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

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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

IanD1953

Level 1

50 points

Mar 11, 2018 3:48 PM in response to Grant Bennet-Alder

I haven’t had a problem with the SATA connectors either but I have had problems with this type of connector in other applications. The problem Johnyfdz is experiencing is unusual so you need to consider the more unlikely possibilities.

I had a close look at my stock of MacBook SATA cables before suggesting the problem could be a tolerance error. It only takes one of the contacts in the cable’s connector to be jamming slightly. In which case a tolerance difference for example between the HDD and SSD PCB thickness could make the difference between on drive working and the other not.

With regard to Johnyfdz problem I had a look back at some of old posts and there was a suggestion that because the link speed of a HDD is slower than a SSD a faulty cable that worked OK with a HDD may not work with a SSD.

In case it helps this is what the system report for my MacBook Pro mid 2012 shows for my SSD’s link speed.

Intel 7 Series Chipset:

Vendor: Intel

Product: 7 Series Chipset

Link Speed: 6 Gigabit

Negotiated Link Speed: 6 Gigabit

Physical Interconnect: SATA

Description: AHCI Version 1.30 Supported

Nov 12, 2017 5:50 AM in response to l008com

Woah! even I am having the same issue. I replaced the cable once, but again the replaced cable too failed. I took it to the Apple store genius bar, and they told me that either the cable has failed, or the logic board. But I can boot by connecting my HDD externally via USB drive. So guess it's the cable again. I have ordered a new cable and will hopefully fix the issue!

I was worried about the failing HDD or the logic board. But the symptoms you have mentioned exactly match mine.

Jan 13, 2018 6:44 AM in response to ludofrombangkok

If the flat wire was faulty again, it would fail on both the original HD and the SSD without discrimination, right ?

Not necessarily. The experience of users here is that the rotating drive can work fine, the SSD can fail miserably, and the fault can still be the cable.

Also, where did you put your felt? At the bend point as the Original Poster proposed, or along the inside of the case, as Brue Computing proposed? or both?

Jan 18, 2018 12:22 AM in response to Grant Bennet-Alder

Hello there,

I eventually decided to replace the ribbon.
After double check, I didn't protect the main "bend" (ribbon attached by the 2 screws going down the bottom of the housing) the first time I replaced the ribbon. So I did it properly with the fresh one. Also used tape on most of its surface.

Still, the 2 previous ribbons didn't have any specific mark of scratch or clear apparent damage...

Anyway, I re-installed the SSD back inside, did a little Time Machine trick and the machine is back super fast as balls.

Thanks every one once again for all the precious help and info.
Hopefully, this ribbon will last longer than the previous one.

Cheers.

yytab999

Level 1

14 points

Jan 27, 2018 6:28 PM in response to valenja

Issue Solved.

The reordered drive cable works fine - the computer resumes normal speed. Clean installation of High Sierra was done smoothly without any issue. High Sierra booting takes less than 20 seconds. It seems the new cable from last weekend replacement is a faulty one - It can handle MacOS X 10.7.6 traffic but can not handle newer OS (10.11.6 to 10.13.2) operations.

y_p_w

Level 6

17,762 points

Mar 11, 2018 11:52 AM in response to Grant Bennet-Alder

Grant Bennet-Alder wrote:

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.

Yeah I've seen them. They're still V-shaped spring contacts (I used "pins" figuratively) inside the female connector that can become bent/shorted sideways if handled improperly. It might be possible to bend them back in place with precision pliers. It's harder to handle improperly with a SATA drive slot like with my 2007 MacBook because the drive slides in/out on rails, but a loose female connector is another matter.

There are military/space grade "Rugged SATA" connectors (Amphenol R-SATA or Nebula) that are designed to be more robust than the standard 2.5 SATA female connector that use bent spring contacts.

http://www.sdksys.com/products/storage-solutions/rugged-ssd-drives/242/1tb-mlc-r ugged-ssd-with-amphenol-r-sata-connector…

http://www.sdksys.com/products/storage-solutions/rugged-ssd-drives/270/1tb-mlc-s sd-with-nebula-rugged-sata-connector-det…

y_p_w

Level 6

17,762 points

Mar 11, 2018 4:57 PM in response to IanD1953

IanD1953 wrote:

I had a close look at my stock of MacBook SATA cables before suggesting the problem could be a tolerance error. It only takes one of the contacts in the cable’s connector to be jamming slightly. In which case a tolerance difference for example between the HDD and SSD PCB thickness could make the difference between on drive working and the other not.

It was pretty clear to me that your claim about a damaged connector was about the "cable" (SATA female receptacle) side and not the drive side. The drive side has the "flat wiping contacts" that Grant was discussing. The connector side has a receptacle with bent spring contacts that can be damaged with improper force. Here's a picture of a SATA receptacle. Obviously it's not the specific MacBook Pro SATA connector, which is custom made for Apple, but Apple's connector has bent spring contacts (that can be damaged) like pretty much every other SATA receptacle.

IanD1953

Level 1

50 points

May 7, 2018 4:48 AM in response to lota68

That’s an interesting comment, which relates to something I have been puzzling over for sometime. I used to find that Microsoft Office applications took a long time to load. Then for an unrelated reason I upgraded the memory from 8 GByte to 16 GByte and much to my surprise I found that Office applications were loading much faster. A few days later the HDD stopped working so I installed a SSD and got as far as loading OSX before it also stopped working. I then realised that the problem was just a faulty cable.

One suggestion I was given at the time was that the cable may have been faulty for sometime and it was causing a high bit error rate and that opening the MacBook’s case may have disturbed the cable. It is only academic but I wonder if anyone else has any other ideas.

leroydouglas

Level 10

199,614 points

May 7, 2018 6:56 AM in response to IanD1953

IanD1953 wrote:

It is only academic but I wonder if anyone else has any other ideas.

Hasn't this thread been beaten to death?

Academic or otherwise—I can say when Apple replaces a HD they always replace the SATA cable at the same time—this should be instructive.

l008com Author

Level 1

101 points

Sep 11, 2017 10:55 PM in response to SergioMX7

If you have a 13", this is the cable you need: MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable (923-0104, 923-0741, 821-1480-A, 821-2049-A) With Bracket / New - iF…

l008com Author

Level 1

101 points

Dec 12, 2017 4:14 PM in response to djk0402

MacBook Pro or Mac Pro?

If MacBook Pro, you can look up the part on ifixit.com, order it, and really install it yourself, it's very easy.

Jan 24, 2018 5:50 PM in response to yytab999

 Menu > about this mac > (system report) > what firmware version is installed?

Sep 10, 2017 9:51 AM in response to l008com

Hello, I have the same problem, my data cable, but I have a question if someone can help me, the part is 821-2049-a in my macbook pro, and I get the cable but the model in this new is 821-0814-a. Is there some difference ? Because my MBP Mid 2012 is working, but sometimes get freeze when I click something or trying to refresh some websites, or opening some programs. Thank you so much!!!

Nov 3, 2017 10:44 PM in response to IanD1953

Thank you for your explanation of the 821-2049-A and 821-1480-A cable differences. I couldn't find that anywhere.

I just inherited a mid-2012 13" A1278 which previous owner said she hardly used in recent years because it got so slow. After resetting the system, wiping the drive and upping the memory from the original base 4gb to 12gb, I noticed a definite improvement. But still really slow and sort of hanging up when installing new OS and other large apps. Even now on MS Office 2016 and Final Draft I get a lot of beachballing. I'm thinking I should try swapping out the Hard Drive Cable and maybe put in a spare SSD I've got lying around while I'm there.

So the cable iFixit sells says it can replace both. But it's pretty costly at $44 (with bracket). I can find some others (with bracket) on Amazon for half of that. But those specifically say they are EITHER for the 821-1480-A cables OR the 821-2049-A cable. Not both. Should I just go with the newer version 821-2049-A?

You also mentioned that Apple modified the HDD mount so it would prevent the case from pressing on the HDD cable. Even tho you said it didn't eradicate the issue, is that something that I can easily accomplish by replacing both brackets?

Any advice would be greatly appreciated.

Thanks.

Nov 30, 2017 7:01 PM in response to l008com

I am helping a friend. She has cancer and doing work for free. She has a 2010 Macbook Pro and the original hard drive failed every test, including putting it a 2nd Macbook pro where I removed the DVD bay in place for a Sata hard drive bay. It failed there too. I purchased a 240GB Samsung SSD, same form factor as original drive. The disk utility (she saved OSX install disk) showed the drive, Smart Status=Ok, everything else looked fine, but when I tried to format said drive I came up with error "POSIX reports the operation couldn't be completed. Cannot allocate memory" Is possible that the SATA cable is bad and it is the root of the error?

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Diagnosing MacBook Pro Hard Drive Cable Failure