Just traded for a Sansui AU-G99X this past weekend and I am impressed. I hooked it up to my Ohm Walsh 3XO and it is like I am listening to them for the first time, they are finally getting the power that they need. My issue is that when I hooked it up everything worked fine for a day but when I was listening to an album the next day the left channel went quiet. The issue is only with the phono input, all the other inputs work fine. I switched out the turntable and got the same results with the other table. Toggeling between MM & MC doesn't make a difference. It was on MC (Denon DL-110) when the problem occurred. I'm not sure where to start. I'm not a complete newbie, I fixed up a AU-555a by replacing all the UFO transistors and got it working again, but I'm still a bit lost.. Luckily I've got an external phono preamp to use for now but I'd prefer to use the built in one because it sounded so good. I downloaded the serivce manual but it hasn't been much of a help yet. Thanks in advance for any help!