I've just had my third case of iC proprietary USB cable failure. The symptom is identical to previous failures: the cable is no longer recognized at all by the iPad and/or iPhone. No cause is apparent.
I've got multiple iC devices here, so you can be assured I've done all the troubleshooting steps to diagnose the cable is indeed not functioning at all.
Given the multiple failures I've experienced, it seems logical to conclude it's not a 'bad cable' problem and is (therefore) somehow related to my gear.
If that is the case, perhaps the following are the potential causes:
1. A problem with the USB output on my iCA4+ which eventually results in cable damage
2. Cooked 'inline dongle' due to being left ON (connected to iPad and iCA4+) for extended periods.
Putting pro audio aside, I've ever had 'standard USB cable' fail in this way.
As far as I know, the only _electrical_ difference between the iC cable and a standard cable is the inline dongle on the iC cable, which is the proprietary circuitry for charging connected devices. The dongle is the part of the cable which gets hot. On that basis, it seems likely the failure lies within the inline dongle.
The problem is determining the cause.
This particular failure occurred in a circumstance which may or may not be related: I updated to iOS10 while the cable was connected to the iPad. The 2GB upgrade had auto-downloaded and was consuming too much space on the iPad so I upgraded. The upgrade went perfectly, except the iC USB cable was now dead. Other iC USB cables work fine with the upgraded iPad - the dead cable is the one that was connected during the upgrade.
As far as I recall, the previous two cable failures I've experienced did not occur during an iOS upgrade. It seems reasonable to suspect the upgrade was just a coincidence, but I guess anything's possible.
After the previous failure, I committed to NOT leaving the device ON with cable connected for extended periods, but over time I became lazy and left everything ON for extended periods because its nice to immediately make music anytime I get the urge. It also means I don't need to worry about the battery charge in my iDevices.
NOTE: all my devices are on high quality APC UPS. I don't think the problem is caused by the AC power. Also note that I've ever had a issue with other pro audio devices which are permanently ON. Among other things, I run a mastering studio which is always ON and has generally been in that state for more than a decade. This is because power is a bit like blood - it's usually better to maintain continuous flow, as most breakages occur as a result of spikes during switching ON or switching OFF.
I'll send all 3 failed cables to iC for determining the failure point and will order yet another replacement.