Yamaha Moxf8 has volume drop out

My Moxf8 recently started dropping the volume to almost nothing. If I cycle the power, I comes back to proper volume then drops off within seconds. If I change the program, it goes to proper volume but then drops off. I have the audio out connected to a pair of powered speakers and headphones. The USB is connected to my desktop computer running windows 10 pro. The volume through USB an into Cubase seems good..
Please advise

It could be a dirty encoder. is it a layer volume or overall volume that drops?

Thank you for your reply. What do you mean by “layer volume”? After power cycle or program change, the volume is good then it drops off after about 20 seconds. Even after pushing the volume slider all the way up, I can barely hear it. Does this help?

I looked into it a little more, sometimes the assignable controls can control the volume of a layer/voice. In your case it is most likely a dirty master volume fader. first try some compressed air and if the problem persists try Deoxit F5. have you noticed if the volume changes erratically if you move the fader or touch the panel around it?