Have you done a factory reset of the device yet? It would be recommended to do so for any second hand purchase, before attempting to add it to your own system.

Hi, I have tried that but get no response from the speaker. The light either flashes red, or if I add a Sonos bridge, stays solid white. 

From what I’ve read I hold the ‘mute’ button and power up to do the reset. Is there another way to do that?

Many thanks

Iain

According to the LED states FAQ, a solid white light suggests it is connected. I’d double check to be sure it isn’t muted for whatever source you’re trying to play, and if it continues not to work, I would recommend that you submit a system diagnostic , and call Sonos Support to discuss it, or post the diagnostic number here for a Community Moderator to pick up.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution. Given that it is second hand, it is entirely possible someone sold you a bad speaker. 

When you speak directly to the phone folks, there are more options available beyond just the diagnostic analysis.