Printronix 108525-001, Maintenance Manual

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5-21 P6040/P6080 Corrective Maintenance
5-15. Paper Motion Sensor (Figure 5-11)
a. Test
ă1. Verify that jumper enabling paper motion sensor is installed (see User's Reference ManĆ
ual).
ă2. Load paper and run several top-of-form operations.
ă3. Connect exerciser. Set exerciser to self-test and run several pages. Look for error mesĆ
sages.
ă4. If no error messages occur, the sensor and its circuit are functioning correctly.
b. Position Check
ă1. Open cover (1).
ă2. Remove paper from printer.
ă3. Open gate of left tractor (2) and inspect sensor (3).
ă4. If both apertures are visible and unobscured, sensor position is correct.
ă5. Perform final position check.
(a) Install paper in tractors and close gates.
(b) Connect oscilloscope to junction of C12 and R39 (P6040) or C2 and R13 (P6080)
on power supply PCBA; this is the input to the paper motion detector. Set oscilloĆ
scope to between 0.1 and 1 Volt per division as required to display entire vertical
portion of waveform. Set sweep speed at about 10 mSec/division.
(c) Rotate vertical position knob while observing scope for a maximum signal level of
not less than 150 mV peak to peak. If amplitude is less than 150 mV, loosen mountĆ
ing nut (4) and move sensor (3) toward or away from paper until a maximum signal
level is obtained. Some high gain sensors will provide 2 or 3 V amplitude in some
cases. Tighten mounting nut (4) finger tight.
(d) Rotate vertical position knob while observing scope for a minimum signal level
(with a paper hole over the sensor window - Approximately 100 mV or less).
(e) Using fingers or an orange stick, rotate the sensor (3) back and forth a few degrees
on the mounting stud to obtain an even lower signal level than in (d) above.
(f) When lowest level is achieved, hold sensor (3) in position and tighten nut (4).
(g) Repeat (c) above to ensure that maximum level is still 150 mV or more. Readjust
if/as necessary.
(h) Slew paper several times with TOF button to check for false paper jams. If false
paper jams occur, replace sensor and repeat (c) through (g) above.
ă6. Replace covers per paragraph 5-17b.
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