I got interested in analog computers over the summer and ended up buying a Comdyna GP-6 off of eBay. They still make the GP-10 version and the Comdyna finds application in teaching labs and in control systems engineering. You can read about the history of the Comdyna GP-6 here.
The unit works and as a first computation I patched it up to simulate the Lorenz system.
The Lorenz system of ODEs is given by: