As someone else said, instrumentation scopes include a front panel Cal
test point. This is a source of a known voltage and frequency square
wave train, which can be used to the input of each vertical channel to
test calibration. If it is as marked on the Cal point, the vertical
channel is OK for amplitude. Look at the squareness of the wave for
If the trigger and timebase are working correctly, you can rotate the
time per div. knob and trigger knobs an stop the procession of the
square wave across the screen. It should hold steady if you use DC
Other ways are to take a battery powered signal oscillator along for a
Rotate the brightness control and see if you can dim the trace
completely, and turn it up far enough to be good in sunlight.
Same for focus, rotate it over its range and make sure a sharp trace is
found at one setting.
Best of all take a technician along with you, who works with scopes in
Tektronix and Philips both had booklets and now maybe we sites on how to
use a scope. John Lenk and others wrote troubleshooting books.
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