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Does anyone know what type/specification of coaxial cable is used from the transformer brick to the MagSafe connector in the A1343 power supply?

The cable from my 85W MagSafe power adapter to my MBP (the cable from the transformer brick to the MagSafe connector) has been chewed pretty badly by my cat, and is now unusable. The break is near exact center on the length of the cable. I've found a fair amount of information out there that I can repair the cable by soldering the center conductor and braided outer conductor back together, but I'm wondering whether I could source a proper coaxial cable splice kit for it.

Here's what I've determined so far, from cutting apart my damaged cable:

  • outer jacket diameter appears to be 0.130 inches, +/- 0.005 in.
  • next layer is a shield conductor, OD ~ 0.085" +/- 0.005", which appears to be made up of two layers of silver-colored fine metal wire (feels like silver-plated copper but can't tell for sure). These are NOT woven like larger coax, but rather are two layers in a spiral-wrap around the dielectric insulator, wrapped in opposite directions.
  • dielectric insulator is .070" +/- 0.003", white in color, unknown material but feels like PTFE.
  • Center conductor is fine stranded (strand count appears to be 50-100 as a guess), same material as the shielding. Looking at the cross-section of the center conductor gives a distinct appearance of copper color, strengthening my feeling that this is silver-plated copper. Diameter appears to be .045" (1.143 mm, or about 17 AWG) but I can't be positive as the thin strands won't maintain form in a caliper.
  • Most independent information I've seen mentions a fabric or other type of "string" somewhere in the shielding (presumably for end-to-end strain relief), but I wasn't able to locate it.

I can't seem to find any source for this, or even specs for it. Still, it seems strange to me that Apple would manufacture a custom cable gemometry just for these power adapters?

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Apple may well have chosen a custom cable geometry to handle MagSafe's combination of high current / multiple polarity (i.e. reversible connector) and (I'd guess) some kind of data exchange / telemetry between the xformer brick and the laptop. –  gosmond Feb 24 '13 at 20:41
    
Hmm - a company that invests millions of dollars on packaging technology (the boxes it ships Mac / iPod / iPad / etc…) will clearly not shy away from designing their own custom cords and connectors. Have you ruled out buying a failed device with light wear or are you really most interested in finding new cable of similar specifications? –  bmike Feb 24 '13 at 21:21
    
+1 for "my cat ate my cable" –  Chris W. Rea Feb 28 '13 at 20:39
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1 Answer 1

Apple's Magsafe technology is patent-protected, and there's a good chance they used a custom-manufactured cable to make it even more difficult for 3rd parties to sell cheap relacements.

Ifixit has a page describing How to Repair a MagSafe connector which may be of use to you. Excellent close-up photos & detailed instructions.

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