Adjust Thermal Balance; Check Vertical Linearity - Tektronix 7623A Instruction Manual

Calibration—-7623A/R7623A Service
d. CHECK—That the deflection of the seven center traces is six divisions +0.06 division. Note the
exact deflection for part h of this step.
e. ADJUST—Vertical Gain adjustment R2446 (see Figure 8-20) for exactly six divisions of deflection
for the center seven traces.
f. Remove the signal standardizer from the left vertical compartment and insert it into the
right vertical compartment.
g. Set the VERT MODE to RIGHT.
h. CHECK—That deflection of the seven center traces is the same as step 2d within 1% (six divisions
£0.06 division if R2446 was adjusted).
i. READJUST~-Vertical Gain adjustment R2446, if necessary, for optimum gain for both vertical
compartments.
j. Remove the signal standardizer from the right vertical compartment and insert it into the
left vertical compartment.
3. Adjust Thermal Balance
NOTE
If the instrument being calibrated is not equipped with the readout feature, set the Thermal
Balance contro! R2527 for a reading of +8.65 volts measured at the R2527 end of C2524 (see
Figure 8-20), and omit this part.
a. Set the signal standardizer Test switch to + Step Resp and Amplitude to minimum. Position
the trace to the top graticule line.
b. Install an amplifier unit in the right vertical compartment.
c. Set the VERT MODE to ALT. Position the amplifier-unit trace on the bottom graticule line.
Set the time-base unit for a sweep rate of 10 milliseconds/division.
d. Set the 7623A INTENSITY to midrange and advance the READOUT INTENSITYtil! the readout is
viewable.
e. ADJUST--Thermal Balance contro! R2527 (see Figure 8-20) for minimum vertical movement of the
displayed readout characters. If appreciable adjustment is required, recheck the Vertical Gain adjustment
in step C-2.
4. Check Vertical Linearity
a. Remove the amplifier unit from the right vertical compartment.
b. Set the VERT MODE to LEFT.
c. Set the signal standardizer Test switch to Vert or Horiz + Step Resp and the Rep Rate to
100 kilohertz.
d. Set the time-base unit for a triggered display at a sweep rate of one millisecond/division.
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