Carriage Adjustment With The Tachometer-Generator - IBM 1403 Field Engineering Maintenance Manual

7. Readjust the adjusting-arm as required for the best
line graph of:
a. Double-space 8 lines per inch.
b. Triple-space 6 lines per inch.
8. After this adjustment has been made, adjust the
tape-drive sprocket and the carriage brushes.
EmiHer-Brush Timing (Using Pencil Trace)
1. Be sure that no binds exist when you manually turn
the forms-advance knob with the 6-8 knob in neu-
tral.
2. Set the emitter brushes in the brush holder for a
projection beyond the brush holder of
~l'
(± 3(..").
3. Set up the carriage.
a. Check that the paper is in the carriage.
b. Check that the upper front paper guides are re-
moved.
c. Check that the manual clutch is in 6 lines-per-
inch drive position.
d. Program for triple-space.
4. Start the carriage by pressing the start key.
5. Draw line graphs on the paper.
6. Shift the brush assembly until the line graph ap-
pears as shown in Figure 56.
a. There may be a slight overshoot (maximum al-
lowable Ji'l') on these graphs.
b. Some overshoot may be necessary on triple-space
6 lines-per-inch to prevent excessive pull-in on
double-space 8 lines-per-inch.
7. Check the brush setting for double-space.
a. Set the manual clutch to 8 lines-per-inch drive
position.
b. Program for double-space.
c. Start the carriage and draw line graphs.
8. Readjust the brush assembly as required -for the
best line graph of:
a. Double-space 8 lines per inch.
b. Triple-space 6 lines per inch.
9. After this adjustment has been made, adjust the
tape-drive sprocket and the carriage brushes.
Carriage
Adjustment with the
Tachometer-Generator
The tach-generator (Figure 57) converts the mechan-
ical motion of the carriage into an electrical output
for scoping. This is an extremely accurate method of
adjusting and analyzing the hydraulic unit. If adiust-
ing by the methods of the previous section does not
correct faulty carriage operation, use the tach-
generator.
Before using the tach-generator, check the adjust-
ments of the space and skip needle valves. The forms
tractor and upper and lower drive shafts must also be
correctly adjusted. The tractor shaft relationship is cor-
Upper Tractor Drive - Shaft Assembly
Tach - Generator
Figure 57. Tach-Generator and Coupling
63