Although the device turns on and the sound works, the LEDs may be too dim to see. The issue may be caused by a low battery. If the problem exists after replacing the batteries, the LED may be out completely. Check out our troubleshooting guide under display issues to see if LED replacement is necessary.
The problem could be caused by either the batteries or the speaker itself. If the problem exists after the batteries are replaced, check out our troubleshooting page under speaker issues to see if replacement is necessary.