USB connector faults on logic board?

in Genius Bar edited January 2014

I was having problems with reading and writing data to a USB drive. It would erratically produce the spinning beach balls and once in while I would get a "cannot read (or write) to drive" or something like that.


I bought a copy of Scannerz to test it figuring the drive would be bad. I got Scannerz because it wasn't expensive - no other reason. In any case, I started testing the drive and sure enough Scannerz identified errors and irregularities, but with one catch: they weren't repeatable. Their little troubleshooting guide states that if you get non-repeatable errors, it's likely the system or another component causing the problem, so I followed some of the procedures to isolate it.


First, I assumed surely the drive was the problem so I put another, old but decent USB drive on, and it too showed the exact same, erratic problems. I concluded that obviously the cable was bad. I took the USB drive and the cable and attached them to an old iBook, and both ran flawlessly. I put the USB drive and cable on all the other USB ports (this is an iMac with 3 USB's on it) and it ran fine on the other ports. Finally I called Scannerz tech support and they told me the most likely culprit was that the connectors on the logic board connecting to the USB port were probably cracked and making intermittent contact. They said this problem was fairly common if the there's something plugged into the logic board and when it gets subjected to an impact, it almost acts like a lever and causes the logic board traces to crack or separate. I asked them if I could fix this and they essentially said "No, you just shouldn't use the port anymore."


Here are my questions:


1. How common is this problem?

2. Can't I fix it by opening the unit up and re-solderling the USB connections on the logic board back to the USB port? Seriously, how hard can that really be to do?


Thanks in advance.


PS: By the way, this is my first post here. It's a very nice looking site. If this post is in the wrong area, please move it to the right one. Thanks again.


  • Reply 1 of 2

    This probably should have been posted under one of the "Genius Bar" sections of this site.


    LOL! An ohm meter built into the Mac! :-)


    Scannerz is fault detection software. It's real purpose is to test and detect faults of any sort associated with the CPU, I/O controller, peripheral interfaces, and hard drive. It does this by doing what amounts to surface and seek scans on the drive and using the progress of the scan as a "marker." If a scan detects repeatable problems, the drive has surface scan problems, probably from a head crash. If the results aren't repeatable with respect to the scan progress, it indicates the problem is usually elsewhere in the system - like it was in your case. 


    The way it detects errors in cables is NOT by performing resistance tests. Scannerz monitors system timing. When a cable has an intermittent break in it, it will be making contact one second and then making no contact another. When data is passed along the cable and a break like this is encountered, the system will go into a series of re-tries passing data on the data line. If the line is completely broken the operation fails and typically an I/O error is generated. If the operation succeeds after numerous retries the operation succeeds but Scannerz marks it as an oddity because the amount of time to do the operation took too long. If you get lots and lots of unrepeatable oddities during a test, you can just about count on it being a cable problem. They used to have some good videos on their site illustrating some of this but they seem to have taken them down and put up videos that seem more basic, with one being almost instructional.


    There seem to be a fair number of write ups and posts on it on I've noticed the product seems to be popular in Europe but hardly heard of here in the U.S., which is odd  because the company is an American company.


    Regarding your USB port, how rare is it? Well, if you put something into the USB port and then whack it, I don't know why anyone wouldn't be surprised if it broke. No offense guy, but what your asking is kind of like this: "If you're driving a car and you veer off the road and hit a telephone pole, what are the odds that your car's going to be damaged?" Physical damage is physical damage.


    Can you solder it? Well, do you have a soldering iron with a tip about the same shape and size as a needle? If you do, or you have logic board re-flow equipment, then sure, you can fix it! If you don't have logic board reflow equipment or some of the soldering iron's capable of doing that  (they typically cost MORE than logic boards, by the way) then no you can't. Connectors aren't what they used to be. The connectors on all logic boards nowadays are tiny and fragile, and they can crack or break very easily. There's very little you can do with a logic board ... a few things, but not many.


    I'm sure that some "hardware hackers" will eventually chime in with tricks about using a heat gun to reflow it or saturating a solder wick with hot solder and using some trick to reflow it, but IMHO most of this is more likely to risk damage to a system with are really, really, minor problem.


    Look at it this way: Go buy yourself a USB hub. They're selling for what? About $5-$15 for units with 4 or 5 ports. Plug that into one of the good ports and VOILA, you now have more ports than you had before AND you didn't destroy your logic board trying to fix a trivial problem.


    A word of advice though - don't hit the port again.

  • Reply 2 of 2

    Thank you for your informative answer about how it detects cable problems.


    My other question was how common this is on USB ports. To the best of my knowledge none of the USB ports have ever been subjected to impact, but then again I'm not around the system 24 hours a day either. I know a little bit of electronics because I was into it as a kid. I would think Apple would reinforce I/O ports or take some steps to make them not-so-hard to break. In any case the USB hub is a good idea too.


    Next time I'll post this in the "Genius bar" section but this was my first post here anyway.


    Live and learn.



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