Intermec EasyCoder 501 – Service Manual Ed. 7
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Chapter 26 Troubleshooting
26.5 Liner/Batch
Takeup Troubles
• Check that the media is fi tted correctly and that the batch takeup
guide is fi tted described in Chapter 8.5.
• Check the tension of the belts to the takeup unit and to the liner
drive roller (see Chapter 9.3).
• If the takeup unit slips, check if the friction felt inside the
rewind unit has become dried out, see Chapter 9.4.
• If the takeup unit does not rotate at all, the stepper motor could
be incorrectly connected (P-400), or its drive circuits, IC-400
and IC-401 on the CPU 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-400: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-400 and IC-401. The curve traced by the oscillo-
scope should indicate a few tenths of a volt at intervals defi ned
by the stepping rate (magnitude: milliseconds).
If these measurements deviate from what is normal, check the
incoming signals ST 1-3 and ST 4-6 to IC-400 and IC-401,
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-400 and IC-401, or the CPU board, are probably damaged
and whole board needs to be replaced.