Most modern digital oscilloscopes (DSOs) run a self-test on startup; ensure it passes without error codes.
Check for dead pixels on LCDs or "screen burn" on older analog CRT displays. Top Used Models for Hobbyists (2026) Based on current market availability and community favor: buy used oscilloscope
If buying locally, perform these checks to verify functionality: Most modern digital oscilloscopes (DSOs) run a self-test
Buying a used oscilloscope can save you hundreds of dollars, but it requires careful testing to ensure you aren't inheriting someone else's "blown front end" or calibration nightmare. steady square wave.
Connect a probe to every channel and attach it to the built-in probe compensation output (usually a small metal tab on the front). You should see a clean, steady square wave.