。
She asked him to adjust the TV.
Literal
She [topic-は] TV [genitive-の] adjustment [object-を] him [to-に] asked.
頼む ('to ask, request') marks the person asked with に — the addressee particle for verbs of communication and giving. The thing being requested is here a noun phrase (テレビの調節, 'TV adjustment') marked with を; this is the noun-shaped version of the more common ~てくれと頼む ('ask someone to do X') verbal frame. 調節 (chōsetsu, 'adjustment / regulation') is a Sino-Japanese compound — slightly formal compared to alternatives like 調整 ('arrangement, tuning') or simpler verb phrases like 直してもらう ('have it fixed').