I have installed my 808v6 and inserted the C5 cable from the 861v8 into the 808v6 with another C5 cable onwards to my 504 tuner.

When I press the display button neither the 808v6 or the 504 display their firmware no. Every other piece of kit in my system displays firmware correctly.

Before I inserted the 808v6 the 504 displayed firmware without a problem.

In normal operations both 808v6 and 504 respond promptly and both work fine.

Any ideas for what my problem is?

Thanks in advance for all ideas and potential solutions.

Cinema: DSP750 x3, DSP3300 x 4, DSW.2 x 3, Trinnov A32, 271, Oppo 203, Toshiba HD-DVD, SKY Puck, Sony XW7000 PJ, Screen Research AT, Kaleidescape 4K 30TB
Lounge: 861v8, 808v6, UHD722, DSP8000SEPP, DSP7200HCSE, DSP3300, DSW x 2, 504, C15, Sony UBP-X800, SKY Puck
Bedroom: DSP5200SEHC, G65, UHD722, G08, DSW, M6, C15, 210, SKY Puck
Spare: