820-01521 no backlight after close/open lid

[2informaticos]

Then SMC_LID_RIGHT shoud go low, when lid is closed.
If not, the corresponding hall sensor is bad.

 

[mbcontrol]

can you tell me where the hall sensor is? on the audio-board or in the speaker-model.

 

[2informaticos]

On the lid bezel should be placed a magnet which go close to the hall sensor area, when lid is closed.
Find the magnet position with a screwdriver.

 

[mbcontrol]

I found it - it's in the speaker case - I broke one to see.
I changed the audio board, the speaker/hall-sensor and the flex to the MLB two times with known good parts.

 

[2informaticos]

"Then SMC_LID_RIGHT shoud go low, when lid is closed."
Checked it?

 

[mbcontrol]

Yes, when lid is closed SMC_LID_RIGHT is low (measured at Pin1 of R4805)
when it's opened SMC_LID_RIGHT is 1,801V.

I also checked SMC_LID_LEFT (measured at Pin1 of R4804)
same values

 

[2informaticos]

This confirm a problem with T2 on that signal...

 

[2informaticos]

I forgot to ask, IPD_LID_OPEN works too?

 

[mbcontrol]

IPD_LID_OPEN is always high :-(
I changed the U4802 two times from Donor. Maybe they was both bad? Or could there be another problem with IPD_LID_OPEN?

 

[2informaticos]

U4802 MUST pull down its output, when both inputs are low.
Check surrounding traces.
Disconnect J6700 and check again.

 

[mbcontrol]

Disconnecting J6700 had no effect - still 1.8V (open and closed).
The traces arround U4802 are ok - but i'll have a look again

 

[2informaticos]

Replace U4802 again, just in case.
Be sure to use correct (OR) chip; both inputs must be low, to get output low.

 

[mbcontrol]

replaced U4802 again (from Donor 820-00426 U8170)
whatever i measured before when i told you that SMC_LID_RIGHT is low when lid is closed ??!!!
Now i have 1,409V as low-signal (measured at R4801 Pin2) and 1.518V as high-signal.

I can't find the reason for SMC_LID_RIGHT not going low. Could it have to do with the T2-Problem? It's the line we was going down from 1M to 1K with R4801.

 

[2informaticos]

It should go low when right hall sensor is activated.
That happens when the magnet from the lid go close to the sensor.