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The March 2015 update of Apple's 13" MacBook Pro Retina Display, model A1502, features fifth-generation Intel Core i5 and i7 processors and introduces the Force Touch trackpad.

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Why precisely does the trackpad cable fail?

I hope to find answers to some questions to help illuminate the root cause behind the well known issue regarding the trackpad cable for A1502 2015 Macbook Pro 13”. I also want to explore the difference between the cables sold by 3rd party sellers (which I allege are non-genuine) and the official Apple trackpad cable.

If you search the forums or the Internet for “A1502 trackpad cable” it is abundantly clear that there is an issue pervading Early 2015 Macbook Pro 13” where the keyboard & trackpad is finicky or ceases to work.

The solution is to replace the trackpad cable with Apple part number 821-00184: MacBook Pro 13" Retina (Early 2015) Trackpad Cable.

This was my experience. I bought the part from eBay ($13 AUD). As experienced by some of the reviewers in the above link I also encountered the following issues: (1) there was too much slack in the cable and it was unusually longer than the genuine apple cable that it replaces and (2) the keyboard & trackpad worked fine but there was no haptic feedback.

I really needed the haptic feedback so I bit the bullet and went direct to the Apple store in Sydney. I explained what I had done and they agreed that the trackpad cable is the issue and said that only genuine Apple parts could be purchased via the store (which is probably well known by iFixIt regulars). They replaced the cable and it worked fine. So I bit the bullet and paid for the $15 part and $120 (again AUD) for the few minutes of labour.

This has been racking my brain though. The original cable that failed in my laptop seemed perfectly fine. Here are links for it: http://ks.fastmail.com.au/2015mbp13-trac... . I honestly couldn’t see any wear or tear.

In contrast here is the ebay cable http://ks.fastmail.com.au/2015mbp13-trac....

The geuine replacement cable done by the Apple store did not have a orthogonal fold for the bottom slide-in connector. It appears there was some more slack.

Here are my questions:

Q: is this a software issue or a physical issue with the cable?

One of the reviewers said this about the trackpad cable: If your track pad and keyboard stop working in macos, but still work in other operating systems like Linux, this may fix the issue for you. I was thoroughly confused why my trackpad and keyboard worked when booted into Linux but not Mac os, but I eventually found someone who said to just replace this and it worked! Who knows why.

I had a similar experience. When the keyboard & trackpad became finicky, I noticed that on resuming the laptop from sleep the keyboard would work fine but the gestures or haptic feedback will stop working. Sometimes just a simple reboot of MacOS Mojave (10.14.5) would restore functionality. Only to stop working after the laptop is resumed from sleep again. This happened for awhile until one day both keyboard & mouse ceased to work and I got the insert keyboard & mouse screen: http://ks.fastmail.com.au/2015mbp13-trac....

I then opened the laptop and reseated the cable and everything worked fine again. For awhile, until it died completely and reseating was no longer an effective remedy. I had to resort to external keyboard & mouse until the replacement cable from ebay arrived.

Q: Why does the haptic feedback not work for some of the non-genuine of the cables? Does this affect some or all non-genuine cables?

So my eBay cable was almost fully functional, only haptic feedback didn’t work. This is what prompted me to get a replacement from the Apple store because i actually thought the issue was more than just the cable. Except Apple replaced the cable with a genuine one and everything works fine.

A review from the iFixIt part link above says this: I used this to fix a trackpad and keyboard that would periodically stop working. It seems to have solved the problem. Only thing is now The Haptic feedback on the trackpad is unresponsive. Has anyone had a similar issue? trackpad works like it should there is just no haptic feedback which is disappointing.

So it’s not just my eBay cable but also iFixIt cables. A different user reports the same issue (which I also responded to): Trackpad works but haptic feedback not there.

Q: Based on the previous questions, is the physical cable more than a ribbon cable? Does it have a special chip or some kind of proprietary system? Why is it hard to replicate a genuine cable?

Q: Will this be a never-ending recurring problem?

A reviewer says this: If your keyboard and trackpad stop working on this model, this flex cable is the likely culprit. My first one lasted 2 years, and was replaced under AppleCare. That second one lasted 2 years also. Now I just installed my third flex cable myself, purchased from ifixit. This one was a bit longer than my previous one, so I used a bit of an "S" fold to fit the redundant bit near the lower connector. So far so good!

This is asinine! So two genuine apple cables and a iFixIt one which sounds similar to my ebay cable with regards to the elongated cable with more slack. This reviewer seems to indicate that there were no issues with haptic feedback.

Q: Does Apple acknowledge this as a well known issue of the 2015 Macbook Pro 13”?

It took Apple a very long time to acknowledge the butterfly keyboards were defective by design. Similar with flex gate with the display connectors. It was abundantly clear when I took it to the Apple store for service the repair tech knew the trackpad cable was the culprit (maybe after explaining to her that I replaced it).

Q: Is this a defective design?

This is a well known issue that spontaneously happens to several A1502 Macbook Pro 13” laptops. Is this a design defect or a wear and tear? I did a cursory investigation of 2013-2014 Macbook Pro 13” which are A1502 as well but they didn’t have this issue. It seems that the keyboard and trackpad use separate cables. Also the trackpad cable is underneath the battery (that is, the cable cannot be seen after removing the bottom shell of the mac). I think in 2015 model they piggybacked the keyboard on the trackpad cable and so they must have a new logic board chip that integrates a controller for both. It certainly is much easier to replace the trackpad cable (it took me about 20 minutes total to disassemble, swap trackpad cable, test everything, and reassemble). So that is a plus. But the spontaneous and apparently recurring breakage of the cable is very suspect and I don’t know if this is considered a defect.

I’m really sorry about the length of this post and all the questions. But I also hope that someone experiencing the same issue can find a lot of the surrounding issues with the trackpad cable centralised here. Thank you.

MacBook Pro 13" Retina (Early 2015) Trackpad Cable Image

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MacBook Pro 13" Retina (Early 2015) Trackpad Cable

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A compendium/writeup of the issue: http://a1502-2015-macbook-pro-13-trackpa...

I want to first thank @danj for providing more information about this issue.

I personally feel the problem is widespread and should be acknowledged by Apple with a repair program I’ve decided to keep a bit of an independent compendium describing the issue with links to guides/DIY videos/consumer law information and what not. I have made a submission to https://appleissues.net/ which is a newly form website that helped inform consumers about the FlexGate issue plaguing laptops.

I think problems like these need more publicity as well. DIY is easy but sourcing the right part (as I allude to problems above) is difficult. Apple has genuine parts but hold it captive and depending on how you perceive it they may extort you over service. I paid $15 for the part and $120 for the labour which should've been part of a qualified repair program.

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@softwaredev - You've boiled down the issue to the lack of access to the genuine apple part which is one of the thrusts of the Right to Repair! Movement (Repair.Org)

Take the time to get involved! While you did a yeoman's job documenting the problems here it won't get as far as adding your voice to the cause (as well as anyone else you can involved)!

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@danj I would encourage anyone to join a Right To Repair Movement. I wish there was a local chapter for Australia. I think it is less of a concern here because we feel safe with our consumer law protections. But let's be realistic, as we continue to make technological progress companies will try to gouge you or violate your rights in subtle ways and deceive or mislead not so . savvy consumers compared to people like us that are dedicated to solving real problems rather than leave it to the hands of a company you thought you trusted.

In my mind the right to repair might not be enough. I postulate that one can never own a Tesla car because they're at the mercy of Tesla for replacement parts and software. Food for thought: what if one day they decide to build in a software licensing or obsolescence scheme where you have to pay to unlock your car to turn left after 100km (ok that'd never really happen when it can put someone in danger - but won't cover the entertainment console!).

The modern world scares me.

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1 Answer

Most Helpful Answer

Just like a peeping Tom, there is a limit on what we can see through the window we are looking through into Apples world ;-}

Apple is not very open as they once were. Even the Apple Stores and authorized service centers Apple has are often kept in the dark! While some employees have a brain (and use it) Apple does what it can to dumb down the staff! Hardware expertise is within the service depot which sees the bulk of the repairs. Apple uses buyers to test their stores employees to make sure they don’t disclose anything to the customer here in the states (they can loose their job). Being in Australia gives you a bit more access as I’m sure Apple is not being as aggressive checking on their employees there.

OK, so what I can tell you is this issue is complex! Lithium Ion batteries breath like your lungs expanding and contracting as the battery is charged and discharged and at rest. All of the keyboard and trackpad/touchpad units face the same issue some more so than others.

The older models place the cable underneath and due to this design the battery would press against it like a vise. In your model the cable was placed on top with the idea the compression issue would be less of an issue as there is more free space to the bottom cover.

Now we need to add some grit (sand) into the equation as we all know it finds its way deep into areas which can be an irritant (bathing suit). Here the grit can wear the insulative coating on the ribbon cable and the grit can also be conductive enough to create a short! So over time with the constant cycles of the battery swelling up the cable will get damaged.

But wait! You said the cable going over the top didn’t face this! Well it does! When the battery gets older even it will press on the bottom cover and when the battery cell fails fully to the point of rupture it really gets pressed! But in normal conditions that’s not the issue and looking at your pics your battery is not puffy so we know thats not your issue.

But! expansion is still a factor here! In your case the length of the cable comes into it and how to apply the adhesive points down. The best way to think this is think how a balloon which has writing on it stretches out the letters as you inflate the balloon.

Here we have something that is not very flexible in its length so as the battery swells it can pull on the cable actually disconnecting it from the connectors! So the trick is making sure you mount the cable so there is slack on both sides. To help out place the cable (with the adhesive sections still covered in place) take a strip of tape on both the cable and battery so you can draw an index mark across at the ideal placement of the cable. Now carefully remove the adhesive covers placing the cable down so your index marks line up.

But I did jump over one step here! The folds! You don’t want sharp folds you want a nice radius at each bend. I use a cut piece of coat hanger (smooth and clean) to help me form the bends needed here (I use a BIC pen ink straw for the SATA cables).

OK, so thats what I can tell you on what I see and do. I do use the correct cable per the system. Some sellers cheat! They sell you the 15” cable for the 13” models (overly long) and might ship you the under battery version instead of the over battery version which is different too!

As to why you encountered a problem with haptic feedback. I’ve never encountered that with the cables I use. There is nothing magic here within the cable, it has no hidden chips. But, its wiring could be different depending on the series it was designed to work in. I’ve not made any study of the pinouts so I can’t tell you if that is what you faced here.

The last part of your question is this a design issue. I can tell you there is a slight length difference in the newer version (about 1.5 mm longer) of the cable so Apple did note the expansion factor tended to pull on the connectors.

I can’t blame Apple here as each system’s battery will expand at a different rate depending on how deep the battery was discharged and how much charge it needed as well as its cycle count. They did address the length issue quite quickly so people who hit the problem got the better cable. More often I saw the newer cable was not properly installed and the battery was already at the point of failure. I’ve also seen damaged connectors on the touchpad and the logic board. Often the act of removing the cable can damage it or the logic board connector if you are not careful!

Update (12/09/2019)

@softwaredev - I'm aware on many of these comments. Sadly, some of it is in error. To start with pure Copper is very soft to make it stronger it's often hammered or drawn through dies as in the case of creating wire. Annealing is not really required as it does not get brittle (not drawn enough or alloyed with other metals to make it brittle). The issue with ribbon cables is a bit different!

Try this simple experiment: Take three exact same sheets of paper 2" by 8" Staple the short dimension of all three sheets so the sheets are in book form. Now roll the the sheets starting at the staple end. You'll note what started out as equal sheets are now changing as you roll and the tighter you roll! Now the gap between the sheets grows!

So what you have seen is the diameter of the sheets won't fit the same circumference as the sheet below it.

So why does that have bearing here? Well, the issue is the same when you start bending these ribbon cables unlike here in our experiment the sheets slide across the sheet below it, here the copper center sheet is adhered to the upper and lower insulating sheets, this creates stress when it is bent! So the copper kinks up just like how a copper wire when bent becomes narrower at the point of the bend unlike the wire which is much thinker the thin copper foil fatigues to the point of failure! Thats the killer, bending beyond what the copper foil can handle. That was the point in this paragraph:

“But I did jump over one step here! The folds! You don’t want sharp folds you want a nice radius at each bend. I use a cut piece of coat hanger (smooth and clean) to help me form the bends needed here (I use a BIC pen ink straw for the SATA cables).”

If you read many of the SATA cable issues you’ll see I’ve talked at length as being one of the P1 points! The other is isolating the cable from the rough aluminum uppercase using a strip of electricians tape.

Here the issue is different! the act of compression against grit or stretched pulling the cable out and/or damaging the connectors with the keyboard and trackpad/touchpad cables.

There is no stresses within the copper sheet traces only by our mishandling.

If you take the time to review how a logic board is made in mass production you can see ribbon cables are made in the same way.

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@danj Apologies for the belated response. This is a very interesting post.

I have conferred with a few other expert repairers and there's a common sentiment that this issue has plagued apple before in a previous incarnation of laptops, specifically the 821-1480 & 821-2049 (aka A1258 hard drive cable issue) which Apple has revised the cable four times and had a small window for a repair program. There's a good discussion on this https://boards.rossmanngroup.com/forum/o... .

"The copper traces are cold deformed and stretched making them prone to cracking." and "No it is a metallurgical problem. Copper that is cold deformed has internal stress in it and without annealing it it will in some cases start to crack to relieve (sic) the stresses. Copper/brass are very prone to this problem and it is known. It is also referred to as stress-corrosion, common anywhere where copper is bend without annealing it." [...]

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Thanks for the update. By the way the other thing I wanted to point out (as a continuation of my previous comment until it was robot marked as spam) is there are actually 2 trackpad cables that Apple sell. The first is part number 923-00518 or 821-00184-A. This is the well known culrpit that is prone to failure.

There is a second revision Apple made that is replacing old cables. 923-01376 or 821-00721-A. I'm actually not sure what the changes are to this cable and if it is meant to permanently fix the issue. But I have seen a youtube video actually replace one of these cables as well. So the problem doesn't seem to have a permanent resolution (yet).

It's unclear to me what changes have been made in both. I think Apple stopped putting orthogonal bends in the cable as you suggested is probably the issue.

Source: https://www.reddit.com/r/applehelp/comme...

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@softwaredev - Here's a breakdown on the cables

Early 2015 Retina MacBook Pro 13" Trackpad Flex Cable - Apple P/N's 821-00721 current!, 821-00184.

The 821-00721 is a slightly longer cable.

Early 2015 Retina MacBook Pro 15" Trackpad Flex Cable - Apple P/N's 821-2652

What can be confusing is the difference between the Apple P/N and the makers ID on the cable. 821-xxxxxx is the Apple P/N. It's best to use it not the makers ID.

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Oh interesting.

So do you think by giving it some slack and not having orthogonal bends then it addresses the issue you claim above is the root cause? I last popped the back shell after the Apple store replaced the cable because I had to put the bracket that covers the top connector. I do recall that there was more slack and no orthogonal fold on the bottom connector. So I'm guessing based on what you're saying this will make it easier.

I have also bought a few 821-00721 from random sources to verify the cable. My biggest concern about pulling the cable out again and reinserting it is that it may need a trackpad recalibration and that needs special sauce software by Apple - and probably AST2 so cloud powered and locked down etc.

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@softwaredev - Not sure I follow you here...

Both ends of the cable need two right angle bends, the method on how you achieve the bends IS the issue I was addressing in the update. You also need to properly mount the cable as each side needs enough extra length so as the battery swells the connections are not stressed which I had stressed in the original post.

The person who worked on your system may have been lazy as the bends are needed so the logic board side clears the metal cover plate and both ends need to clear the battery. If you don't bend the cable you run the risk of abrasion at these locations and you add tension on the connector interfaces.

As I stated at the beginning there is more to this! As more than one thing is involved and not doing everything correctly will alter the desired outcome.

Your latest posting also brings another variable! The source of the part! Ribbon cables are easy to emulate as reverse engineering is quite possible. So the maker of the cable may not emulate the cable correctly!

The material choices the construction the thickness of the insulator and copper layers... Which is why you really want to not risk getting poorly made parts. Stick with a reliable source. I don't buy off of Amazon or eBay blindly (rarely at all). Stick with an outfit that's been around awhile and has a good track record and warranty program.

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