How the Eico 628 Tube Tester Works (Teardown + Schematic Overview) скачать в хорошем качестве

How the Eico 628 Tube Tester Works (Teardown + Schematic Overview)

Summary: This video disassembles a vintage tube tester and reviews its major internal assemblies. It also explains the schematic and shows how filament voltages and test connections are routed during emission measurements. Why This Matters: Understanding these mechanisms helps when repairing or calibrating legacy test equipment. It also clarifies how older testers handled socket wiring, selector logic, and scroll-based configuration data. Content covered in the video: • Mechanical layout of the scroll system used to select tube configurations. • Power-transformer taps that supply the various filament voltages. • Wafer-switch routing for up and down positions tied to pin assignments. • Use of resistor-color codes to map switch outputs to socket pins. • Line-adjust resistor behavior and its mechanical off position on a ceramic post. • Parallel wiring of all tube sockets as shown on the schematic. • Test-setup examples using specific tube types and notes on unsupported tubes.