• Code: 17
• Description: Dark image.
• Causes: 1. LSU light power normal? 2. Bias voltage output is high? 3. Video data is always supplied?
• Remedy: 1. Check the rated level and replace. 2. Set to correct voltage. 3. Replace defected board.

• Code: 18
• Description: Background.
• Causes: 1. High voltage output is normal? 2. C/R of toner cartridge is contaminated?
• Remedy: 1. Set to correct voltage. 2. Install a new toner cartridge.

• Code: 19
• Description: Ghost.
• Causes: 1. High voltage output. 2. Pre-transfer lamp. 3. Bad high voltage contact.
• Remedy: 1. Check all high voltage outputs. 2. Check the operation of the pre-transfer lamp. 3. Clean the contaminated contact.

• Code: 20
• Description: Stains on back of paper
• Causes: 1. Contamination of transfer roller 2. Stains of paper path 3. Pressure roller’s contamination
• Remedy: 1. Clean the transfer roller with vacuum cleaner 2. Clean the area of paper path with cloth or air cleaner. 3. Install a new fuser.

• Code: 21
• Description: Poor Fusing
• Causes: 1. Check the paper quality. 2. Check fusing temperature. 3. The machine has been in a low temperature for a long period of time?
• Remedy: 1. Try alternative paper. 2. Check engine controller board. Measure the thermistor voltage to CPU, 2.62V±5% will be measured if the system is working correctly. Check the thermistor contact and thermistor. 3. Re-check the fusing after placing the machine in a warm place for an hour or more.

• Code: 22
• Description: Partial blank image (not periodic)
• Causes: 1. Toner is low? 2. The toner cartridge is out of position?
• Remedy: 1. Install a new toner cartridge. 2. Ensure the toner cartridge is correctly installed.

• Code: 23
• Description: Partial blank image (periodic)
• Causes: 1. Damaged developer unit 2. Defect repeated every 94 mm. 3. Defect repeated every 47 mm.
• Remedy: 1 and 2. Install a new toner cartridge. 3. Install a new transfer roller.

• Code: 24
• Description: Different image density (left and right)
• Causes: 1. Charge roller’s pressure is uneven along it’s length. 2. Dev. roller and OPC or Dev. roller and blade’s pressure is uneven along it’s length. 3. Transfer roller’s pressure is uneven along it’s length.
• Remedy: 1 and 2. Install a new toner cartridge 3. Check left and right spring of transfer roller and the developer spring inside the unit.