via this auction

Update via Kenny in the comments worth noting: "Beautiful instrument but no where near the first synthesizer. The Trautonium was already in use and for sale long before the Hammond came out. Even the Hohner Multimonica predates the Hammond. One could say that the Hammond design was heavily inspired by these earlier synthesizers. The Hammond is an amazing instrument so there is no need for false information."
This reminded me of the 120 Years of Electronic Music site. It's a great resource for the timeline of electronic instruments.
Listing description:
"In the late 1930's, Hammond engineers went way above and beyond to create the worlds first electronic synthesizer, and built it the Hammond way ~ the best. I could ramble on all day about this device, but you're honestly better to visit this website, they've fully documented their Novachord and it's restoration.
As for my specific instrument, it's among the very earliest built (#105) and features what I believe is a factory blonde cabinet accent, which I've never seen before. I think it's original because it's so expertly installed, and wraps around the back to the amplifier compartment. The material feels like a grained vinyl (leatherette) with a canvas backing? It's been stripped off on the left side, but you get the idea. The cabinet will need refinishing as seen, but is in remarkable shape for it's age.
When I decided to power it up for the first time, I brought up the voltage on a Variac - slowly. I heard a loud popping sound and found a bad 2A3 tube, which I replaced with a good/tested one. Once up to line voltage, I was able to actually hear this thing play! Volume, vibrato, attack, and various variations of all the controls were essentially functional on the upper half of the keyboard. I didn't get a response from the lower half of the keyboard. This tells me that the basic components (pre-amp, amplifiers, speakers and motor were all functioning) There are 160 vacuum tubes to check, and about 1000 capacitors! You'll have a good and worthy project ahead of you. I do have a short video of my experimentation, happy to email or text it to you! The wiring harnesses, speakers, amplifiers, and other components appear to be in very good cosmetic condition!