So I got the 4-channel powered mixer and hooked it up to the Yamaha speaker tonight via the speaker output on the back of the mixer. I can hear a very slight hum through the speaker so I know it's getting power. If I plug a guitar in I also hear a little crackle as I plug it in. However I get zero sound coming out of the Yamaha speaker from a guitar or through microphones. I've tried all the obvious things (plug into different channels, try different cords, turn all the knobs on the mixer, etc.) but still no sound. Any ideas?
I'll go for the obvious ones... I didn't pay any attention to which mixer you bought so these are generic.
Output turned up on the guitar itself?
Pickup switch in the correct position?
Cable from guitar plugged into the correct port on the mixer (an input)?
Phantom power provided by the mixer and turned on if the guitar needs it? (Rare for guitars, essential for most quality microphones.)
Speaker the correct impedance for the output of the mixer? (Or if there's a setting for 4 or 8 ohm, is it set correctly?)
Slider for the input and the input gain pot set correctly?
Input channel selected to the output of the mixer?
Master output volume slider up on the mixer output?
Mute switch for the mixer output disengaged?
I went to the top Yamaha link above but the photo doesn't zoom well enough to see what's actually on that board for me. And I didn't feel like digging up the manual.
Speaking of that... Have you read the manual?