Hello my name is ***** ***** among others we are an Allen repair center. Some of your questions I can answer and some I do not have enough information on. So lets see how far we can get. Static can be caused by many things but most of them are minor. It can be caused by tarnished connectors, Dirty volume controls, bad computer, Bad transistors, or noisy capacitors. any of which can be caused by age. The first thing you need to do is move the expression pedal and see if you can change the volume of the static. If you can not change the volume that means the trouble is in the amplifier system and probably not expensive. If you can control the volume of the static with the expression control it could possibly be a computer issue. In the Allen organs you do not repair the computer board they are exchanged for a repaired one from Allen. With that age I would look at the foam surround on the speakers they will rot in about 20-25 years that can be repaired for around $60.00 per speaker. If you got it for what you think is a good price, you need to consider the transport charges and because of the problem that is unknown i would try to reduce the price at least a little. At the least buying something with unknown problems is a risk of some kind, But the Allen's have held there value over the years.
I hope this has helped and if you have any additional problems, or would like any additional information or assistance, please do not hesitate to let me know. And if you can take a second to rate my service by clicking one of the stars at the top of the page, then submit, that would be greatly appreciated.
I wanted to check back with you to see if there are any other concerns or questions? If not please rate my answer.