820-3115 wont power

Glenn

New member
Have a 820-3115 that wont power up.

Have green/orange light in magsafe
ppbus_g3h: 12.49V
PP5V_S5 : 5V

Missing s4 trace




(History the owner just told me that it died under OS install) no sign off water damage.
 

BMarden

New member
Hi Duke, I am curious. How are there pulses on PP5V_S3? Would they not get filtered by C7290, 91, 93? Would the pulse freq. be the 300KHz PWM freq? Thanks
 

Glenn

New member
I was a little careless when I turn the card, magsafen hit the network connector and that resulted in no lights in the magsafe
 

Glenn

New member
PP5V_S3 give me nothing (0.0V) on the multimeter ( I tried a couple of times)

R1800 (Pin1) 3.32V (Pin2) 3.22V
R1801 (Pin1) 3.32V (Pin2) 3.04V
R1802 (Pin1) 3.32V (Pin2) 3.31V
R1803 (Pin1) 3.31V (Pin2) 3.31V
 

dukefawks

Administrator
Also check all rails for shorts. Better to use a scope to check for power cycling or use a LED connected to 5V rails. Multimeter may be too slow.
 

Glenn

New member
No short on the s5 rails. I dont have scope so need to buy som LED tomorrow and try with.
 

dukefawks

Administrator
Also inspect closely for corrosion, these boards rarely fail on their own. Measure voltages on C1802/3 as the trace can corrode too.
Is SMC_ADAPTER_EN present?
 

Glenn

New member
No Title

Found something here.

Will measure voltages on C1802/3 and check SMC_ADAPTER_EN

now i will chek PP5V_S3 with light diode and report after
 

Attachments

  • photo900.jpg
    photo900.jpg
    4 MB · Views: 0

Glenn

New member
No Title

No pulse light on pp5v_s3

C1802 Pin 1 3.33V
C1803 Pin1 3.33V
R5085 Pin1 3.43V
 

Attachments

  • photo901.jpg
    photo901.jpg
    3.8 MB · Views: 0
Last edited:

Glenn

New member
Thank you for replay louis. It's too late i blow smc away ? Waiting for a new one. Then i will try replace u2600.

See there is missing 2 trace under smc 1 is UC and second is GND_SMC_AVSS it is 3 off thes under smc and all off them goes to the same place so is this one important?
 
Top