I had a 921 whose HD died. I swapped it out for a new/refurb 921 from E* but it wouldn't boot up. After a service call it was determined it was DOA. The second unit is now doing the same thing. It blinks continuously but won't reset upon unplugging or holding on power switch. It worked briefly then this. No menus are accessable since it was first fired up. I have unplugged everything, left it on, replugged, run sat feeds through a surge protector, fed vid signal directly from unit to tv (instead of through avr) turned on/off etc. Other sat units in house work fine (508 and 4900). Ideas?