Technics SA-8500X 4-Channel Quad Reciever

i bought a Technics SA-8500X 4-Channel Quad Reciever built in 1976 it look’s 100%
Mint but can’t get any Sound at all to come out of it. It is there Top of line Reciever. The Meter’s all light up & the Tuning Meter move’s when you get close to a strong Station. The only thing I can tell is the FM
Light don’t light up at all. I got the Original Service Manual. I hate to send it in for Repair the Weight alone is 75 Pound’s it is a Beast.
I moved all Switch’s & NO Sound. Any Ideas before I send it in for Repair!! I live in Minnesota & can’t find anyone wanting to Repair Vintage Reciever’s.