I was taught to stress the first syllable of "television", but some dictionaries stress the syllable before -sion. My other question is "Does stressing VI before -sion exist in AmE?
Merriam-Webster says that putting the primary stress (or accent) on the second-to-last syllable of television is an "especially British" pronunciation.
I'm an American English speaker, and I don't remember ever hearing that pronunciation.
In American English, the pronunciation with primary stress on the first syllable may be analyzed as having tertiary stress on the second-to-last syllable: ˈteleˌvision.