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Repairing a Macbook 4.1 (2008 model), I found something odd - the cables are breaking:

The left side has a break in one cable's shielding (the wifi antenna most likely, as it's connected to a "broadcom" chip.

The right side has a worn shielding on the wire so bad that a wire was showing - Most likely the reason this unit gives ugly yellowish-flickering that only went away by adjusting the laptop screen's angle.

These were both breaking right where the hinge moves, so I was wondering, is this a common problem on all moving-wire electronics? One cable seems to have cloth-type covering over it, and I didn't see any damage to it - what is this covering called, and can I add some to the wearing cable to prevent further damage? Or would a spot of silicone plastic sealant work as well?

Update

At step 30 of iFixit manual he's holding this wire and saying it's microphone wire:

See silver wire

So most likely this isn't the real problem, unless microphone wire is interfering, something's probably breaking elsewhere.

Update: You can remove the small plastic piece with a half-circle hugging the hinge, but that doesn't seem to make much or any difference in my case.

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  • \$\begingroup\$ Interesting question. I too have a laptop from 2008 and the internal wire connections all seem to be fine, even at flex points. Maybe the bent radius is too low and the cable is rubbing against the cloth? \$\endgroup\$
    – AndrejaKo
    Commented Oct 21, 2013 at 13:56
  • \$\begingroup\$ @AndrejaKo What brand of laptop, just curious? It seems this type of laptop has way more build problems than other brands. Also, did you physically open it about 365*4 times at least? It would seem this would be a lot of stress on any system. \$\endgroup\$
    – NoBugs
    Commented Oct 21, 2013 at 14:25
  • \$\begingroup\$ So when you say "ugly yellow-ish flickering" what do you mean, anyway? Every now and then the whites turn into yellows, and other colors similarly look like they've gone through a yellow filter? If so, that would mean the blue channel of the video signal is intermittently shutting off. The problem might be in the screen assembly, not the main computer. \$\endgroup\$
    – Mike DeSimone
    Commented Oct 21, 2013 at 14:46
  • \$\begingroup\$ BTW, Apple is the kind of clever company that would use a microphone wire as a WiFi antenna. \$\endgroup\$
    – Mike DeSimone
    Commented Oct 21, 2013 at 14:47
  • \$\begingroup\$ @NoBugs It's an Acer Aspire 7720G. I actually operate my lid much less, since sometimes it stays on for weeks at a time. It does have many other build quality issues. For example it's body is starting to crack at places that get hot, some button caps had to be re-glued back into their place, GPU died, one hinge is starting to wiggle a bit, plastic holding metal threaded inserts for screws cracked at numerous locations and so on. \$\endgroup\$
    – AndrejaKo
    Commented Oct 21, 2013 at 19:24

2 Answers 2

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These were both breaking right where the hinge moves, so I was wondering, is this a common problem on all moving-wire electronics?

It becomes a problem if it is not handled correctly by the design. Non moving cable parts should be fixated so they don't get worn by vibrations. The wear can occur on the insulation or at the joints, at a connector or PCB. Moving cable parts should be allowed to move freely (within the cables specified allowed bending radius) or be protected by some means. Flexible pcb's, cable carriers, cable chains and reinforced insulation are common techniques.

One cable seems to have cloth-type covering over it, and I didn't see any damage to it - what is this covering called, and can I add some to the wearing cable to prevent further damage?

It is probably braided cable sleeving. Can be made of fiberglass, cloth or even steel. Check for "wraparound" sleeving if you want to add it to cables which aren't possible to detach.

Or would a spot of silicone plastic sealant work as well?

The important part is to understand what is causing the wear (heat, friction etc. ) and what kind of damage that has already occurred. If the insulation is broken on several conductors close to eachother, it is usually a good thing to take the conductors apart and reinsulate them individually.

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Given the tight design specs Apple uses in their MacBooks, adding covering to a wire might not fit, much less fix anything. Replacing the part in question is what I'd recommend. You might want to check out iFixIt.

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  • \$\begingroup\$ What I'm seeing is probably not the root problem - see update above. \$\endgroup\$
    – NoBugs
    Commented Oct 21, 2013 at 13:40
  • \$\begingroup\$ What about covering the slightly exposed wire with plastic goop? \$\endgroup\$
    – NoBugs
    Commented Oct 22, 2013 at 0:43
  • \$\begingroup\$ Again, there's no guarantee that it will cover it completely and fit back in the box. And you need to research the thermal performance of that plastic goop: the bare wire could be caused by an exposure to a heat source, which could just as well melt the goop away too. \$\endgroup\$
    – Mike DeSimone
    Commented Oct 22, 2013 at 4:03
  • \$\begingroup\$ And some goop can absorb moisture, become conductive over time, and cause other problems. \$\endgroup\$
    – John U
    Commented Apr 24, 2014 at 9:11

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