fwiw - for my Mackie CR3s: The two big power supply smoothing caps - the 4700uF caps, C76 & C77, were obviously bad as they were bulging. And no surprise given the heat the power supply generates, esp as it's enclosed inside an insulated speaker box. So I replaced those; but that still didn't fix it. I still had bad voltage readings. I then replaced the two regulator zenier diodes, Z3 & Z4. That did the trick and all is currently working fine. I'll probably modify the powered speaker to leave the electronics outside the speaker box so the heat can better dissipate. There are 'proper' fixes out on the internet that involve bypassing the original power supply regulation section with LM-series voltage regulators. Those fixes will significantly reduce the heat produced, which should help with longevity. Also fwiw - on the MUTE issue re the mute pin on the TDA7265: It has been noted that inside that chip the mute function also performs a voltage safety check; so ideally you shouldn't fix the mute issue by...