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HP Designjet 750C Plus Series Printers - At Power On, all Front Panel LEDs Flash and the Printer Switches Off

	Parts required (part numbers are subject to change)
	Troubleshooting steps
	Drop Detect calibration
	Line Sensor calibration
	Accuracy calibration
	Verify functionality

KRS document number: BPP90010

Last updated: 15-Mar-2002

Minimum skill level: 3

When turning the printer on all front panel LEDs flash and the printer turns off. The most common cause of this issue is the Main PCA and the Service Station. Follow the steps listed below to determine the actual cause of the error and to replace the necessary parts.

Parts required (part numbers are subject to change)

Part Description	Models - C4708A, C4709A	Model - C4708B	Model - C4709B
Service Station Assembly (Required)	C3195-60165	C3195-60165	C3195-60165
Main PCA (Required)	C4708-69001	C4708-69001 or C4705-69001	C4705-69001
Power Supply (Required)	0950-2623	0950-2623	0950-2623

NOTE: If the printer shows no signs of powering up when turned on, replace the Power supply before continuing with any of the Troubleshooting steps listed below.

Troubleshooting steps

1. Turn the printer off.
2. Remove all memory and connections from the Main PCA, leaving the front panel connected.
3. Turn the printer on.
4. If all of the LEDs flash, and the printer turns off again, replace the Main PCA and the Service Station.
5. Following replacement perform the Line Sensor, Drop Detect and Accuracy calibrations (listed below).

Drop Detect calibration

1. Switch the printer on.
2. Press the ENTER button.
3. Use the arrow button to scroll to the Utilities menu display.
4. Press the ENTER button.
5. Simultaneously press the ENTER and the UP ARROW buttons to access the Service Tests submenu.
6. Use the ARROW button to scroll to 1C Drop Detect Cal and press ENTER.
7. The display shows the message Calibrating indicating that the calibration is in progress. Press ENTER when the calibration is complete.
8. Press the PREVIOUS key until Ready is displayed on the printer's front panel.
9. Power cycle printer before running the next calibration.

Line Sensor calibration

1. In the Service Test submenu, scroll to 2C Line sensor cal and press ENTER.
2. The display will show Calibrating Green LED Light, indicating that the calibration is in progress.
3. When the calibration is complete, the display will show Green LED Light # _ _ / press Enter The number shown corresponds to the intensity of the LED light, which will vary for different types of media. The normal range of the number should be between 0 and 56.
4. Press the PREVIOUS key until Ready is displayed on the printer's front panel.
5. Power cycle printer before running the next calibration.

Accuracy calibration

1. Place a sheet of polyester film over the top of the plotter for approximately 10 minutes to let it stabilize to the environmental conditions. Use a sheet of approximately D-size (24 x 36 inches/ 61 x 91 cms). Roll media may also be used. When using polyester film, load it with the matte (dull) side down.

NOTE: If a polyester or matte film is not available use HP Coated media when performing an accuracy calibration.

2. Remove any media already loaded in the plotter before performing the calibration.
3. In the Service Tests submenu, scroll to 3C Accuracy Cal and press ENTER.
4. The Status / Calibrating message is displayed while the plotter is calibrating.
5. When the plotter has finished calibrating, the Load media for calibration message is displayed.
6. Load the media. If using D-size media (HP part #51642A), load the short edge as the leading edge in D-size plotters and the long edge as the leading edge in E-size plotters (E-size media, HP part #51642B).
7. When the media is loaded, the plotter will automatically begin to plot the pattern.
8. A Status / Printing message is displayed while plotting.
9. Remove the media when the plotter has finished plotting.
10. The Create pattern / Measure pattern message is displayed.
11. Press the DOWN ARROW button to select Measure Pattern.
12. Rotate the plot so that the edge with the arrows points toward the plotter, and then reload the plot with the arrow edge print side down.
13. The plotter will load the plot and then measure the alignment marks using the line sensor on the carriage.
14. If the calibration passes, the Success Calibration / Press Enter message is displayed.
15. Press the PREVIOUS key until Ready is displayed on the printer's front panel.
16. Power cycle the printer to save calibration to the EEROM.

Verify functionality

Turn the printer off then on, and print several internal plots "E" or "D" size.

Copyright (C) Hewlett-Packard Co. 2000
This information is subject to change without notice and
is provided "as is" with no warranty.
Hewlett-Packard shall not be liable for any direct,
indirect, special, incidental or consequential damages
in connection with the use of this material.

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