mbcontrol
Member
This board came with water damage arround Q8400 and no backlight. Picture is present and it boots into the login-screen. The board was in terrible condition. I think it was a refurbished board from apple. the customer promised me that he bought an refurbished macbook and there was no repair. There was flux an solderballs an bad solder joints all over the board. So i made a video to safe the hints and did first an ultrasonic-cleaning. Normaly i make ultrasonic after repair, but at this board you could not see anything - i never saw something like this before.
I cleaned the water damage an changed, over hours of troubleshooting, the following parts:
U8400 (new chip), U8400 (from donor), R8450, R8451, R8452, R8453, R8432, C8412, C8413, C8414, C8475, Q8400, C8400, R8401, R8402. C8476, C8477, C5451, C5452, R8400, F8400
Other hints:
Backlight keyboard works and is dimmable with function keys.
PRAM-Reset don't work - tried many times with int. keyboard.
Display-Backlight always tested with original display in macbook and known good display from us.
I don't see any data signals on the oszi - only the dc voltage with 5.1v.
R8450-R8453 was good, but i changed it with new ones (you never know).
Here are the measurements:
I2C_BKLT_SCL = 5.1v (no data-signal on oszi)
I2C_BKLT_SDA = 5.1v (no data-signal on oszi)
ISNS_LCDBKLT_P = 13.061v
ISNS_LCDBKLT_N = 13.061v
PP5V_S0_BKLT_D = 5.109v
LCDBKLT_FET_DRV_R = 0v
LCDBKLT_SW = ca.115mV
PPVIN_SW_LCDBKLT_SW = ca.240mV
BKLT_SD = 12.879v
BKLT_EN_R = 3.3057v
PP5V_S0_BKLT_A = 5.1096v
BKLT_SENSE_OUT = 0v
LCDBKLT_FB = ca.250mV
PPVOUT_S0_LCDBKLT = ca.282mV
LCDBKLT_TB_XWR = ca.281mV
I cleaned the water damage an changed, over hours of troubleshooting, the following parts:
U8400 (new chip), U8400 (from donor), R8450, R8451, R8452, R8453, R8432, C8412, C8413, C8414, C8475, Q8400, C8400, R8401, R8402. C8476, C8477, C5451, C5452, R8400, F8400
Other hints:
Backlight keyboard works and is dimmable with function keys.
PRAM-Reset don't work - tried many times with int. keyboard.
Display-Backlight always tested with original display in macbook and known good display from us.
I don't see any data signals on the oszi - only the dc voltage with 5.1v.
R8450-R8453 was good, but i changed it with new ones (you never know).
Here are the measurements:
I2C_BKLT_SCL = 5.1v (no data-signal on oszi)
I2C_BKLT_SDA = 5.1v (no data-signal on oszi)
ISNS_LCDBKLT_P = 13.061v
ISNS_LCDBKLT_N = 13.061v
PP5V_S0_BKLT_D = 5.109v
LCDBKLT_FET_DRV_R = 0v
LCDBKLT_SW = ca.115mV
PPVIN_SW_LCDBKLT_SW = ca.240mV
BKLT_SD = 12.879v
BKLT_EN_R = 3.3057v
PP5V_S0_BKLT_A = 5.1096v
BKLT_SENSE_OUT = 0v
LCDBKLT_FB = ca.250mV
PPVOUT_S0_LCDBKLT = ca.282mV
LCDBKLT_TB_XWR = ca.281mV