i have a yamaha psr 1100(like oriental)and when i had choosen for example a voice from woodwinds lets say saxofone when i press another family for example synth,the voice change automatic to one of synths..how can i stop it..i want to change the voices manualy and no automatic.i had read 5 times the manual but i can't find it.please help!!!

You'll need to access the sound "group" from the A-J buttons on the left and right of the screen, and NOT the hard wired buttons in the sound groups.
eg:
You have a piano sound in KB1, Strings in KB2, and a bass in LH.
To switch from piano to organ ..... push the button next to the piano (F) and call up the organ group. Push the desired organ when you are ready for the switch. It won;t change automatically when you get the new group, or family of sounds.

Call me if this is unclear: 215-284-1328

haha..yes thats it!! i can't belive it was so easy.i was looking for it for months.thank you very much. and another two questions,can i put more memory in my psr 1100 and how if i can?and can i update my operating system like in korg synths???? my mail is kglykiotis@gmail.com