Zend certified PHP/Magento developer

ISY IKE-5000 keyboard only lighting up when connecting to a USB charger port

Whenever i connect my ISY IKE-5000 keyboard to ANY computer with USB 2.0 or 3.1 ports, the keystrokes work correcly but i can barely see the keys as there are no lights, when there should be. I have used two Windows computers, one Debian computer, and the USB charger i have connected to the mains.

Testing with a USB charger connected to the mains reveals that it does light up whilst connected for a few seconds before turning off.

How can i fix this without replacing the keyboard?