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Level 1

88 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

Best reply

wiseacre33

Level 1

14 points

Posted on Nov 3, 2017 10:44 PM

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.

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62 replies

yytab999

Level 1

14 points

Jan 25, 2018 6:57 AM in response to Grant Bennet-Alder

Thank you Grant Bennet-Alder.

The current cable (newly installed last weekend) has a newer part number (821-1480-A) than the old one (821-1226-A). The old one worked well for High Sierra for a few weeks. I reordered a 821-1226-A cable which will be delivered soon.

By the way, I reversely format a SDD drive from APFS to HFS+ and clean installed MacOS Sierra (10.12.6). The result is the same - booting fine as external drive but not as in internal drive. Only the drive with MacOS X works.

valenja

Level 1

4 points

Jan 27, 2018 6:09 PM in response to l008com

Hey guys, first post on the forum :-D

Macbook Pro 13" Mid 2012, Serial # C02HP8YRDTY4

Since 2013 I've been going back and forth to Apple about this issue. HDD cable has been replaced now 7 times, most recently 2 weeks ago (Apple was awesome enough to issue a one time out-of-warranty repair). I was using my macbook pro as a desktop for 2 years, and finally decided this year decide wasn't fair. But long behold, the same repair was done, HDD cable was replaced. I know this repair will work for at least 2-3 months. I'm very grateful to this thread for shedding light on this design defect. Aside from this defect, I would not trade my macbook pro 2012 for any newer model. With Mac OS High Sierra my computer is still running smooth and quick.

I'm interested in learning if the "red tape fix" has this any long term effects?

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.

Jan 27, 2018 6:55 PM in response to valenja

valenja wrote:

I would not trade my macbook pro 2012 for any newer model. With Mac OS High Sierra my computer is still running smooth and quick.

I'm interested in learning if the "red tape fix" has this any long term effects?

Yes the long term effect should be the cable is not susceptible to abrasion.

I have a 2012 and I have had no issue with the SATA cable to this day.

(MacBook Pro (15-inch Mid 2012), macOS (10.13.2), i7 480GB SSD 16GB RAM)

I can add—Internal SATA cable are actually not cables but flexible circuit boards, typically mylar, with printed circuit traces taking the place of wires. This type of cable can experience cracks in traces due to aging, heat, vibration, impact and abrasion. They can be damaged quite easily if the unit is mishandled during assembly or re-assembly.

In the case of an intermittent generic failure, the electrical continuity of a cracked trace on both sides of the crack is very often a function of the temperature of the unit at the point where the crack exists. As a unit heats up, it expands, and as it expands, the crack widens, eventually forcing a complete electrical separation to exist on both sides of the crack, hence a failure. As it cools down, electrical contact may once again be restored.

If the HDD/SSD is removable it has always been the go to way to diagnose by putting the drive in an external enclosure bypassing the internal SATA cable. Nothing new here.

One of many reasons Apple went to the PCI-e and soldered storage.

Feb 26, 2018 1:17 AM in response to ludofrombangkok

Hello.

Original disk is only SATAI/SATAII.

Controller on board supports also SATAIII

If you put inside new SSD disk in order to get better performance, or solve bad drive issue, it can lead to worse situation. Because new drive will negotiate SATAIII with controller, and this higher communication speed od SATA bus and on bad flex cable cause this situation. It looks like bad new SSD drive, but isn't. It's still only bad flex cable problem.

JohnyFdz

Level 1

8 points

Mar 10, 2018 2:18 AM in response to l008com

I have a question, it's kind of weird and basically the same issue. I own a Macbook Pro '13 mid. 2012 A1278, I repleaced the SATA cable a few months ago (the original cable failed), and today I'm trying to install an SSD; everything works flawless when I start the computer with an external SATA adaptor to USB, but when I put the SSD in the internal SATA, it just doesn't work, but with the native HDD it does work. What do you guys recommend, should I change the SATA cable again? Same model (821-1780a), or an upgraded model (821-2049)?

IanD1953

Level 1

42 points

Mar 10, 2018 2:32 AM in response to JohnyFdz

I have replaced several of these cables and they all broke at right angle bend just near the two screws that clamp the cable to the case. If the cable is working with the HDD then it is unlikely to be a cable fault. However, I have found that some new cable only last a short time and they can intermittently reconnect.

It would be interesting know what happens if you reboot while holding option (alt) down. If the SSD is connected properly it should appear as a bootable drives.

JohnyFdz

Level 1

8 points

Mar 10, 2018 9:48 AM in response to IanD1953

I have tried also that, when I connect the HDD via internal, and the SSD via external, those bootable drives do appears, both of them, I can start the computer from any of the disks; but when I connect the SSD via internal, and the HDD via external, it only recognizes the external HDD, I can only start the computer from the external HDD (so annoying).

That's why I say it's a weird issue. Some people commented to me that it would be a compatibility failure, and that I should use a Hybrid Disk; but I have made sure that the SSD were compatible with my Macbook, both of them are supposed to be SATA III. The SSD is a Kingston Hyperx Savage 960gb, this is what they comment on the support page: "Our SATA III (6Gbit/s) SSDs are tested to be backwards compatible to SATA II (3Gbit/s). They are not designed or tested to be backwards compatible with SATA I ports (1.5Gbit/s). Most systems made before 2008 used SATA I ports. Our SSDs will likely not work in these systems."

IanD1953

Level 1

42 points

Mar 10, 2018 2:44 PM in response to JohnyFdz

The SSD should work in the bay. I put a Crucial (MX200 SSD) 1TByte SSD in mine without any problems. The only thing I can think of is that the connector which plugs into the SSD is not connecting properly. It only takes a small tolerance error to get a bad connection. It would be worth looking at both the SSD and MacBook connectors with a loupe. The connector is divided into two parts (7 pins and 15 pins) and I think only the 7pin part of the connectors is used.

I would also suggest you get a spare cable. Chances are you will need it at some stage. What happens is that the MacBook case flexes slightly and pushes the cable and eventually one of the tracks breaks. I have used both types

821-1480-A

821-2049-A

but I would recommend the 821-2049-A.

BTW I understand that both the HDD and optic drive bays are SATA III. Some people have installed their SSD in place of the optic drive.

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.

y_p_w

Level 6

17,642 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.

y_p_w

Level 6

17,642 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…

IanD1953

Level 1

42 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

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.

RMFT76

Level 1

4 points

Apr 17, 2018 6:12 AM in response to Grant Bennet-Alder

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.

Diagnosing MacBook Pro Hard Drive Cable Failure