Hello,
So, this is my first attempt at an Apple board repair.
I have a defective board taken from an A1502 2013 13' Retina MBP.
No sign of liquid damage, no obviously burnt component. Overall board visually looks in very good shape.
Board gives a green and then orange light on the charger, but no fan spin.
I have checked the power rails, and PPBUS_G3H is present at 12.58V
All S5 power rails are present and with good voltage
Nothing on S4 power rails.
Looking at the power switching circuits, the Enable signals for PP5V_S4 and PP3V3_S4 are low.
According to the schematic, they are driven by the PCH.
Not quite sure where to look at from that point. I've seen people suggesting to look at RTC and SPI flash.
I have a good 32Khz signal on PCH_CLK32K_RTCX1.
I also looked at the SPI_CLK signal, and I can see pulses there when I apply power to the board, then a steady 3.3V
One thing I don't quite understand is who is driving this clock. Because on the schematic, there's two SPI masters on the bus - SMC and PCH, which seems weird to me.
So, this is where I am at. Hopefully the PCH is not dead. Any idea where to look at next ? Is it worth it dumping and/or reflashing the ROM ?
Thanks in advance!
So, this is my first attempt at an Apple board repair.
I have a defective board taken from an A1502 2013 13' Retina MBP.
No sign of liquid damage, no obviously burnt component. Overall board visually looks in very good shape.
Board gives a green and then orange light on the charger, but no fan spin.
I have checked the power rails, and PPBUS_G3H is present at 12.58V
All S5 power rails are present and with good voltage
Nothing on S4 power rails.
Looking at the power switching circuits, the Enable signals for PP5V_S4 and PP3V3_S4 are low.
According to the schematic, they are driven by the PCH.
Not quite sure where to look at from that point. I've seen people suggesting to look at RTC and SPI flash.
I have a good 32Khz signal on PCH_CLK32K_RTCX1.
I also looked at the SPI_CLK signal, and I can see pulses there when I apply power to the board, then a steady 3.3V
One thing I don't quite understand is who is driving this clock. Because on the schematic, there's two SPI masters on the bus - SMC and PCH, which seems weird to me.
So, this is where I am at. Hopefully the PCH is not dead. Any idea where to look at next ? Is it worth it dumping and/or reflashing the ROM ?
Thanks in advance!