UBI EasyCoder 501 – Service Manual
200
Continued!
26.6
Ribbon Save Device
Troubles
26. TROUBLE SHOOTING, cont'd.
No transfer ribbon is saved
• Check that the running program does not disable the ribbon save
function by means off a
RIBBON SAVE OFF
statement.
• Check that the printed layout contains a sufficient 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 by means of a voltage meter connected to e.g.
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, sequentially.
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 defined by the stepping
rate (magnitude: milliseconds).
