(347) 552-2258 [email protected]

820-3115 - No Backlight

Palhano

Palhano

Member
This plate came dead. After replacing some oxidized components, traditional resistor R5481 and I did Rebaling in SMC because of the oxidation. It returned to normal, in the tests the BKL stopped!

Test with another screen - ok
Checked Trails - Ok
F9700 - Ok
D9701 - Post-diode p2 .607 - P1 .405 - With and without screen
D9701 - P2 12.5V - P1 12.56V

Q9706 - 1, 2, 4, 5 and 6 - 12.56V / 3 - 4V
L9008 / L9004 - 3.27V - Both pins
 
2informaticos

2informaticos

Administrator
Staff member
"Test with another screen - ok"
What this means, do you get vacklight with other screen???
I suppose not, but is not the correct way to say that!

Post BKL_EN/PWM levels; be sure R9704 is good.
Do PRAM reset 2-3 times.
 
Palhano

Palhano

Member
Excuse me. The idea was that he had already tested with another screen.

R9704 is good!
BKL_EN - 2.9V
BKL_PWM - 0V (bad sign?)

I had already checked reset PRAM!
 
2informaticos

2informaticos

Administrator
Staff member
Remove R9704 and run wire from C9704 to R9715.
If backlight comes on, test the machine few hours; then rebuild original circuit and check again BKL_PWM.
 
Palhano

Palhano

Member
Rebuild the circuit, stopped the BKL. I used components from another board.

I noticed that the power button stopped working to turn on. If you try to turn off by pressing, it works.
 
2informaticos

2informaticos

Administrator
Staff member
PCH problems probably.

Trigger SMC_ONOFF_L and check for pulse at PM_SLP_S4_L, at same time.
Check all PCH's RTC signals.
 
Palhano

Palhano

Member
I don't have a pulse on PM_SLP_S4_L when I try SMC_ONOFF_L!

RTC_RESET_L - 3.26V
PCH_INTRUDER_L - 1.65v (problem, no?)
PCH_INTVRMEN - 2.5v
PCH_SRTCRST_L - 3.26V

PPVRTC_G3H - 3.3V
 
2informaticos

2informaticos

Administrator
Staff member
PCH_INTRUDER_L still low?
If yes, heat PCH area with quality flux.
May have luck to be caused by accumulated crap underneath PCH.
 
Palhano

Palhano

Member
PCH_INTRUDER_L is at 3v now. but still without pulse in PM_SLP_S4_L, triggering SMC_ONOFF_L. Also without BKL.
 
2informaticos

2informaticos

Administrator
Staff member
Heat reaction may be caused by accumulated crap, or PCH internal issue:
Missing PM_SLP_S4_L points to PCH problem; seems to be generated only when charger is plugged in.
But you need to confirm signals from SMC toPCH first.

Did you check PM_SLP_S4_L for pulse at same time when trigger SMC_ONOFF_L?
Be sure to have drop pulse at PM_PWRBTN_L also.
 
Palhano

Palhano

Member
I tried to heat the PCH, I also put it in the tub to clean! Unsuccessfully!

Exactly, only have the signal PM_SLP_S4_L with charger. Triggering the SMC_ONOFF_L, I don't have a pulse. I'm testing with the battery, the power button and SMC_ONOFF_L don't turn off the board. So I put the battery in and try to trigger SMC_ONOFF_L.

I will check SMC signals to PCH, can it be SMC bad?

PM_PWRBTN_L always 3.4v, no drop.
 
2informaticos

2informaticos

Administrator
Staff member
"Exactly, only have the signal PM_SLP_S4_L with charger"
Do you mean PM_SLP_S4_L is high when you connect the charger?
 
You must log in or register to reply here.
Top