If the LEDs are bright, then I'm fairly sure that they're out of standby...

In which case, I would check to see if they can accept a digital signal from elsewhere.
If you have a CD player or something else with a digital output, then connect that to the D1 input on one speaker and see if you get sound. Use a fresh lead (any phono to phono lead will work) - Then do the same to the other speaker.

If that works, then there could either be a cable issue or a problem with the processor.
If it doesn't work, then there's a problem with the speakers.

Let us know how you get on.

Cheers,

Steve

Main: 861v6 (LPS), 808v6, UHD722, DSP8000SE Anniversaries, DSP5200.2HC, DSP7200.2, SW1600, Sky Q, Cambridge Audio BD, Roon, M80
Office: 861v4 (LPS), 818v3, 800v4, HD621, M&K S150P, DSP5500HC, M&K MPS2810 sub x2
Son's system: 861v4, HD621, DSP6000.2, DSP5200HC, DSP33
Spare: MCD, 100 Series, 200 Series, 500 Series, F80s, C15s.