You can't have 4 FBC tuners on your receiver. There aren't FBC PnP tuners availalble for the GB 4K receivers. The FBC tuners are the ones soldered on the motherboard. It is like the Solo 4K in this respect.
Have you tried to unplug the tuner and and re-seat it. Remove power to receiver first.
With regards to the tuner setup, it depends on whether you bought S2X or S2 tuner card. The passage below obviously applies when you card is being detected.
If S2X tuner card:
Option S2X-1 Hardware:
Motorised wire to Tuner I
Nothing to Tuner J
Sky 28.2 wire to Tuner A
Sky 28.2 wire to Tuner B
One wire not used.
Option S2X-1 Software:
Tuner A: Simple, single 28.2
Tuner B: Simple, single 28.2
Tuner C-H: Leave as FBC automatic
Tuner I: Simple, positioner, co-ordinates
Tuner J: Loop through to tuner I
Reason for above are:
C-H will be loop-though anyway, so you will get extra 28.2 functionality as these are part of FBC unit
S2X functionality usable on the sats that have this
J will then use internal loopthrough to I, so you get extra functionality
Option S2X-2 Hardware: (I would not use this option)
Sky 28.2 wire to Tuner A
Sky 28.2 wire to Tuner B
Motorised wire to Tuner I (does not matter if you use J)
Sky 28.2 wire to Tuner J (does not matter if you use I)
Option S2X-2 Software:
Tuner A: Simple, single 28.2
Tuner B: Simple, single 28.2
Tuner C-H: Leave as FBC automatic
Tuner I: Simple, positioner, co-ordinates, (if you have motorised wire in this)
Tuner J: Simple, single 28.2 (if you have 28.2 wire in this)
Reason for option S2X-2 is:
All tuners are independent.
If additional tuner card is not S2X:
Hardware:
Sky 28.2 wire to Tuner A (does not matter if you use B, but alter software section if you do)
Motorised wire to Tuner B (does not matter if you use A, but alter software section if you do)
Sky 28.2 wire to Tuner I
Sky 28.2 wire to Tuner J
Software:
Tuner A: Simple, single 28.2
Tuner B: Simple, positioner, co-ordinates
Tuner C-H: Leave as FBC automatic
Tuner I: Simple, single 28.2
Tuner J: Simple, single 28.2
Reason for above are:
C-H will be loop-though, so you will get extra functionality as these are part of FBC unit
A, I and J will be independent 28.2 phyiscal tuners