MacBook A1278 820-2936-B SATA HDD Not Detected

[j5p332]

Hello,

I was asked to look at a coworker's A1278 MacBook. Logic board is 820-2936-B. The laptop boots to question mark. Drive mounts fine on another MacBook, tried a new SSD with the same result. Pins in the drive end of the flex appear to be in good condition. Inside of the device was very dusty with lots and lots of cat hair.

Recommendations on what to check would be most appreciated. I have a microscope, oscilloscope, budget fluke multimeter and soldering station on hand. Some additional items such as a bench multimeter, frequency counter, vsa at home that could be brought in.

Thank you so much,

Justin

[Stevedb]

Re: MacBook A1278 820-2936-B SATA HDD Not Detected

Did you try another hdd flex i got the same problem couldn't see any damage measure the flex and all was good but still the flex was bad tried another and the hdd was recognized.

[piernov]

Re: MacBook A1278 820-2936-B SATA HDD Not Detected

Tried PRAM reset? Any liquid damage?
Drive doesn't show up at all in Disk Utility (even after changing view mode to all devices/partitions rather than just volumes) when booted in Internet Recovery or from USB installer?
If drive doesn't show up at all, try another SATA cable.

[Abu Ali]

Re: MacBook A1278 820-2936-B SATA HDD Not Detected

The HDD flex cable is well known problem on these A1278 models.

It has a sharp 90 degrees bend where it is screwed to the chassis. When the HDD uses high current for the life of it, it get damaged at this point.