Take the SACD out of the player.

Assyming you have your DVD player connected to a TV or monitor:
On the remote, press setup.OPen the PIoneer's Initial
Settings menu. Go down to the Options menu. Select SACD
PLayback. Select multichannel. Press setup again to save the settings.

Try playing the SACD again.

If that doesn't work, stop the SACD and
press setup to go back to the INitial Settings menu. Go to the
Speakers menu. Select Audio Output. Select '5,1 channel' Press setup
again to save the settings.


Thanks for the suggestion.... unfortunately I've already got those settings
selected.
I'm becoming ever more convinced that I've got a duff disc or a duff player
here.

Since my original post, I've also tried connecting the SURROUND L/R
channels, on their own, direct into the known working CD inputs of my stereo
hifi amp. Even at full volume, I get onlay a barely audible signal (more
likey the result of cross-talk, i'd imagine).