
Here's the scoop.  When you get your home brew receiver working, would
you be willing to share it with the rest of us?  I always wanted to
build my own but never have the time to fool around and design it.

pin 1:  signal ground
pin 2:  signal
pin 3:  always hot +6 volts
pin 4:  +6 volts, hot only when preamp is turned on
pin 5:  infrared repeater connectors

The infrared repeater jacks on the back of the preamp are not connected
to anything inside the preamp except the 5 pin connector pin #5.  There
is a 150 ohm resistor between the two jacks, with a 1.5K from pin 5 to
ground.

The signal pin #2 in the preamp is summed with the built in IR receiver.
They use a chip called CX20106A and a BJT to amplify the signal.  I would
imagine the logical way would be to duplicate this circuit and use
it as the external receiver.

If you need more info, let me know.