Vintage Synth Repair

Hi new to the group hope someone can help me. I have been given a T400 which
was fully working when picked up I have cleaned all the dust and cobwebs
from the inside and polished up the keys and cabinet before placing in the
house. For some reason i carnt get a sound out of it now. I switch it on  it
lights up generator turns leslie motor runs fast and slow the rythme box
light flashes to the beat but not a sound from anything swell pedel moves ok
any idea`s? ( did move out the pedels to fix a spring that had come loose)
Regards Roy(UK)