Hopefully a simple question....

Had a Yelo 800 for about 2 years now and have been more than happy with it. Just recently I have got round to getting 5.1 Surround sound.
All works ok and sounds great, but......

I can't get the settings to stay for the DOWNMIX to OFF so each time it is turned off it reverts back to STEREO output. This means every time it is powered up (just standby) you have to set it back for use with 5.1.
All other settings seem to be kept when powered off, it's just this one.

Lost the manual too

Any help appreciated.
Thanks
Mark