• Code: 1-010
• Description: black vertical stripes in the printing.
• Causes: 1. LSU 2. Developer cartridge.
• Remedy: 1. Clean the LSU window. 2. Disassemble LSU and remove foreign matter from the mirror. 3. Replace the developer cartridge if defective.

• Code: 1-020
• Description: White vertical voids in the image.
• Causes: 1. LSU 2. Developer cartridge 3. Fuser 1. Foreign matter on LSU mirror. 2. Foreign matter or toner particles between the developer roller and blade. 3. In case of a defective fuser, voids occur periodically at the top of a black image.
• Remedy: 1. Clean the LSU window with a recommended cleaner. 2. Disassemble LSU and remove foreign material on the mirror. 3. Replace the developer cartridge if defective. 4. Open rear cover and check for fuser rib contamination. Clean if necessary.

• Code: 1-030
• Description: Dark or blurry horizontal stripes occur in the printing periodically.
• Causes: Developer cartridge. 1. Bad Developer roller contacts. 2. The rollers may be stained. -Abnormal image periodicity: 37 mm = Charge roller 31 mm = Supply roller 94 mm = OPC drum non-periodical = Blade
• Remedy: 1. Check all voltages, and adjust as necessary. 2. If black stripes occur at 37mm intervals, check the Charge roller contacts. Clean if necessary, and check position of roller. 3. If blurry black stripes occur at 31mm intervals, disassemble and reassemble the Supply roller contacts. 4. If black stripes occur at 94mm intervals, replace the Developer. - Black stripes may occur due to static electricity. - Black or white stripes may occur due to bad OPC contact stud. In this case, disassemble the gear plate and remove any grease or contamination from the OPC stud. 5. If black stripes occur at irregular intervals, the Blade is defective. Replace the Developer.

• Code: 1-040
• Description: Dark or blurry black or white spots occur periodically.
• Causes: 1. Developer cartridge. 2. Abnormal transfer voltage. 3. The Transfer roller life is near its end. 1. If dark or blurry black spots occur periodically , the rollers in the Developer may contaminated with foreign matter or paper particles. (Charge roller : 37mm interval, OPC drum : 94mm interval). 2. If faded areas or voids occur in a black image at intervals of 94mm, or black spots occur elsewhere, the OPC drum surface is damaged. 3. If a black image is partially broken, the transfer voltage is abnormal or the Transfer roller lifetime has expired.
• Remedy: 1. Cause 1 : Clean the rollers thoroughly. If the OPC drum is stained, clean with a soft cloth dampened in alcohol. 2. Cause 2 : Clean the rollers thoroughly. If problem persists, replace the Developer. 3. Cause 3 : Check transfer voltage, and adjust if necessary. If problem persists, replace the Developer.

• Code: 1-050
• Description: The printed image is light, but free of ghosting.
• Causes: 1. The Toner is nearly empty. 2. Bad contacts on the Developer roller. 3. Ambient temperature is low. 4. Poor contact at the high voltage terminals of the Developer or Engine board due to Toner particle contamination. 5. Agitator gear in the Developer is defective.
• Remedy: 1. Cause 1 : Check the weight of the Developer cartridge, and replace if necessary. When the life of the Cartridge is expired, the weight will be as follows: ML-C800 : 900 grams +- 20 grams ML-C810 : 1050 grams +- 20 grams 2. Cause 2 : Disassemble and reassemble the Developer roller contacts. 3. Cause 3 : In low ambient temperatures, wait one hour after printer is powered on before printing. 4. Cause 4 : Disassemble and clean any main board components stained with Toner or paper particles. 5. Cause 5 : Check that the two hopper gears are visible from the side of the Developer. If not, replace the Developer.

• Code: 1-051
• Description: The printed image is light, but not ghosting.
• Causes: Engine board. 1. Charge voltage(=MHV) on the Engine board exceeds 1350V - 1450V. (Perform DCU diagnostic mode 01 to measure the voltage) 2. No power to the Supply roller or Blade in the Developer.
• Remedy: Check the following parts : U201(KA324), Q211(C1008), T202(Transformer), Resistors, Diodes and etc. in the output and feedback section. Charge voltage(=MHV) Check point: U201; while operating, #12/#13 2.5-2.9V, #14 5.5-8.5V while idling, #13 2.7V, #12/#14 0V Q201 operating voltage; Base 2-2.5V, Emitter 0-1V, Collector 30-60V U203; #1 0V input, #2 0V output

• Code: 1-052
• Description: The printed image is light, with no ghosting.
• Causes: 1. Engine board 2. Main body. 1. Engine board bias (290V - 310V) and supply voltage (490V - 510V) may be low. (Perform DCU diagnostic mode 04 to measure the voltage) 2. Strong ambient light at the manual feeder entrance.
• Remedy: 1. Check the following parts : U201(KA324), Q204(D526-Y), T204(Transformer), U203(SN7407N) Resistors, Diodes and etc. in the output and feedback section 2-1. Check if contrast mode is set to ‘Light’. 2-2. Relocate printer or attach OPC cover sheet, part number JC72-49093A. Remark Bias and supply voltage check point: U203; #9 pulse input, #8 pulse output

• Code: 1-060
• Description: The printed image is dark.
• Causes: Engine board. No Charge voltage in the Engine board. (Perform DCU diagnostic mode 01 to measure the voltage)
• Remedy: Check the following parts : U201(KA324), Q211(C1008), Q201(D526-Y), T202(Transformer), U203(SN7407N), Resistors, Diodes and etc. in the output and feedback region. Clean the high voltage terminal on the Engine and its PBA. Refer to the following information. U201(KA324)'s pin #12, #13 ; 2.5-2.9 V, pin #14 ; 5.5-8.5 V For standby, pin #13 ; 2.7V, pin #12 & #14 ; 0V Q201's operaing voltage ; base=+2-2.5 V, emitter=0-1 V collector=30-60 V U203(7407N)'s pin #1 ; 0V input, pin #2 ; 0V output Remark R201 - R209 temperature instability, changed to metal film type after Feb. 1997, PCB ver. 5.0.