We have a ?bug? on system? configuration: on digital outputs: 1 - standalone amp 2 - standalone amp 3 - standalone amp 4 - master amp with 3 slave amps Sometimes (1 day - 2 weeks) any of this amps has lost sound. Always others amps, not the same... We have install an UPS on switcher's power input, but situation is not stabilized. What we shall do?