Electrical Adjustments; Gain Adjustment; Calibration Adjustment; X-Axis Gear Train Bearings - HP -7035B Technical Manual

c. Remove two clamps holding pulley housing.
drive belt off pulley and pull assembly (A) out of its hold from
bottom. See Figure 5-23.
d. Remove retaining ring from belt pulley shaft. Slide
shaft out of housing.
e. Remove defective bearing(s) and replace with new
bearing, Part No. 1410-0277.
f. Reinstall pulley. Adjust belt tension. See paragraph
5-76.
g. Reassemble.

5-91. ELECTRICAL ADJUSTMENTS

5-92. GAIN ADJUSTMENT

5-93. The gain potentiometers are labeled GAIN on the control
panel and are adjustable wit a screwdriver. If gain in X or Y
channel is insufficient (poor retrace) adjust as follows:
a. Connect low frequency Function Generator to X and
Y input terminals. Set up for triangular output wave of 500 mV
pk/pk at 0.1 Hz.
b. Set X RANGE switch to 100 mV/in. (40 mV/cm), Y
RANGE switch to 1V/in. (0.4V/cm).
5-14
FIGURE 5-23. X-AXIS GEAR TRAIN BEARINGS
Slip c. Turn on recorder.
d. Adjust R237 until minimum retrace error exists.
e. Pen speed should not exceed 1 in./sec (0.4 cm/sec).
f. Similarly, set Y RANGE switch to 100 mV/in. (40
mV/cm), X RANGE switch to 1V/in. (0.4V/cm).
g. Adjust R137 for optimum retrace at 1 in./sec (0.4
cm/sec).

5-94. CALIBRATION ADJUSTMENT

5-95. If recalibration adjustment is required to accommodate
various graph papers, etc., perform the following procedure:
a. Connect DC Standard to X input terminals.
b. Set RANGE switch to 100 mV/in. (40 mV/cm).
c. Adjust ZERO controls to position pen exactly at zero.
d. Apply 1.0 Vdc (1.25V) signal to X input terminals.
e. Adjust R226 to position pen to full scale.