Yamaha CS80

Hi every one , MR microsine have a parts request . 

4 (IG00157) from the tone selector pcb on panel 2 . 

5 complete pushknobs with preset name ,,,, 
harpsicord 2
panel 1 
panel 2
string 3
string 4 

and finaly the mix fader ( big dual gang ) , the one next to the tone selector . 

when it come to circuit design i am truly retarded .If someone can help me or just lead me .... with what can we replace the IG00157 , the circuit is on page 65 of the old crow cs-80 service manual.
thanks .