Q My employer bought new iMacs with extended wired keyboards. Last night one keyboard stopped working after a 15 minute power outage, and cannot be revived. After Apple’s support reached the same conclusion they are replacing the dead keyboard, but given that it had surge protection, how could that happen?

A A surge protector is not as robust as a full UPS at protecting from spikes in supply. It sounds as if the processor in the keyboard has locked itself up, something that happens very rarely but requires a trip back to Apple to rectify.

Encourage your boss to invest in modest Uninterruptible Power Supplies (UPS) to ensure that problems like this cannot recur – particularly when the warranty has expired.

Comments It is also possible that the keyboard was going to die anyway. Although most electronic products have very low early failure rates, they are still more likely to fail in their first weeks of use than later.

Keyboards may seem pretty dumb, but they still contain microprocessors and are sensitive to power surges and spikes. Although the internal power supply in your Mac tries to regulate the supply delivered to USB ports, a serious spike could still result in a sufficiently large surge over the USB power to upset the keyboard electronics.

Compare the manufacturer’s claimed performance for any ‘surge protector’ with that of a decent UPS, and you will see that the latter should cope far better with disruptions to mains supply. Correctly configured to shut the Mac down in an orderly fashion when the mains supply fails, a UPS also protects all its peripherals better.

Give me a UPS every time.

Updated from the original, which was first published in MacUser volume 30 issue 01, 2014.