Known Trouble Tips - IBM 1620 Manual

KNOWN TROUBLE TIPS
Card Reader Punch
FEED TROU BlE
1. Check feed knives for a I ignment and travel, and
feed rolls for adequate pressure.
2. The fai lure of the last few cards to feed can resul t
from too wide an angle between the card weight
and the card weight spring. This can be corrected
by using an older card weight or by forming the
springs. Tension of the hopper contact will
accentuate this condition.
3. Card dust and shavings in the feed or dirt on the
feed rolls can result in read-in errors. Operations
which require overpunching result in fine card
shavings which may not follow the chip chute and
can float around in the transport and relay areas.
4. Care should be exercised in replacing the chip
chute. It can be inserted backward covering the
chute opening and causing chips to pile up inside
the machine.
5. A loose feed roll drive belt can cause read-in
errors. If the belt is too loose, it can jump a
tooth on the first feed roll drive gear and cause
the card to read one digit low for the card cycle.
The trouble will be intermittent, for on the next
card cycle it will be back in time. loose-belts
can also cause CB timing variation and results in
read-in errors.
6. The contact rolls setscrews should be checked to
ensure that the roll is being positively driven. A
dragging contact roll can cause read-in errors as
well as jamming problems.
7. Pressure shoes should be checked for sufficient
tension and even drag. The shoe surfaces tend
to become pol ished. This trouble can be corrected
by increasing the spring tension or roughening the
surface of the shoes. lack of, or uneven, tension
can cause off-punching as well as jamming.
8. If jamming is experienced at the fOlWard al igners,
the edge of the al igners should be examined. If
the surfaces are not smooth, they should be honed.
9. If the die retracting pin spring tension is insuffi-
cient, it is possible for the pin to bounce in the
card line. This will show as a nick on the card
edge and again result in off-punching as well as
jamming.
lubriplate (IBM #70), PiN 435682 has been
helpful in reducing belt and pulley wear.
3.20
BRUSH TROUBLE
1. Check the reading brushes for correct timing
and tracking.
2. Brushes should be centered over the contact roll
to fac il itate straight feeding of the card and
prevent it from being forced up or down into the
card guides. Bent brushes can catch the card
edge or holes in the card. Care in removing
and replacing the brush blocks in the machine
will reduce the bent brush problem.
3. Intermittent read failures can occur if brushes
rub the brush separator. Over-all centering of
brushes in the brush separator slots is accompl ished
by shifting the brush separator. Individual brushes
which are misaligned must be individually aligned
for proper centering within the separator slots.
This should resul t in the brushes tracking through
the center of the hole. Any brush separators
which do not permit uniform tracking at the
extreme ends of the card should be replaced.
4. Read-in troubles can resul t from brush blocks
which have not been locked in place. Always
check the brush blocks on a read-in trouble call.
5. A loose feed roll common brush or a lack of a
common brush tension can result in read-in errors.
6. Also check for:
a. loose, cracked or broken Quick Disconnect
blocks.
b. loose individual terminals from brush cable
or between Quick Disconnect and brush
blocks.
c. Examine and flex brush cables to check for
open or shorted wires.
d. Carefully examine the brushes for bent, broken
(electrical shorts) or short (brush) strands. A
short strand can be a real trouble-maker and
is difficult to see.
PUNCH TROUBLE
10
Off-punching cards by one digit can be caused
by a loose picker knife drive belt. This can
happen when the clutch latches and the belt
jumps one tooth on first feed roll drive pulley.
2. If cards are nicked on the leading edge by the
punches, check the timing of the first stepped roll.
3. If vertical registration varies sl ightly, check
pressure shoe springs for tension. Check that
pressure shoes have not become polished where
they contac t the card.
4. Varying vertical registration can be caused by an
intermittent roll closing too soon and moving the
card slightly at end of the previous Geneva cycle.