Craigslist Wurlitzer Omni 6500 ad

"Selling extremely rare vintage Wurlitzer Omni 6500 analog dual professional stage organ. Truly analog oscillators and real analog filters amazing cosmetic condition, very very clean inside and outside, nothing broken or missing or replaced, completely original. The organ was sitting in garage for last at least 10 years or more. I plugged it in, lights on, seems all buttons response, but I cannot get any sound at all, not even hum. I don't know what's going on, must be something easy to fix it, could be some disconnection, have no idea, just let it go as is. I have feeling it needs some pro electrical cleaning, it looks very nice outside, but contacts, connectors etc need some cleaning and must be only a problem. as far as I dig internet owni 6500 was the best stage professional analog organ ever made, beside weight of organ only about 50 lbs Polyphonic section sound very much like Oberheim, very rich sound, Wurlitzer use Moog filters in double synth section!!! You can mix sound and get very fat and warm sound, I saw Omni 6500 in action many years ago and it sounds phenomenal. I'm selling the organ in condition as is, If I can get sound price will be up to $3000, that's what it usually costs-if you like to find it. MAKE ME OFFER!"

Original ad here https://sfbay.craigslist.org/eby/msg/d/vallejo-wurlitzer-omni-6500-analog-dual/7285671500.html

I underlined the sections that I found interesting and I want to know what's the difference between a cleaning and a pro electrical cleaning

Original listing is for $999.