Product

Platform

PC

Operating system

Windows

Background

• Whenever proofing media is not staying on the drum due to vacuum problems
• If vacuum error messages appear in the PC controller

Requirements

• PC controller software version 3.70.02
• 8up proofing media
• 4up proofing media

Procedure

1. Verify that PC controller software version 3.70.02 is installed.
   Note: To verify the software version, from the PC Controller, select Utilities>Machine Info. The software version appears on the monitor.
2. Verify that there is no media on the drum.
3. Set the values for the following parameters as follows:
   • Maximum Drum Vacuum Pressure Before Blanket Loading (mbar) = -350
   • Minimum Drum Vacuum Pressure Before Blanket Loading (mbar) = -130
   Note: To access the parameter, do the following:
   1. From the PC Controller, select Utilities>Hardware.
   2. In the Hardware tree, double-click Loading System, and then right-click Loading System.
   3. In the Properties dialog box, double-click Load Blanket and locate the relevant parameter.
4. Access the Drum Vacuum Analog Detector dialog box.
   Note: To access the Drum Vacuum Analog Detector dialog box, do the following:
   1. From the PC Controller, select Utilities>Hardware.
   2. In the Hardware tree, double-click Drum System>Drum Detectors>Drum Vacuum Analog Detector. The Drum Vacuum Analog Detector dialog box appears.
5. Activate the drum vacuum pump and allow it to operate for approximately 15–20 seconds.
   Note: To activate the drum vacuum pump, do the following:
   1. From the PC Controller, select Utilities>Hardware.
   2. In the Hardware tree, double-click Drum System>Drum Solenoids>Drum Vacuum Pump.
   3. In the Drum Vacuum Pump dialog box, click Start. The drum vacuum pump is activated.
6. Check the vacuum level in the Drum Vacuum Analog Detector dialog box and, when the vacuum level has stabilized, verify that it is between -350 and -130. If the level is:
   • Higher: The drum vacuum holes are clogged. Clean the holes as described in Periodic Maintenance.
   • Lower: There may be a leak in the vacuum system, or the filter may need to be replaced.
   Note: Verify the value for the Drum Vacuum Pressure Valve Before Blanket Loading parameter, and write it down. For this procedure, we will refer to this value as Y.
7. Deactivate the drum vacuum pump by clicking Stop in the Drum Vacuum Pump dialog box and then load an 8up carrier.
8. Open the rear door and verify that the carrier is properly attached to the drum. Pay close attention to:
• The area near the drum pin
• The area around the vacuum grooves

Note: If the “drum vacuum pump is not in the allowed range” error message appears in the PC controller, ignore it and continue the procedure.

9. In the Drum Vacuum Analog Detector dialog box, verify the current value for the drum vacuum analog detector, and write it down. For this procedure, we will refer to this value as X.
10. Subtract Y from X. For this procedure, we will refer to the difference as Z1 (X-Y=Z1).
11. Access the Drum Vacuum Difference for 8up Blanket parameter.
    Note: For example, if X=-320, and Y=-265, then the numerical value for Z1is -55.
    (-320)-(-265)=-55
    The value should be a negative number.
12. Leave the carrier on the drum and load an 8up receiver.
    Note: Use a cheater, as required.
13. Perform steps 9 and 10, but this time, we will refer to the difference as Z2.
14. Access the Drum Vacuum Difference for 8up Receiver parameter and enter Z2's numberical value.
    Note: For example, if X=-720, and Y=-265, then the numerical value for Z2 is -455. That is, (-720)-(-265)=-455.
    The value should be a negative number.
15. Leave the carrier and receiver on the drum and load an 8up donor.
16. Perform steps 9 and 10, but this time, we will refer to the difference as Z3.
17. Access the Drum Vacuum Difference for 8up Donor parameter and enter Z3's numberical value.
    Note: For example, if X=-720, and Y=-265, then the numerical value for Z3 is -455. That is, (-720)-(-265)=-455.
    The value should be a negative number.
18. Unload the donor and the receiver, and then load a 4up receiver.
19. Perform steps 9 and 10, but this time, we will refer to the difference as Z4.
20. Access the Drum Vacuum Difference for 4up Receiver parameter and enter Z4's numberical value.
    Note: For example, if X=-720, and Y=-265, then the numerical value for Z4 is -455 (-720)-(-265)=-455.
    The value should be a negative number.
21. Leave the 4up receiver on the drum and load a 4up donor.
22. Perform steps 9 and 10, but this time, we will refer to the difference as Z5.
23. Access the Drum Vacuum Difference for 4up donor parameter and enter Z5's numerical value.
    Note: For example, if X=-720, and Y=-265, then the numerical value for Z5 is -455 (-720)-(-265)=-455.
    The value should be a negative number.

Test

1. Remove all cheaters and close all doors, as required.
2. Unload all media, including the carrier.
3. Load a carrier and verify that no vacuum error messages appear in the PC controller.
4. Load a receiver and verify that no vacuum error messages appear in the PC controller.
5. Load a donor and verify that no vacuum error messages appear in the PC controller.

See also

• Installing PC controller software version 3.70.02 in the Lotem Spectrum and the Lotem Quantum Spectrum
• PC controller software version 3.70.02 compatible firmware

Technical contact(s)

Nir Peleg
See the Escalation page for escalation contacts.

Date submitted

28 Aug 2002