Howdy all.... :-)

Alphasonik A-255 Stereo Power Amplifier

The schematic on the back of this unit is pretty scratched up but
I can see some of the details:

9 pin square Molex connector:

Pin 1 (A) Gray + speaker
Pin 2 (B) Blue - speaker
Pin 3 (C) ??? + speaker
Pin 4 (D) Green - speaker
Pin 5 "L????? Input" yellow
Pin 6 Has pin present but doesn't seem to be referenced in the
schematic
Pin 7 "?????? Ground" violet
Pin 8 "?????? Input" white
Pin 9 has no pin present

From what I can make out of the schematic, pins 5, 7, 8 appear to
be connected to the speaker output leads of a stereo radio.

The spec label says the unit is rated for 55 watts per channel or
110 bridged.

Questions:

What is pin 6 for?
How does one go about bridging this unit?
What value of fuse is needed?

Any information on the above topic would be much
appreciated.....thanks! :-)