16 Clean both the photoconductor LED and seam sensor using a cotton swab or compressed air.

Run diagnostic 009.

Using an oscilloscope connected to TP3-20 on the PCL board, adjust the signal so that it matches figure A by moving the sensor bracket closer or farther from the photoconductor unit. Figure B illustrates a bad signal. Note that 7ms is the recommended minimum length of time the waveform should maintain 0v; you may have to settle for less. The two small signals prior to the 12v signal are from the smaller holes in the photoconductor unit; the larger signal is from the cutout for the PC sensor.

Figure A

12V

0V

Figure B

12V

0V

7 ms

Is the signal adjusted to match that illustrated in Figure A?

No: Repeat this step until the signal has been adjusted properly.

Yes: Turn to TAG 002: Check & Problem Resolution.

Troubleshooting Analysis Guide (TAGs)

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Image 109
HP C30 manual Figure a 12V