a disturbing shade of green

Apple, ah Apple.  Has there ever been a greater idea than power connectors that hold themselves in place with a magnet?

Well – yes, so letʼs narrow it down – has there ever been a greater idea for power connectors (for semiportable appliances) than ones which hold themselves in place with magnets?  I wonʼt actually limit this to MagSafe because MagSafe is not the original nor the only implementation of the idea.  I will say that on the whole I am greatly appreciative of Appleʼs MagSafe connectors, which are generally safer than those which could more easily pull a laptop off a surface (has happened to me) or which might be a worse trip hazard by remaining in place (have watched it happen to others).  This applies to older Apple connectors and to other brands, to other devices than computers, and to non-power connectors on computers generally.  (And especially Appleʼs locking LocalTalk connectors, for those old enough to remember them.)

But.

frayed sheath at MagSafe tip

Aside from issues around the actual connector – what is it about MagSafe and Apple laptop cables?  Why do they keep coming apart?  What are these weird sheaths which keep creating problems?

As I write I am taking time out from working out what to do about the latest problem with my MacBook Pro power supply.  To sum up: a few days ago the sheath started wrinkling next to the MagSafe tip.  At some point last night it frayed catastrophically; perhaps instantaneously.

Now I get a chance to look at it, I see the interior of the cable is disturbingly green.  Packed with verdigris, which indicates some movement of copper somewhere out of the actual cable.  But where does the grease come from?

Thereʼs an outside chance that the copper has moved up from the cable end as an outcome of my resoldering efforts last year.  This is the second and fourth MagSafe power supply Iʼve had for this MacBook.  The distinguishing feature is perhaps that itʼs spent more time “on” than previous ones, as the battery no longer holds power too well, so I leave it in place much of the time.  Is it just hotter?

The first PSU had a problem at the other end – the sheath shrank over time and got pulled away from the adaptor, exposing the shielding underneath and allowing it to fray, after about six months.  Seemingly the sheath wasnʼt clamped inside the PSU case.  The second one (supplied under warranty when Iʼd had enough of the first after about two and a half years) had a tactilely different type of sheath.  It appears to have the opposite problem – it expands with time.  The first symptom of which is that it pushed the actual MagSafe tip off the cable after about six months, with about a dayʼs warning in dodgy power status indication.  I had a third – a cheap knock-off as springing for the Apple-made one (now past the original warranty) wasnʼt an option.  It lasted about six months before the tip fell off too.  (So itʼs not just Apple.)  Then back to the second; I fixed it myself (in the process, removing about an extra inch of expanded sheath), and the fix has lasted longer than the original.  Latterly it has been yellowing – probably Boron flame-retardant surfacing as with old ABS cases.  Now this.

frayed sheath at MagSafe tip

And grease?  The question remains.  Even before its initial failure, the cable sheath, which unlike the original PSUʼs sheath felt as if it was well adhered to the cables below, seemed to have begun to separate towards the connector end, presumably with expansion.  When it finally fell off, a crease of sheath was visible.  Could it be that under the influence of heat (voltage drop will do that) something greaselike was being exuded between the outer and inner sheaths?  Weird.  Perhaps not impossible.  Plastics often contain softeners; plastics for flexible applications more so.

I dare say Iʼll need to fix it again, though as it still seems electrically sound Iʼm thinking heat-shrink sheath rather than resoldering.

But Apple, oh Apple.  In 1993 I got a PowerBook 145b.  As a computer it was something of a waste of time when compared to contemporary desktops, and I went back to paper for the intended purpose of minute-taking.  The battery lasted longer than the MacBook Pro batteries, but is no longer usable by itself.  But.  The PSU that came with it still works perfectly well.  Plug it in and all is good.  The connector was not a MagSafe, and it represents a slight trip hazard (though to be honest the PB145b is too heavy for the connector to easily pull off a table before slipping out).  The PSU didn't have the cable-winding hooks which are the major advantage of latter Apple power adapters.  But the cable was always comfortable to hold, and the sheath never went anywhere.  Nearly twenty years later it is as good as new.

frayed sheath at MagSafe tip

What has changed since?  A lot, I know.  But could it be that the product development people under the reviled Scully and Amelio were just allowed to do their jobs that bit more?  As in, making things that were practical rather than chasing experimental diminishing returns?  Perhaps?  Whereas the opposite may have been true of the software people.  Well, itʼs a weak argument, because the whole laptop at the time was only vaguely usable – but wouldnʼt it be nice if the balance at a given manufacturer was such that things worked and kept working, and were designed to deal with failure?

Or as Iʼve said before in other contexts, could we please have a MagSafe cable that plugs into the transformer end as well as into the Mac, so that the inexpensive friable cable can be replaced annually (if need be) without having to shell out for an expensive but otherwise durable PSU?

Either that or my next fix will be to wire my 19-year-old PSU into my four-year old laptop.  Somehow.


Update:  This article has been updated with photographs at 2013-12-08.  A new post on the issue will follow soon.

Update:  The article updating this one is here.