Level 1

101 points

Diagnosing MacBook Pro Hard Drive Cable Failure

I've been fixing Macs professionally (not through Apple) for well over a decade now. By far the most common thing I do is replace failing hard drives. While Apple's own tools (hardware test, Disk Utility) do almost nothing to positively confirm a failing hard drive, there are several other tools (SoftRaid, SMART Utility) that can read the SMART data and tell you for sure that a drive is failing. So unlike the Genius bar, I can quickly diagnose a bad hard drive without having to infer the problem through symptoms.

But one problem that I've noticed really being on the rise lately, is a failing hard drive cable in MacBook Pros. That's the little flat ribbon cable that connects the hard drive to the logic board. It also connects the sleep light. This is a much harder problem to diagnose, because it generally acts just like a system with a failing hard drive, but the drive will pass a real SMART test with flying colors. You might think "come on, how often does a simple cable really go bad?" Well, I've never had a traditional desktop style SATA cable go bad. But I've replaced a lot of these drive cables and I'm doing another one tomorrow. I never really know if it's going to fix the problem or not though...

... because, there's no way to directly confirm the cable is the problem. I know all about Apple service procedure. I know the official way to diagnose a problem is to start replacing parts until the computer is fixed, and that last part was your problem. But that's not how things go in the out-of-warranty world of independent Mac repair.

So I got to thinking. Computers with bad cables don't crash, or freeze. They just hang for a while randomly, then come back. JUST like a hard drive with lots of bad blocks. So what could be causing this? The only thing I can think of is SATA bus errors that only happen intermittently (on a scale relative to the amount of i/o calls a hard drive does). If that is the case, then there must be SOME kind of utility somewhere that can see these errors? There are plenty of utilities out that that have fancy 3D interfaces, but do absolutely nothing (tech tool etc). But there are a few tools that the Pros use that actually DO stuff. DiskWarrior and SMART Utility are the main tools. If I could find something that can somehow easily and definitively sniff out these bad SATA cables, that would make my life a whole lot easier.

Posted on Dec 20, 2016 4:44 AM

Top-ranking reply

IanD1953

Level 1

50 points

Posted on Oct 3, 2017 6:38 PM

I bought my MacBook Pro mid 2012 version back in August 2013 and I am just replaced the HDD cable for the third time.

I had kept the three old cables so I decided to find out what had gone wrong with them. There are 5 thin copper tacks, which connect to the 7 pin side of the SATA connector. I used a multimeter to do a continuity test on these tracks. I found that on all three cables one of these tracks had broken at the same place. The cable does a tight right angle bend at the point it passes over the optic drive. The cable flexes at this point and eventually one of the copper tracks breaks. I found that if I flexed the cable at this point the track would make and break contact.

On later versions of the MacBook Pro Apple modified the HDD mount so it would prevent the case from pressing on the HDD cable. They also introduced an upgraded cable 821-2049-A, which replaced the original 821-1480-A. Unfortunately, upgraded cable still eventually breaks. This time I have taped the cable to the optic drive to try and prevent it flexing. Time will tell if this helps. The cables are quite easy to replace and I keep a few in stock.

One way of partially checking the problem is to externally connect the HDD (e.g. use a dock or SATA to USB cable) and see if the MacBook boots correctly. You need to hold the alt key down when starting the MacBook to be able to select the external drive.

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62 replies

y_p_w

Level 6

17,762 points

Mar 11, 2018 9:47 AM in response to Grant Bennet-Alder

Grant Bennet-Alder wrote:

This issue is extremely unlikely to be a connector tolerance problem. As long as the cable is pressed firmly into place, it his self-aligning.

Connector pins could become bent/shorted though.

IanD1953

Level 1

50 points

Mar 11, 2018 5:51 PM in response to y_p_w

Thanks for that. Out of interest I took a photo of the connector on a new Apple cable. There is not much difference. The interesting thing is that connector contacts on a broken cables I bought on ebay doesn't appear to be gold plated. That cable only lasted 2 months so I wonder if it was genuine Apple cable.

RMFT76

Level 1

4 points

Apr 17, 2018 2:58 AM in response to jhannad

I've just had this problem for the first time with my mid-2012 MacBook Pro. I took it into the Apple Store in Southampton, where I bought it, and they repaired it for free there and then under 'consumer law' within half an hour.

y_p_w

Level 6

17,762 points

Apr 17, 2018 11:17 AM in response to RMFT76

RMFT76 wrote:

I got the impression that Apple had accepted there was something of a design fault with this cable and that at one time they had a policy of replacing it for free and although that policy had expired, as a gesture of good will, they were prepared to honour it in my case.

That sounds like they did the right thing. However, I'm wondering how it might affect those with older MBPs that Apple considers "vintage". The part is basically the same.

The whole set of laws/regulation under the EU/UK seem more or less toothless. Doesn't the statutory 5 to 6 year warranty in the UK say that the defect had to be present at delivery? So something just wearing out after the warranty is over doesn't apply. Also, the responsibility is on the seller past the manufacturer's limited warranty. If it wasn't purchased directly from Apple, they could disavow any responsibility if they chose.

Apple Products and Consumer Laws in the United Kingdom

Any defect or non-conformity of goods with the contract which becomes apparent within 6 months of delivery are presumed to have existed at the time of delivery. After the expiry of this 6 month period, the burden to prove that the defect or non-conformity of goods with the contract existed on delivery generally shifts to the consumer.

May 31, 2018 1:35 PM in response to l008com

I'm currently dealing with this right now as well. I'm repairing a mid-2009 MBP that's never been updated. The girl said it wouldn't start up and would just show a blinking folder with a question mark. Eventually I removed the hard-drive and plugged it into my desktop and was able to run first aid. I've only gotten the original MBP to read the disk once, but a snow leopard install failed and it hasn't read it again since. It's still pulling up just fine on my desktop. It's a real pain in the ***. The only upside is how easy it is to replace these cables.

l008com Author

Level 1

101 points

Sep 11, 2017 11:02 PM in response to l008com

Just replaced another one of these cables tonight. Still no known way to definitively diagnose them, which seems crazy.

jhannad

Level 1

4 points

Oct 9, 2017 2:14 PM in response to l008com

So glad I came across this, as it is what is happening to my MBP. 'Genius' bar wasn't much help. Neither were the local mac dealers.

Thanks for possible solution and link to part purchase.

Jan 18, 2018 8:41 PM in response to y_p_w

Oh yes silly me !!

All the following generations of MPB have widely upgraded to flash storages.

Csound1

Level 9

60,063 points

Jan 24, 2018 7:34 AM in response to djk0402

What is the Mac you have, a Mac Pro or a MacBook Pro?

yytab999

Level 1

14 points

Jan 24, 2018 8:08 AM in response to Csound1

MacBook Pro 13' early 2011 Model: A1278

Mar 11, 2018 10:08 AM in response to y_p_w

Have you looked that those SATA contacts before blurting out that comment?

They are all flat wiping contacts, not like the real "Pins" used on old SCSI or IDE cables, which were easy to bend over.

Apr 17, 2018 5:20 AM in response to RMFT76

What did you have to do to convince them this was not just a random problem or User Error?

Jul 23, 2018 2:48 PM in response to l008com

Hi I am facing this problem too. I have a '11 macbook pro 13" and replaced HDD at first (having two of them I did it effortless and moneyless), then without any fix decided to buy another HDD cable and problem seemed to be fixed. I faced the same issue again, still after the same amount of time (avg 3 weeks) so the flat cable failed again. I am currently at the second cable bought and decided to not go for any buy again by now.

At the first fail the cable appeared intact, last time, instead, I felt a smell of hot plastic and observed a polished round area on the tracks leading to the HDD, clue that cable was gone again.

I have no clue about the reason of the failure.

Aug 31, 2017 8:05 AM in response to l008com

Hi,

I'm having the same issue in my wife's MBP, we attend to the Apple Authorized Service Provider, this has been replaced two times, they mention that a batch of HDD flex had this issue and that they will replace it until the issue goes away, but in the meantime now due some random restarts that sometimes happen,

The Hard disk starts to make some noise (this in a period of ~1 year ) is there an official apple recall or a communication from apple side regarding this issue?

Or how can we communicate this to apple and that they take the responsibility of their product, since we bought it the MBP never has been working as should, we have another MBP same year, same day of purchased and works totally different, or better to say: works! is responsive, turn on and off fast, etc.

What do you think we can do in this situation?

Thanks in advance!

Ernesto

Mar 11, 2018 8:51 AM in response to IanD1953

This issue is extremely unlikely to be a connector tolerance problem. As long as the cable is pressed firmly into place, it his self-aligning.

Both sides of the connector are used. The seven pin side of the SATA cable is data. The 15 pin side is power (several different voltages are used in different drives). Notebook drives do not use anything from the 12 Volts pins -- those are used for desktop drive's big spindle motor.

All SATA connectors are designed to be robust enough to be plugged with power on. There are many additional grounds and pins of varying lengths to ensure that when plugging "live", the grounds make contact first, then the power, and last of all the data. MacOS in not able to accommodate "live" plugging with power on, so you should always have your Mac OFF when re-cabling.

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Diagnosing MacBook Pro Hard Drive Cable Failure