Stone-Platt Crawley Ltd in Crawley, England manufactured the Diotran voltage regulator module. At one point, they had 30,000 employees but they went bankrupt in 1982. The schematic shown in the Dunlite documentation is a simplified version used to explain how it works. The module is potted and I havenít found a solvent that will dissolve the potting compound and I havenít tried heat yet. (I donít have a bad one that I can sacrifice.) If you have a full schematic for the Diotran regulator, or a tested method of removing the potting compound, I would appreciate hearing from you.