No sound with Marantz SR5015 to a Sonos 5

The Sonos line in should be connected to line level out jacks on your receiver, not line level inputs. CBL/SAT would be inputs, I’d think, not outputs. You’d want to change those. 

If you posted a picture, or a link to the manual, it would be easier to give you more accurate data. 

Modern receivers no longer support a tape recorder output. You may need to use a Zone2 analog output fed to the SONOS Line-In. This Zone2 output may have a Volume control and you’ll need to work out cooperation between the Zone2 Volume control and the SONOS Volume controls.

And, Zone2 input will need to be set to Phono.

Huh? Oh, that means the output of the Denon to Zone 2 is the Phono input?
 

Interesting. I’ve always avoided zone 2 outputs, not only for that reason, but the fact that (at least in the past) they didn’t handle digital inputs (like optical or HDMI). Always seemed like a cheap out, as it were, to me. 

Update- I am getting sound but it is extremely low compared to other sources. I found in another thread, a suggestion that there would be a line in switch on the turntable. I only found an on/off switch which was set to OFF. I switched it to ON, and the volume was louder but the sound quality was terribly distorted.

If you have the phono connected to the Phono input on the Marantz, you’d want to leave that setting to ‘off’, there is already a pre-amp in the Marantz (hence the phono in) and you’re likely blowing the input out. 

You may need to adjust the line in settings on the Sonos Five, though. See the discussion at the turntable thread.

Zone2 tries to be separate room, with its own input selector, tone, and Volume controls. Accessing these controls can be a pain. And, as you’ve stated, there is not always a DAC available. Some Zone2’s have a power amplifier available, some are strictly line level analog out. A few will have a “party mode” where Zone2 input follows Zone1.

I have already adjusted settings on the FIVE per other discussions. Source leve is set to 10, delay is set to MAX. I just posted a photo to show the “ins” I’m using. Note that directly to the right are the ins for FRONT and I had the same result there.