I have a Yamaha amp I think early 70's and it

I have a Yamaha amp I think early 70's and it looks to be a organ amp at that.I cannot find any model numbers on it just a Yamaha badge.It has 3 rotating tremelo speakers and 4 normal speakers.It has 3 curcuit boards with power supplies on each one the first one has 240v into it and the other two are powered off the first.The only numbers I have are on these boards which are p/n ND90065 and s/n 480 40491 on the first board and p/n ND90085 x 2 and s/ns 480 40507 , 480 40512.The actual circuit board has a p/n LC-1136.If you know what model or have any diagrams I would really be grateful.