cloverleigh,

Alternating while booting up is normal, however, during regular operations, it is not normal for it to flash back and forth. There isn't a way to adjust this, and alternating in regular operation is a sign that the unit needs to be serviced.

I might suggest filling out a service transaction for your product, or contacting service. Unfortunately, I don't know of any other way to fix the issue:

http://www.samsung.com/us/support/online/supportOnlineServiceRequest.do

--HDTech