01/022-118825/8830 Printer LL-90 Overtoned Fault RAP, LL-91 UndertonedStatus Indicator RAPsProcedureWith the printer in an LL-90 fault condition, enter diagnostic code [9-22] and then press YES, inorder to enable the printer to function with an LL-90 fault condition. Enter the code [0361] inorder to exit the diagnostics mode. Run 3 test prints [9-55 Pattern 5]. The LL-90 code is dis-played as the print is being made.Y NComplete the service call.Use the last print to check the image density. The image density of the 1.0 Solid Square inthe center of the Test Pattern [0955-5] is equal to or less than the 1.20 Density Square onthe Output Reference SIR 495.1.Y NPerform the Tone-Down Procedure [09-06. If the printer does not tone-down, perform theImage Density Adjustment. Go to ADJ 9.3.Enter the code [9-21-4] in order to switch on the Main Drive Motor and the Toner Sensor circuit.Connect the (+) meter lead to the Toner Sensor A22Q1P1-2 and the (-) meter lead toA22Q1P1-4. There is +15 VDC present.Y Nheck for an open or short circuit to ground in the wires connected to A22Q1P1-2 andA22Q1P1-4. If the wires are ok, replace the Main PWB, A3, PL 1.1A.Connect the (+) meter lead to the Main PWB A3J303-4 and the (-) meter lead to ground.There is +5.2 to +6.0 VDC is present.Y NConnect the (+) meter lead to the Toner Sensor A22Q1-1 and the (-) meter lead toground. There is greater than +0.2 VDC present.Y NDisconnect Toner Sensor A22Q1P1 from A22Q1J1. Connect the (+) meter lead tothe Main PWB A3J303-16 and the (-) meter lead to ground. There is greater than+0.2 VDC present.Y NReplace the LVPS, A5, PL 1.1APL 1.1A. If the problem persists, replace theMain PWB, A3,Check for an open or short circuit to ground in the wires connected to A22Q1-2 andA22Q1-4. If the wires are OK, replace the Toner Sensor A22Q1, PL 9.9. Run [9-21-6Toner Sensor Calibration.Check for an open or short circuit to ground in the wire connected to A22Q1P1-3. If thewire is OK, replace the Toner Sensor A22Q1, PL 9.9. Run [9-21-6 Toner Sensor Calibra-tion.Replace the Main PWB, A3, PL 1.1A.LL-91 Undertoned Fault RAPNOTE: Go to BSD 9.7 while using this RAP.The status code LL-91 is displayed when the logic detects that the toner concentration is signif-icantly less than the Control Point value.The Toner Control System is designed to maintain the Toner Concentration within an accept-able operating range. The Control Point operating range is from 5.2 to 6.0 VDC. The TonerSensor continuously senses the Toner Concentration. A change in the Toner Concentrationresults in a corresponding change of the Sensor signal. As the Toner Concentration decreases,the Toner Sensor signal voltage increases. The logic monitors the Toner Sensor signal.LL-91 indicates that the logic detected that the toner concentration decreased greater than theallowable limit.The problem may occur if there is a problem with the toner dispensing or the developer mixingsystems.Initial Actions• Examine the Toner Cartridge to ensure that the Cartridge is not empty and is installed cor-rectly.• Check the Cartridge for damage and ensure that the seal is secured to the Cartridge inthe correct location.• (Figure 1 ) Ensure that the Developer Drive Coupling is in good condition and is engagedfully.• (Figure 2) Ensure that the Developer Housing Auger and Drive Gears are not damagedand are installed correctly.• Check that all the connectors between the Toner Sensor, A22Q1, and the Main PWB, A2,are seated correctly.ProcedureWith the printer in an LL-91 fault condition, enter diagnostic code [9-22] and press Yes, in orderto enable the printer to function with an LL-91 fault condition. Enter the code [0361] in order toexit the diagnostics mode.
