Printronix L5000 Series Maintenance Manual page 371

5. Check the HTS (head thermal sensor).
a. Allow the temperature of the LED to cool well (about 30 C).
b. Put the positive lead of the digital multimeter on pin 10 of IC33 on the I/O
c. Measure the voltage, which should be 3.4 0.5V.
d. Remove connecting jack J21 from the I/O board CN21.
e. Measure the resistance between pins 1 and 2 on the side of the J21.
If the voltage or resistance is not normal, replace the HTS.
6. Check the I/O board.
a. Put the positive lead of the digital multimeter on pin 13 of IC33 on the I/O
a. Measure the voltage when pins 1 and 2 of CN21 on the I/O board are open.
b. Measure the voltage when pins 1 and 2 of CN21 are short circuited, as well.
If voltage is not normal, replace the I/O board.
Troubleshooting
board, and the negative lead on the SG.
Resistance should be about 22KΩ.
board, and the negative lead on the SG.
Voltage should be about 0V.
Voltage should be about 5V.
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