Validity Lights; Brush Timing; Circuit Breaker Timing; Punch Feed - IBM 1402 Reference Manual

More information about feed rolls is available
in 1402 EC-CEM 54.
2. Failure to read a certain column of the card: This
failure is often the result of an open, somewhere
between the brush and the row bit core in storage.
Check by raising brush assembly from contact
roll and measuring voltage between brush and
ground. A normal brush should read -2Ov (an
open line will be zero).
3. Brushes raised off contact roll.
4. Loose or broken common brush.
5. Bad brush impulse transistors.
6. Incorrect voltage on 20 v supply. Refer to 1402
EC-CEM 56.
Validity Lights
CAUSES
1. Intermittent make of read two, common brush.
2. Cards feeding late. Brush time spans the make of
two impulse CB's.
3. Card feeding skewed. One brush reads two col-
umns.
Brush Timing
Checking of brush timing or any 1402 timing requires
. removal of the 200-position connector in order to
eliminate back circuits.
Circuit Breaker Timings
Excessive timing variations in clutched CB's or brush
impulses can be caused by one of the following:
. 1 .. Loose motor drive belt.
2:
Loose clutched feed roll belt:
3. Loose screws in the clutch pulley assembly.
4. Excessive Hexibility of the clutch pulley shock
mount because of defective bonding.
5. Excessive backlash in clutch (engaged) because
of wear. Replace with a different-sized detent
(P
IN
609737 to 609743).
Refer to the IBM 1401, Customer Engineering
Reference Manual, Service Aids for additional in-
formation.
Punch Feed
Start and Run Data Flow
See Figure 6-4.
6-4
Stop Data Flow
See Figure 6-5.
Punch Stop Lights
Refer to Reader Stop Lights.
Punch Check Lights
Refer to Reader Check. Lights. Check PACB's 9 and
10.
Punch Check Brushes Out of Time
CAUSES
1. All digits out of time. Check tension of second
stepped feed roll.
2. Lower digits (5-9) out of time. Check tension of
sixth feed roll.
Faulty Punch Registration
CAUSES
1. Punching, off one digit: This may be caused by
a loose main drive belt. If the belt is loose, latch-
ing the clutch may cause the belt to jump one
tooth on the first stepped feed roll drive pulley.
2. Variable registration (12 through 9): This may
be caused by:
a. Intermittent feed rolls becoming polished as a
result of running the machine, excessively,
without cards.
b. Insufficient intermittent feed roll tension re-
sulting from bottoming of cam
followe~,
or
from a weak spring.
3. Registration across card, completely off: This
may be caused by a mesh of geneva gears, or by
a loose pin.
4. Slight variance of vertical registration: This may
be caused by:
a. Insufficient pressure shoe spring tension. Be
sure springs have not become polished at the
point where they come in contact with a card.
b. Intermittent roll closing too soon and slightly
moving the card at the end of previous geneva
cycle.
5. Skewed punching and card marking: This can be
caused by trailing edge of card not traveling past
forward aligners at least 1/32".
6. Varying horizontal registration: This can be
caused by aligner adjustment.
Dropping Punches
CAUSES
1. Incorrect interposer to. punch clearance. Clear-
ance should be .005" to .010".