Salem Aboshala
New Member
Last Activity: 06-19-2024, 09:45 PM
Joined: 06-11-2024
Location: M
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Hello everyone -
Good news, I started to disassemble the LCD and I discovered one cable disconnected (CNT201), just reconnected it and the backlight is working fine now.
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So many thanks [USER="295753"]mon2[/USER] for your help
Have a great dayGood news, I started to disassemble the LCD and I discovered one cable disconnected (CNT201), just reconnected it and the backlight is working fine...Leave a comment:
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I did tested the following:[LIST=1][*]Connected external 48v LED strip the PPVOUT_S0_LCDBKLT line and the booster didnt work.[*]Injected LED tester @ PPVOUT_S0_LCDBKLT with 10mAmp and there was no current drawn from Retina LED.[/LIST]Here I started to think the Retina display has a defective LED circuit and asked U7701 not to start boosting.
Is there anyway to test the Retina LED from external source ?
Any thoughts would be appreciated
Thanks- I did tested the following:[LIST=1]
- Connected external 48v LED strip the PPVOUT_S0_LCDBKLT line and the booster didnt work.
- Injected
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Thanks alot agin [USER="295753"]mon2[/USER] for your follow-ups,
Already checked = OK
I think you meant to short BKLT_SD to ground, but I shorted pin#4 & pin#6 instead to bypass 12v to PPBUS_SW_BKL, and I got what I expected at PPVOUT_S0_LCDBKLT = 12v, which means the booster still wont work.
I think U7701 still get LCD not ready for LED power on, otherwise pin#11 (BKLT_SD) should start signaling right?mon2...Leave a comment:
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Correction, [B]I2C_BKLT_SCL[/B] = [B]I2C_BKLT_SDA[/B] = 5.03v now, or maybe it is different slightly from time to time as it is a communication signals right ?Correction, [B]I2C_BKLT_SCL[/B] = [B]I2C_BKLT_SDA[/B] = 5.03v now, or maybe it is different slightly from time to time as it is a communication signals right ?Correction, [B]I2C_BKLT_SCL[/B] = [B]I2C_BKLT_SDA[/B] = 5.03v now, or maybe it is different slightly from time to time as it is a communication signals right ?Correction, [B]I2C_BKLT_SCL[/B] = [B]I2C_BKLT_SDA[/B] = 5.03v now, or maybe it is different slightly from time to timeLeave a comment:
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- [LIST=1]
- Thanks alot for your reply and greetings [USER="295753"]mon2[/USER]
- My little multimeter from Uni-T and it has auto-mode feature and it starts with sensing ac/dc voltages first, and then it starts to look for resistance if there was no voltage detected (UT123D).
- 4.78v , 5.03v and [B]EDP_IG_BKL_ON[/B]=3.33v coming via R7742 (0Ohms)
- It gives 14Kohms and then goes to 500Kohms repeatedly, I even injected external power (50v) to insure no leakage and there was 0mamps.
- Q7706: 12.66v@pin#3 , 12.76v@pin#4.[/LIST]I think Q7706 will stay off till BKLT_SD goes down right ?
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820-00138-A got image but no backlight
Dears, this is my first post here and first try to fix my own laptop Apple MacBook Pro Retina 15-inch Mid 2015.
I have some general electronics troubleshooting experience and still as my hoppy but this is my first laptop trying to fix.
History: my laptop backlight stopped working without any reason.
Symptoms:
I have image on screen using my flashlight.
I have fully working laptop with the help of my external SAMSUNG LED tv via HDMI cable.
Keyboard backlight still working and can be adjusted normally.
Since two days I tried to follow all similar... -
This is a great place to learn and share our knowledge in electronics!!!Leave a comment:
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