IBM 1403 Field Engineering Maintenance Manual page 60

5. Adjust the needle valve to cause the detent to nip
as follows:
a. Hold the screwdriver against the detent arm at
the notch.
b. Back off on the center left screw (Figure 50)
until you feel the detent nip the detent wheel.
The impact will be transmitted through the
screwdriver.
6. Adjust the needle valve to stop the detent from
nipping.
a. From the nip condition, close the needle valve
only far enough to bring the detent to rest
against the backstop. Following this, you should
still feel hydraulic-pump vibration when placing
your finger on the tail of the detent.
b. Tighten the lockscrew (the center right screw).
7. After this adjustment has been made, the skip
needle valve must be adjusted.
Skip Needle-Valve Adiustment
(2-S.peed Carriage Machines)
Note: Model 6 Printers are single-speed machines. In carriages
on Model 6 printers, the adjusting screw on the skip needle
vaive shouid be fuHy dosed and locked.
1. The space needle valve must be adjusted.
2. Set up the carriage. Make sure:
a. There is no paper in the carriage.
b. The forms-stop contacts are closed.
c. The manual clutch is engaged.
d. U npunched carriage tape is installed.
e. The tape brushes are lowered.
3. Start the carriage in a programmed skip-to-1 before
print. This should result in a skip-to-1 at high speed
with no stop impulse available.
4. Loosen the lockscrew for the skip needle valve (the
front right screw, Figure 50).
5. Adjust the skip needle valve as foHows:
60
a. Hold a screwdriver against the detent arm at the
notch.
b. Back off on the front left screw (Figure 50)
until you feel the detent nip the detent wheel.
The impact will be transmitted through the
screwdriver.
(1)
If no nipping is detected after turning out a maxi-
mum of five turns, stop the carriage motor so that the
hydraulic pumps are not moving. Turn down on the
front left screw until it is dosed. Then back off five full
turns on this screw, Tighten the locks crew (the front
right screw).
(2) If nipping is detected, adjust the needle valve to
stop the detent from nipping.
c. From the nip condition, close the needle valve
only far enough to bring the detent to rest against
the backstop. Following this, you should still feel
hydraulic-pump vibration when placing your
finger on the tail of the detent.
d. Tighten the lockscrew (the front screw). Stop
the carriage.
e. After this adjustment has been made, the bypass
needle valve must be adjusted.
Bypass Needle-Valve Adiustment (Using Pencil Trace)
1. The following should be adjusted:
a. The space needle valve.
b. The skip needle valve (on machines with the
2-speed carriage).
2. Be sure that the following adjustments are correct:
a. The tractors.
h. The tractor drive shafts.
3. The E-I emitter and circuits controlling triple-
space must be adjusted sufficiently to provide con-
sistent triple-spaces when the detent is held dis-
engaged.
4. Set up the carriage.
a. Place the paper in the carriage.
b. Program for triple space.
c. Engage the manual clutch in the 6-lines-per-
inch position.
d. Remove the upper front paper guides.
5. Loosen the lockscrew for the bypass needle valve
(the rear right screw, Figure 50).
6. Tum in on the bypass needle valve (rear left
screw) until it is closed, then
turn it
out
~
tum.
7. Disengage the detent arm by pressing down in
the notch with a large screwdriver.
8. Start the carriage by pressing the start key.
9. Adjust the bypass needle valve as follows:
a. Draw line graphs across the paper while it is
feeding.
(1) Move the pencil at a rate that will show from
four to ten triple spaces on a sheet 11" wide.
(2) Too much pencil pressure can cause a drag on
the paper, and therefore, an erroneous graph.