Hello,
I am sort of stumped trying to fix my Tek 465B scope. It was working fine a few weeks ago but has developed some strange issues as of late.
Symptoms:
1. With no inputs I get flat lines on both inputs. However, when I turn on scale illumination I get noise on both channels.
2. When either input is connected to the calibration output, I see two lines being drawn on the square wave.
I have checked the voltage rails on the power supply board, and the +110, +55, +15, +5, and -8 look to be within expected values and are stable.
Any ideas on what I should check?