820-3115-B no keyboard backlight

[Sr. Robot]

Hi, got and 820-3115-B with no keyboard backlight.

Tried good sheet no light. Pressing keyboard backlight keys show icon. Iluminating camera shows prohibition symbol.

Replaced C5855 because it had a bit of corrosion but no change.

Replaced U5850 just in case.

i get PP5V_S0 on L5850 and PP3V3_S0 on R5853.

Resistances for R5855, R5854 and R5853 have correct values.

Theres continuity between U5850 and its components.

SMC_SYS_KBDLED, KBDLED_SW, KBDLED_CAP and KBDLED_ANODE are all 0v.

 

[2informaticos]

Be sure pin 2/R5854 and pin 1/J5815 are grounded, when KB backlight flex is inserted.

 

[Sr. Robot]

Yes, both grounded with kb bl sheet connected

 

[2informaticos]

Just in case, change L5850.
I know few cases with bad coil...

 

[Sr. Robot]

Replaced L5850, now i got bl. Thanks a lot