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820-02098 power cycling

K

Kyle93

Active member
This arrived with no liquid damage. Power cycles every few seconds. Board looks pristine. Checked all coils and do not see any shorts.

When magsafe or usb-c is plugged in they both turn on for two seconds then off then on. All voltages appear as well.

What should be checked next?
 
K

Kyle93

Active member
Same issue is occurring with F5200 removed. C5250 voltage goes to 12.30v then drops to 0V while magsafe or usb-c is plugged in as they go off and come back on
 
2informaticos

2informaticos

Administrator
Staff member
Then you may have problems on the charger side; USB-C and Magsafe areas.

I recommend to check diode mode readings around U5200 and compare with good board.
You should check Q5230/40 too.
 
K

Kyle93

Active member
Checked diode mode in those areas and all of the readings are very close to a known good board.

What should be checked next?
 
K

Kyle93

Active member
Still waiting to hear back.

Diode mode readings match a good working board. Is there anything else that can cause this issue?
 
2informaticos

2informaticos

Administrator
Staff member
Post U5200's basic voltages (keep F5200/1 removed): P_IN, AUX_DET, VDDA/P, EN_MVR, AUX_OK, A/BMON.
Any fluctuation?
 
K

Kyle93

Active member
P_IN flucuates up to 0.430v

AUX_DET 1.3V stable

VDDA/P 5V stable

EN_MVR - flucuates up to 0.465v

AUX_OK 0.056- 0.890v

A/BMON 0V
 
Last edited:
2informaticos

2informaticos

Administrator
Staff member
U8100 is not involved yet, when F5200/1 are removed.
You should get stable C5250 voltage.
If not, you have problems on U5200, or power input areas.

U8100 may be bad, but remains to test later.
 
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