Protek Service Manual -

Internal high-voltage capacitors (especially in oscilloscopes) can hold a lethal charge long after power is removed. Static Sensitivity:

The flowchart directs: “If +15V absent, check Q1 pass transistor, U1 (LM317) regulator, and R7 sense resistor.”

Protek is currently a brand under several global distributors (e.g., Protek Test & Measurement in Germany, or the US-based Protek Electronics). Their support sections sometimes host legacy documentation. Email support directly with the model number and request the “service manual, not user guide.”