I recently got YST-SW216 sub woofer, i plug in to input source 110v and i got a green indication light, relay is activating but no humming sound, and i plugged in to input to RCA L and checked but still there is no sound, so i opened and checked all componenets visually, i found there is no physical damage to the circuit components and checked voltage across STK 404 PIN no.5 found 14.21V. i stuck there can anyone solve this problem.
i have all types of electronic equipment like soldering iron, multimeter and etc.