Перейти к основному содержанию

Отремонтируйте ваше устройство

Обучение ремонту

Запчасти и инструменты

Помощь

Текущая версия: John Dupont ,

Название:

No backlight + no keyboard backlight implies fuse problem?

Текст:

I have had display problems, so I changed the backlight fuse on my Macbook Air. After that, there is still no display. The computer works fine otherwise, I can turn it on and hear sounds.
 
As of now I am wondering whether I soldered wrong, or whether the problem is with the backlight itself.
 
I also noticed that there is no keyboard backlight. Even if I hit the keyboard backlight keys, it doesn't light up.
 
I was wondering whether that means that my soldering is wrong, or not. Is the backlight fuse also "protecting" the keyboard backlight ?
I was wondering whether that means that my soldering is wrong, or not. Is the backlight fuse also "protecting" the keyboard backlight ?
 
EDIT: I did some measurements on the logic board. My interpretation of them is that everything seems fine, except the voltage divider for BKL_EN. For some reason, even though input voltage seems fine, and both resistors have correct resistance, divider output is slightly lower than it should be.
 
The only weird thing I notice, that could explain this value, is the fact that resistance rises slowly when I measure it. It starts at half the final value, and rises logarithmically for about 30 seconds.
 
Here are the measurements:
 
Global values
* PPBUS_G3H : 8.3V
* SMC_LID : 3.4 V
 
Driver output
* PPVOUT_SW_LCDBKLT : 8.43 V
* PPVOUT_SW_LCDBKLT_FB (at test point) : 8.4 V
* PPBUS_SW_LCDBKLT_PWR_SW : 8.46 V
* SMC_LIDPPBUS_SW_BKL (before L9701 inductance) : 3.48.32 V
* PP5V_S0_BKLOutput of inductance
** When measured in DC
: 5.178.32 V
* PP3V3_S0_BKL_VDDIO

** When measured in AC
: 3.317.5 V
* BKL_PWM : 3.34 V
* LCD_BKL_PWM : 3.34 V
Feedback line connectivity check:
** By putting multimeter in diode mode, placing red probe on ground, and black probe on PPVOUT_SW_LCDBKLT, multimeter displays 510/512/515
*** A second measurement gave 530

BKL_EN circuit
* SMC_LIDPPBUS_SW_BKL (before L9701 inductance) : 3.48.32 V
* PP5V_S0_BKLOutput of inductance
** When measured in DC
: 5.178.32 V
* PP3V3_S0_BKL_VDDIO

** When measured in AC
: 3.317.5 V
* BKL_PWM : 3.34 V
* LCD_BKL_PWM : 3.34 V
Feedback line connectivity check:
** By putting multimeter in diode mode, placing red probe on ground, and black probe on PPVOUT_SW_LCDBKLT, multimeter displays 510/512/515
*** A second measurement gave 530

BKL_EN circuit
* BKL_EN : 2.64 V
* PPBUS_SW_LCDBKLT_PWR : 8.43 V
** measured both at test point, and on resistor closest to driver
* Fuse : 8.43 V
* Resistors
** R9731 : 199.9 kOhm201 kOhms
** R9715 : 95.6 kOhm101 kOhms
** R9731 : 199.9 kOhm201 kOhms
** R9715 : 95.6 kOhm101 kOhms
** => theoretically BKL_EN should be : 2,72
* Feedback line connectivity check:
** By putting multimeter in diode mode, placing red probe on ground, and black probe on PPVOUT_SW_LCDBKLT, multimeter displays 500 when computer is off, -600 when it is on
*** A second measurement gave 530
 
Other ourputdriver inputs
* PP5V_S0_BKL : 5.17 V
* PP3V3_S0_BKL_VDDIO : 3.3 V
* BKL_PWM : 3.34 V
* LCD_BKL_PWM : 3.34 V

LCD activation circuit
* PP3V3_SW_LCD : 3.25 V

Other output
Other ourputdriver inputs
* PP5V_S0_BKL : 5.17 V
* PP3V3_S0_BKL_VDDIO : 3.3 V
* BKL_PWM : 3.34 V
* LCD_BKL_PWM : 3.34 V

LCD activation circuit
* PP3V3_SW_LCD : 3.25 V

Other output
* LED_RETURN_1 : 0V
* BKL_ISEN_1 : 0V
* LED_RETURN_2 : 0V
* BKL_ISEN_2 : 0V
* LED_RETURN_3 : 0V
* BKL_ISEN_3 0V
* LED_RETURN_4 : 0V
* BKL_ISEN_4 0V
* LED_RETURN_5 : 0V
* BKL_ISEN_5 0V
* LED_RETURN_6 : 0.5 V
* BKL_ISEN_6 : 0.5V
 
Other BKL_EN measurements
* measurement 2
** PPBUS_SW_LCDBKLT_PWR 8,3
** R9731 : 195
** R9715 : 96
** BKL_END : 2,6
** Theoretically BKL_EN should be 2,74
* measurement 3
** BKL_EN : 2.65 V
** PPBUS_SW_LCDBKLT_PWR 8,5
* measurement 4
** BKL_EN : 2.59 V
** PPBUS_SW_LCDBKLT_PWR 8,31

Устройство:

MacBook Air 13" Mid 2011

Статус:

open

Принятый ответ:

389890

Отредактировано: John Dupont ,

Название:

No backlight + no keyboard backlight implies fuse problem?

Текст:

I have had display problems, so I changed the backlight fuse on my Macbook Air. After that, there is still no display. The computer works fine otherwise, I can turn it on and hear sounds.
 
As of now I am wondering whether I soldered wrong, or whether the problem is with the backlight itself.
 
I also noticed that there is no keyboard backlight. Even if I hit the keyboard backlight keys, it doesn't light up.
 
I was wondering whether that means that my soldering is wrong, or not. Is the backlight fuse also "protecting" the keyboard backlight ?

EDIT: I did some measurements on the logic board. My interpretation of them is that everything seems fine, except the voltage divider for BKL_EN. For some reason, even though input voltage seems fine, and both resistors have correct resistance, divider output is slightly lower than it should be.

The only weird thing I notice, that could explain this value, is the fact that resistance rises slowly when I measure it. It starts at half the final value, and rises logarithmically for about 30 seconds.

Here are the measurements:
* PPBUS_G3H : 8.3V
* PPVOUT_SW_LCDBKLT : 8.43 V
* PPVOUT_SW_LCDBKLT_FB (at test point) : 8.4 V
* PPBUS_SW_LCDBKLT_PWR_SW : 8.46 V
* SMC_LID : 3.4 V
* PP5V_S0_BKL : 5.17 V
* PP3V3_S0_BKL_VDDIO : 3.3 V
* BKL_PWM : 3.34 V
* LCD_BKL_PWM : 3.34 V
* BKL_EN : 2.64 V
* PPBUS_SW_LCDBKLT_PWR : 8.43 V
* Fuse : 8.43 V
* Resistors
** R9731 : 199.9 kOhm
** R9715 : 95.6 kOhm
** => theoretically BKL_EN should be : 2,72
* Feedback line connectivity check:
** By putting multimeter in diode mode, placing red probe on ground, and black probe on PPVOUT_SW_LCDBKLT, multimeter displays 500 when computer is off, -600 when it is on
*** A second measurement gave 530

Other ourput
* LED_RETURN_1 : 0V
* BKL_ISEN_1 : 0V
* LED_RETURN_2 : 0V
* BKL_ISEN_2 : 0V
* LED_RETURN_3 : 0V
* BKL_ISEN_3 0V
* LED_RETURN_4 : 0V
* BKL_ISEN_4 0V
* LED_RETURN_5 : 0V
* BKL_ISEN_5 0V
* LED_RETURN_6 : 0.5 V
* BKL_ISEN_6 : 0.5V

Other BKL_EN measurements
* measurement 2
** PPBUS_SW_LCDBKLT_PWR 8,3
** R9731 : 195
** R9715 : 96
** BKL_END : 2,6
** Theoretically BKL_EN should be 2,74
* measurement 3
** BKL_EN : 2.65 V
** PPBUS_SW_LCDBKLT_PWR 8,5
* measurement 4
** BKL_EN : 2.59 V
** PPBUS_SW_LCDBKLT_PWR 8,31
I was wondering whether that means that my soldering is wrong, or not. Is the backlight fuse also "protecting" the keyboard backlight ?

EDIT: I did some measurements on the logic board. My interpretation of them is that everything seems fine, except the voltage divider for BKL_EN. For some reason, even though input voltage seems fine, and both resistors have correct resistance, divider output is slightly lower than it should be.

The only weird thing I notice, that could explain this value, is the fact that resistance rises slowly when I measure it. It starts at half the final value, and rises logarithmically for about 30 seconds.

Here are the measurements:
* PPBUS_G3H : 8.3V
* PPVOUT_SW_LCDBKLT : 8.43 V
* PPVOUT_SW_LCDBKLT_FB (at test point) : 8.4 V
* PPBUS_SW_LCDBKLT_PWR_SW : 8.46 V
* SMC_LID : 3.4 V
* PP5V_S0_BKL : 5.17 V
* PP3V3_S0_BKL_VDDIO : 3.3 V
* BKL_PWM : 3.34 V
* LCD_BKL_PWM : 3.34 V
* BKL_EN : 2.64 V
* PPBUS_SW_LCDBKLT_PWR : 8.43 V
* Fuse : 8.43 V
* Resistors
** R9731 : 199.9 kOhm
** R9715 : 95.6 kOhm
** => theoretically BKL_EN should be : 2,72
* Feedback line connectivity check:
** By putting multimeter in diode mode, placing red probe on ground, and black probe on PPVOUT_SW_LCDBKLT, multimeter displays 500 when computer is off, -600 when it is on
*** A second measurement gave 530

Other ourput
* LED_RETURN_1 : 0V
* BKL_ISEN_1 : 0V
* LED_RETURN_2 : 0V
* BKL_ISEN_2 : 0V
* LED_RETURN_3 : 0V
* BKL_ISEN_3 0V
* LED_RETURN_4 : 0V
* BKL_ISEN_4 0V
* LED_RETURN_5 : 0V
* BKL_ISEN_5 0V
* LED_RETURN_6 : 0.5 V
* BKL_ISEN_6 : 0.5V

Other BKL_EN measurements
* measurement 2
** PPBUS_SW_LCDBKLT_PWR 8,3
** R9731 : 195
** R9715 : 96
** BKL_END : 2,6
** Theoretically BKL_EN should be 2,74
* measurement 3
** BKL_EN : 2.65 V
** PPBUS_SW_LCDBKLT_PWR 8,5
* measurement 4
** BKL_EN : 2.59 V
** PPBUS_SW_LCDBKLT_PWR 8,31

Устройство:

MacBook Air 13" Mid 2011

Статус:

open

Принятый ответ:

389890

Отредактировано: oldturkey03 (подробности голоса) ,

Название:

No backlight + no keyboard backlight implies fuse problem?

Текст:

I have had display problems, so I changed the backlight fuse on my Macbook Air. After that, there is still no display. The computer works fine otherwise, I can turn it on and hear sounds.

As of now I am wondering whether I soldered wrong, or whether the problem is with the backlight itself.

I also noticed that there is no keyboard backlight. Even if I hit the keyboard backlight keys, it doesn't light up.

I was wondering whether that means that my soldering is wrong, or not. Is the backlight fuse also "protecting" the keyboard backlight ?

Устройство:

MacBook Air 13" Mid 2011

Статус:

open

Принятый ответ:

389890

Оригинальный сообщение: John Dupont ,

Название:

No backlight + no keyboard backlight implies fuse problem?

Текст:

I have had display problems, so I changed the backlight fuse on my Macbook Air. After that, there is still no display. The computer works fine otherwise, I can turn it on and hear sounds.

As of now I am wondering whether I soldered wrong, or whether the problem is with the backlight itself.

I also noticed that there is no keyboard backlight. Even if I hit the keyboard backlight keys, it doesn't light up.

I was wondering whether that means that my soldering is wrong, or not. Is the backlight fuse also "protecting" the keyboard backlight ?

Устройство:

MacBook Air 13" Mid 2011

Статус:

open