Brother MFC990CW Service Manual page 163

Problem
(4) Light
(5) Dark
(6) Straight or blurred, black or
white, vertical stripes
At the scanner
Check the following components:
- Scanner cover (CIS unit)
- Main PCB
At the printer
Check the following components:
- Ink cartridges
- Head/carriage unit and carriage PCB ASSY
- Main PCB
- Power supply PCB
- Head property data (Refer to
- Maintenance unit
At the scanner
Check the following components:
- Scanner cover (CIS unit)
- Main PCB
At the printer side
• Perform the purge operation (Function code 76) several times to
remove dust or air bubbles from its nozzles. If the problem persists,
replace the head/carriage unit. (Refer to
Check the following components:
- Ink cartridges
- Head/carriage unit and carriage PCB ASSY
- Main PCB
- Power supply PCB
- Head property data (Refer to
- Maintenance unit
Scanner
Check the following components:
- Scanner cover (CIS unit)
- Scanner glass
Printer
• Check whether paper is coming into contact with any components
other than the ones it should during ejecting.
• Check the CR encoder strip for stains or scratches. (If the CR encoder
strip is not hooked properly, correct it.)
4-38
Action to be taken
Chapter 9, Section
Chapter 9, Section
Chapter 9, Section
9.1.4.23.)
9.1.4.27.)
9.1.4.23.)
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