The X550 MIMO wireless router is one of our best performing products that has received
rave reviews from media and users alike. However, some of these devices were shipped
with faulty power adapters that can result in substandard performance. We would
like to assure you that this defect does not in any way pose any hazard. The defective
power adapters may cause the device to shut down unexpectedly or have a difficulty
in powering up. It also may cause the power (PWR) light to remain solid green while
LAN 1-4 light flash simultaneously even when all ethernet cables are removed from
the LAN port.
The power adapters in question are model number DSA-12W-05 FUS.
The model number may be found by head of X550 adpater. (See below photo)
X550 Power Supply

If you are experiencing any of these difficulties, please completely fill in the
form below and we will immediately ship you a brand new power adapter by priority
mail, at no cost to you whatsoever. ZyXEL promises our customers the highest quality
networking solutions and we make every effort to stand by this promise. Please accept
our sincere apologies for any inconvenience this incident may have caused you.
Sincerely,
ZyXEL Customer Service