A friend had a similar problem with the SC 35, he unplugged everythiing and decided to test it one more time before taking it to the shop. The next day it worked! I don't have an explanation since he swithed amps, cable and swapped speaker inputs the day before.
Klipsch RF 7 based HT 7.4, Pioneer SC 35, Acurus 200 Five, Dayton 18 Ultimxa Dual Sub Cab(2), Dayton 18 Ultimax Large Vented Sub Cab (2), on Berhinger I Nuke DPS amps, Samsung BDP F 7500, Asus/My Book Live HPC 4 TB
Yaquin VK 2100 amp, McIntosh XR 5 speakers, Samsung BDP F 7500