I just picked up an organ for my daughter. When we turn it on it sounds like a speaker is on very loud sound, hard to discribe. It's a Hammond 340107. I know nothing about it, I have no manual, but I am a handy person, can fix anything. Other than the noise it seems to be in really good shape. Got it from a church. It is very dusty inside, planning to carefully blow it out with dry air, low pressure of course. Any help would be great. The Leslie spins and the sound seems to come from it. Thank you.