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1st gen MacBook Air.. I replaced the failing internal HD with an 3rd party SSD (wasn't hard, but replacing the fan which was also broken was much trickier - pro tip: don't try using a 00 screwdriver on 000 screws). [will update this question with SSD make+model asap]

Problem: SSD visible on boot only sometimes, and oddly enough, only when the Mac is cold from being carried around outside (where its below 0 C right now). Also, when the Mac is initially cold enough to make SSD visible, it is usable, and can even booted from, even as the Mac is subjected to higher temperatures, until shutdown or sleep.

A little more history: When first connecting drive, didn't seem to work, but after several disconnections & reconnections during process of replacing the fan (took a few tries since at first I first didn't have correct screwdriver, see pro tip above), SSD suddenly appeared on boot. I used it for about a day, after which I had to disconnect & reconnect again (to finish installing fan since I finally got the correct screwdriver) which made it disappear again. I tried reseating connections several times, then finally gave up for the time being & closed up the case, resigned to use my external HD exclusively. Only a few weeks later did the temperature outside drop allowing me to notice its temperature-dependant, semi-working state.

Question: has anyone ever seen such behaviour? Is it likely to really just be a matter of reopening case and reseating connections even though my repeated attempts at this have failed? (doing it wrong maybe?) Or might there be something trickier I should try?

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It would be fascinating to know the temperature above which it will fail to boot. It might narrow down the component that is failing... –  bmike Feb 25 '12 at 22:55
    
I doubt the temp is playing any role. SSDs work up to quite high temps and they don't generate much heat either. Also if you are talking about booting I would guess the computer isn't working too hard. –  latusaki May 2 '12 at 1:53
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1 Answer

up vote 1 down vote accepted

If the original drive works inside the MacBook in any temp, then id say faulty SSD.

If not, then faulty MacBook :(

temperature based faults are usually categorised as things like dry joints, where solder between two surfaces is not correctly made and the contraction due to cold brings the surfaces in touch and heat creates expansion breaking the connection.

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That could fit with many connects/disconnects but isn't too far stretched ? –  latusaki May 2 '12 at 1:54
    
From a physical electronics standpoint, it's not a stretch by any means. Improvements in manufacturing processes have increased the reliability of products however no process is 100% reliable. I worked in a high volume manufacturing facility in the late 90's maunufacturing safety critical components for cars (crash bag controllers), and failure rates were about 3%. We ran every item through hot/cold chambers running batteries of functional tests. I very much doubt that SSD's are put through any such rigor so I'll stick with my answer as Occam's Razor says it the simplest and most obvious. –  Stu Wilson May 2 '12 at 8:05
    
To follow up.. I recently acquired a different brand SSD, and all works fine. I also got an external case, and the previous SSD worked in that too! I suspect something about the ZIF connector to the SSD, as the one from the external case looked to go in farther than my MBA's connector. Could some mysterious temperature based fault only expose itself when the connection is not solid? Could the connection normally be slightly misaligned but contraction just barely get it to work? Don't know, but don't care much at this point, I'm just glad my Mac is working & the older SSD is of some usefulness. –  smallduck Oct 5 '12 at 3:14
    
@smallduck did you put any drive back into the original location or is that now empty? your comment is a little hazy on that point. –  Stu Wilson Oct 10 '12 at 12:16
    
Sorry, by "all works fine" in my comment above, I meant that this new SSD is installed into my MacBook Air that was having the problem and it's working 100%. FYI, the old drive that didn't work in my MacBook Air (but ok in my usb2 external case) is a KingSpec KSD-ZF18.1-128MJ, the new one that does work in my Mac is a SuperTalent FZM28GW18P. Both are 128G drives. –  smallduck Oct 10 '12 at 19:01
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