Heathkit IO-4550 - Page 37

Page 35
TOUCH-UP ADJUSTMENTS
This section of the Manual deals with the final or touch-up
adjustments that insure the accuracy of your Oscilloscope.
Any time you perform the “Initial Calibration,”’ operate the
Oscilloscope for at least 48 hours, and then perform all of
the following touch-up adjustments. However, any time you
doubt the accuracy of a particular circuit within your
calibrated Oscilloscope, make only the appropriate touch-up
adjustment.
Allow the Oscilloscope to warm up for at least three hours
with the covers on and with the Oscilloscope setting in its
normal operating position. Do not stand it on the rear panel
to make the touch-up adjustments. Keep it in the normal
operating position.
To insure that the adjustments are made under actual
operating conditions, remove the appropriate cover only
long enough to make each adjustment. Replace the cover
immediately after you make each adjustment and allow 5
minutes for the Oscilloscope to stabilize. Then recheck the
adjustment.
If you have replaced a component or serviced the
Oscilloscope, you must perform the “Initial Calibration”
before you make touch-up adjustments.
Touch-Up Sweep Adjustment (time base calibration) —
Carefully perform the “Sweep” calibration steps (1-19)
starting on Page 28. NOTE: The sweep calibration is
affected when the voltage and horizontal amplifier are
readjusted.
Touch-Up Vertical Amplifier Gain Adjustment — Carefully
perform the “Vertical Amplifier” calibration steps (1-3) on
Page 28. NOTE: The vertical calibration is affected when the
voltage is readjusted.
Touch-Up Trigger Adjustment — Carefully perform the
“Trigger” calibration steps (1-7) on Page 27. This
adjustment is not affected by other adjustments.
Touch-Up X-Y Adjustment — Carefully perform the “X-Y"
calibration steps (1-8) on Page 30. NOTE: The X-Y
calibration is affected when the Y1 vertical amplifier,
horizontal gain, or voltage are readjusted.
Touch-Up Sweep Length Adjustment — The SWEEP
LENGTH control (R437, on the time base circuit board) can
be readjusted as desired (usually for an 11 cm trace) without
affecting other adjustments.