Page 1 of Amstrad Sky Box RF Tuning

I have an Amstrad DRX300 Skybox and want to change the RF output from 69 to another channel. I can get to the menu for RF outputs but when I change the channel output to say 23 and press `select` the TV goes blue screen and a 5 minute countdown begins and then TV turns off. When I turn it back on it has defaulted to RF output 69.


How do I save the new setting??

Help appreciated thanks for any replies.