Just to mention: I have the original hd plugged in.. and still the same result as you !
Mine is a version 1.6 ! So i have the 5v connection and also i have installed the rebuild LPC.... everything looks fine !
How i did it:
Pin header install - the 3 LED wires - The rebuild LPC - The 5v connection
Then i plugged all cables back in (and the chip of course
And when i turn it on, it turns on and off 2 times then the 3rd time i keeps being turned on but no video output !
This really sucks !