My Cactus transmitter/receiver combo plus extra receiver arrived today. I can't get the LED on any of the three units to light up. I've replaced the AAAs in the receiver and tried both receivers. The instructions don't even make it clear which position is on for the receiver (red showing or red hidden on the slider). And I can't get the LED to light up at all on the transmitter. I guess before I assume they're defective, I have a couple questions.
1) Will the LED on the receiver light up if it doesn't detect the transmitter, or should it light up when its on, no matter what?
2) What position IS on on the receiver? Red showing, or red covered by the slider?
3) Is there any trick to turning the transmitter on? Do you hold the test button down? Will the transmitter power on when its off the hotshoe or not?

