Hi Serge,

Depending on how technical you are, you may want to check the following...

There may be a lot of ripple on the voltage rails, causing the unit to become unstable. You would need to put a 'scope on the PSU output to see this. It could be that the PSU is on its way out.

The other thing to try would be to clean and re-seat all the cards - when the unit stops producing sound, put it into standby and using the display button, see if you get version information for all the DSPs (DSP C/D and E/F) - if any are all 0000000 then the DSP card could be making intermittent contact.

Good luck,

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.