iMac not communicating with USB keyboard

[jjb1989]

Hi all,

I have an issue with an iMac 27". It has a Mac aluminium keyboard connected to it via USB. There are occasions where the keyboard just doesn't communicate with the Mac or has no power. The only solution I have right now is to restart the Mac, but the keyboard is still not always detected and communicating with the Mac after various restart attempts. I have also tried the following:

1) Different USB ports on the Mac, no difference.

2) Tried another keyboard of the same type, no difference.

3) Tried the original problematic keyboard on another iMac, it works perfectly!

I keep thinking the USB ports on the problematic iMac are the culprits but it works fine with other USB devices like the Apple mouse. I can only think the OS is somehow tripping. It is a Mac OS X Mountain Lion. the iMac was provided to us only some months ago so it's practically new.

Any help from anyone who's had these mysterious occurrences? Thanks!

 

[Macman45]

Sounds like a trip to Apple might be the way to go..phone their tech support first and see what they say, but you may have a PSU or USB port problem.

 

[maflynn]

Given the process to isolate the issue, I'd say its the iMac and unfortunately it sounds like a hardware failure.

Do you have any other USB devices that are failing to work when connected to the iMac?

 

[jjb1989]

Given the process to isolate the issue, I'd say its the iMac and unfortunately it sounds like a hardware failure.

Do you have any other USB devices that are failing to work when connected to the iMac?

Hi maflynn,

No none at all. Mouse, superdrive, and other USB peripherals work no problem.

 

[BrianBaughn]

Try an SMC Reset.

 

[maflynn]

Hi maflynn,

No none at all. Mouse, superdrive, and other USB peripherals work no problem.

Odd, since different keyboards fail on the iMac but not another Mac. Other devices seem to work. If the SMC reset fails, its best to bring it in to apple for them to have a look

 

[Fishrrman]

Does the keyboard have a removable connecting cable, or is it fixed?

If it is removable, try a different connecting cable.

If it is fixed -- sounds like it might be an "imperfect connection" between the cable plug and the iMac port.

Do you by chance have a different USB keyboard you could try with the iMac?