin 8 = 0V
Pin 12 = 0.4V
Pin 13 = 3.4V
Pin 14 = 0V
Pin 15 = 0V
Pin 16 = 0V

u6100
Pin 1 = 0V
Pin 2 = 3.34V
Pin 3 = 3.34V
Pin 4 = 0V
Pin 5 = 3.34V
Pin 6 = 3.34V
Pin 7 = 3.34V
Pin 8 = 3.34V
 
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dukefawks

Administrator
By checking I meant for corrosion. Check if board is power cycling on L7520 preferably with a scope as multimeter can be to slow to catch the pulse.
 

dukefawks

Administrator
If you don't want to spend any money go find some old CRT scope for $20. Any 10MHz piece of crap will suffice.
 

pws6074

New member
Duke, i found a corrosion on Pin 4 ( PPVOUT_S0_KBDBKLT ) J9515, so i removed.
Right now, i get my 5v back.
So, i tested PPVOUT_S0_KBDBKLT PIN 4-3 short to ground, for see if i get some, and then the multimiter shows me 2.4 Ω.
So i start remove the component one by one, but i still get 2.4.

Any ideia?
Thank you for all your help
 

dukefawks

Administrator
Usually in the KBD keyboard connector or in the board in that area. Is the board Chiming and working again, KBD backlight is not critical of course. Can take out D7720 to isolate the short and have the rest of the machine work.
 

pws6074

New member
The board works now. However, the system can't recognize the battery. I try another battery and i get the same thing.
I try to fix without ask you guys, but i'm stuck on this.
Any hint?

Thank you
 
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