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Intermec EasyCoder 501 – Service Manual Ed. 7
Chapter 26 Troubleshooting
26.6 Ribbon Save
Device Troubles (not
EasyCoder 501 LL)
No transfer ribbon is saved
• Check that the running program does not disable the ribbon
save function using a RIBBON SAVE OFF statement.
• Check that the printed layout contains a suffi cient length of
“white” as to allow the ribbon save device to react.
• Check the adjustment of the ribbon save mechanism in relation
to the headlift lever, see Chapter 10.6.
• Check that the cable from the Ribbon Save Connection Board
is properly connected to P-8 on the CPU board (see Chapter
17.4).
• Check the current to the DC-motor on connector P-3 on the
Connection Board when a head up or head down operation is
due to be performed (40 V).
• Check that the incoming 24V voltage from the CPU board is
stepped up to 40V using a voltage meter connected to for exam-
ple diode D-1, or pin 14 on IC-2 or IC-3, on the Connection
Board.
• Check that the headlift sensor on the ribbon save mechanism
is clean, in working condition, and properly connected to P-4
on the Connection Board. The 5V voltage on P-4 pin 1 should
switch between high and low when the printhead moves.
Transfer ribbon is not properly rewound
• If the headlift does not work, see above.
• If the rewind unit does not rotate at all, the stepper motor could
be incorrectly connected (P-2 on the Connection Board), or its
drive circuits, IC-2 and IC-3 on the Connection Board could be
damaged.
Check that all pins in the connector of the stepper motor’s cable
are fully inserted.
Test that current is supplied through both motor windings by
means of an oscilloscope whose one probe is to be connected
to GND4 and the other probe to P-2:pins 1, 3, 5, and 7, sequen-
tially. The voltage should switch between 40V and 0V.
Also test the motor current by setting the second probe to each
pin 16 of IC-2 and IC-3. The curve traced by the oscilloscope
should indicate a few tenths of a volt at intervals defi ned by the
stepping rate (magnitude: milliseconds).
• If the measurements above deviate from what is normal, check
the incoming signals ST 1-3 and ST 4-6 to IC-2 and IC-3,
respectively. They are all TTL level signals, and should vary
between low and high with a frequency in the range of kilo-
hertz. If they are found OK, the control and drive circuits IC-2
and IC-3, or the Connection Board, are probably damaged.