I have used the Creative Inspire 5.1 5300 surround sound unit with two desktop pc's, one windows 7 with Creative Audigy original version sound card and the second a windows 10 OS and a Creative Audigy FX 5.1 PCIE OEM sound card. The win 7 pc worked fine for years until recently. On connecting the 5300 unit to the win 10 machine with FX5.1 sound card the audio amplitude now seems to vary. I have checked the connections of speakers etc and had a look at the decoder pcb in the bass woofer/audio distribution unit and it visually seems fine. The remote vol/fader desktop unit and cable check out ok. I have looked for a circuit diagram of the 5300 unit to no avail. Since both pc's now exhibit the same fault I conclude there must be a fault with 5300 's decoder. Unfortunately the only test equipment I have is a multimeter. Has anyone any ideas or have had the same problem. Creative say it is too old and to upgrade. Thanking you in anticipation.