Hi friends, I'm going to build a regulated source with lm317, use a power transistor, but I don't have those, I can use the Horizontal of a Old TV? If not then, any of these: ECG2309 D1294 D1651 Oh something similar, the polarity must be NPN These transistors are

Hello friend, it will all depend on which transistor you will substitute for the horizontal one, so that you will use the source and what this transistor is doing on the source you want to assemble. If you share the diagram and the model of the power transistor it would be excellent.