If you try to play both sides, you'll fail.

Literal

Both-scales [object-を] hang [conditional-と] fail.

両天秤をかける is an idiom meaning 'to play both sides' or 'to hedge your bets' — literally 'to hang a double-beam balance.' The と conditional here states a general truth: 'whenever you do X, Y happens.' A proverbial-feeling sentence.