IBM 3420 Reference Manual page 40

COMMON ABENDS
(continued)
237 Abend
Machine Possible Causes
Type
3420
Large tape creases detected as gaps (check stubby
bar clearance).
3420 Short records (80 characters) falling within a tape
crease.
3420
Tape edge damage.
3420
E/C 443935 (6250) - Fix for short gap verification
during backspace after a write error caused by
erratic tape motion, not installed.
3420 R/W head forward-to-backward ratio is out of
specifications.
3420
Tape sticking.
3420 Dirty capstan.
3803 Missing Suppress Out, intermittently breaking
channel/command word (CCW) chain, updating
the count but not losing a record.
3803
Defective 01 A-B3F2 inbound tag card XC700.
3803
ECA079 - Unexpected interrupt with status
=
'00' from a non-two channel switch in multiple
CPU 2X, 3X, 4X, installation.
36