Brother DCP6690CW Service Manual page 157

Problem
(9) Random missing dots
(10)White horizontal streaks
(11)Stained leading edge of
recording paper
Printer
• Perform the purge operation (Function code 76) several times to
remove dust or air bubbles from its nozzles. (Refer to
Section 9.4.24.)
• Check the ink cartridges. If any cartridges have run out of ink, replace
them.
• Check that the carriage-head flat cable is connected to the carriage
PCB.
• Replace the head/carriage unit.
• Check the connection of the head flat cables on the main PCB. (If
either of those cables is broken or damaged, replace it.)
• Replace the main PCB.
• Clean the head caps and wiper of the maintenance unit with a Rubycel
stick. For the cleaning procedure, refer to
"CLEANING THE MAINTENANCE UNIT."
• Replace the maintenance unit.
• Perform the purge operation (Function code 76) several times to
remove dust or air bubbles from its nozzles. (Refer to
Section 9.4.24.)
• Replace the head/carriage unit.
• Check the paper feed-related rollers.
• Perform the print head skew compensation with the head skew adjuster
knob. Refer to Chapter 7, Section 7.2, [ 4
• Clean the head caps and wiper of the maintenance unit with a Rubycel
stick. For the cleaning procedure, refer to
"CLEANING THE MAINTENANCE UNIT."
Printer
• For duplex print models: Change the special duplex copy settings using
the steps below.
1) Press Duplex Copy on the machine's panel.
2) Press On to turn on the duplex setting.
3) Press Advanced.
4) Press DX1 or DX2.
(DX1 helps avoid paper jams when copying by allowing more time
for the ink to dry. DX2 allows more time for the ink to dry while also
using less ink.)
• Perform a head cleaning operation.
• Check that the head/carriage unit is set into place.
• Check the height adjustment mechanism of the head/carriage unit
(Refer to Chapter 3, Section
• If the "head-platen gap offset" is enabled with assurance mode switch
AMS 02 (Function code 88), align the vertical print lines (Function
code 65). (Refer to Chapter 9, Section 9.4.29 and
4-45
Action to be taken
Chapter 8, Section 8.2
].
Chapter 8, Section 8.2
3.2.2.3.)
Chapter 9,
Chapter 9,
9.4.18.)
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