my scanner was not powering on...tried different outlets and no go. so i called canon's CS and the guy said he would send me a new power brick. i was not thrilled at that "fix"...wanted them to send me a new scanner. so i receive the power adapter today and...the scanner's working again. seems like the 8400F has had lots of problems with the original power adapter...so, if you have this scanner and it doesn't work, could be the power adapter.