Brother 7840 W User Guide

Troubleshooting and routine maintenance111
B
CAUTION 
We recommend that you place the drum 
unit and toner cartridge assembly on a 
clean, flat surface with a sheet of 
disposable paper or cloth underneath it in 
case you accidentally  spill or scatter toner.
 
cIf you cannot remove the drum unit and 
toner cartridge assembly easily, do not 
use extra force. Instead, lift the scanner 
cover.
 
Use both hands to carefully pull the 
jammed paper up and out of the output 
tray opening.
 
dClose the scanner...

112
Paper is jammed at the back of the 
machine
B
aOpen the front cover. 
bSlowly take out the drum unit and toner 
cartridge assembly.
 
CAUTION 
We recommend that you place the drum 
unit and toner cartridge assembly on a 
clean, flat surface with a sheet of 
disposable paper or cloth underneath it in 
case you accidentally spill or scatter toner.
 
cOpen the back cover (back output tray).  
dPull the tabs toward  you to open the 
fuser cover (1). 
 
ePull the jammed paper out of the fuser 
unit....

Troubleshooting and routine maintenance113
B
Paper is jammed inside the drum unit 
and toner cartridge assembly
B
aOpen the front cover. 
bSlowly take out the drum unit and toner 
cartridge assembly.
 
CAUTION 
We recommend that you place the drum 
unit and toner cartridge assembly on a 
clean, flat surface with a sheet of 
disposable paper or cloth underneath it in 
case you accidentally  spill or scatter toner.
 
cPush down the green lock lever and take 
the toner cartridge out of the drum unit....

114
ePut the toner cartridge back into the 
drum unit until you hear it lock into place. 
If you put it in correctly, the green lock 
lever will lift automatically. 
 
fPut the drum unit and toner cartridge 
assembly back in the machine.
 
gClose the front cover.
Routine maintenanceB
WARNING
 
Use neutral detergents.
  
DO NOT use any flammable substances, 
spray or organic solvent/liquids containing 
alcohol/ammonia to clean the inside or 
outside of the machine. Doing this may 
cause a fire or...

Troubleshooting and routine maintenance115
B
cWipe the outside of the machine with a 
soft cloth to remove dust.
 
dRemove any paper that is in the paper 
tray.
eWipe the inside and the outside of the 
paper tray with a soft cloth to remove 
dust.
 
fRe-load the paper and put the paper tray 
firmly back in the machine.
gPlug the machine’s power cord back into 
the electrical socket first, and reconnect 
all cables and telephone line cord. Turn 
on the machine.
Cleaning the scanner glassB
aTurn off the...

116
dPlug the machine’s power cord back into 
the electrical socket first, and reconnect 
all cables and telephone line cord. Turn 
on the machine.
Note
In addition to cleaning the scanner glass 
and glass strip with a soft lint-free cloth 
moistened with water, run your finger tip 
over the glass to see if you can feel 
anything on it. If you feel dirt or debris, 
clean the glass again concentrating on 
that area. You may need to repeat the 
cleaning process three or four times. To 
test, make a copy...

Troubleshooting and routine maintenance117
B
 
WARNING 
HOT SURFACE
After you have just used the machine, some 
internal parts of the machine will be 
extremely hot. To prevent injury, when you 
open the front or back cover (back output 
tray) of the machine, DO NOT touch the 
shaded parts shown in the illustration.
 
 
 
CAUTION 
To prevent damage to the machine caused 
by static electricity, DO NOT touch the 
electrodes shown in the illustration.
 
 
 
We recommend that you place the drum 
unit on a...

118
dPut the drum unit and toner cartridge 
assembly back in the machine.
 
eClose the front cover.
fPlug the machine’s power cord back into 
the electrical socket first, and then plug 
in the telephone line cord.
Turn on the machine.
Cleaning the corona wireB
If you have print quality problems, clean the 
corona wire as follows:
aTurn off the machine. Unplug the 
telephone line cord first, disconnect all 
cables, and then unplug the power cord 
from the electrical socket.
bOpen the front cover. 
cSlowly...

Troubleshooting and routine maintenance119
B
dClean the corona wire inside the drum 
unit by gently sliding the green tab from 
right to left and left to right several times.
 
CAUTION 
Be sure to return the  green tab to the home 
position ( a) (1). If you do not, printed pages 
may have a vertical stripe.
 
ePut the drum unit and toner cartridge 
assembly back in the machine.
 
fClose the front cover.
gPlug the machine’s power cord back into 
the electrical socket first, and then 
reconnect all cables...

120
Cleaning the drum unitB
If you have print quality problems, clean the 
drum unit as follows.
aTurn off the machine. Unplug the 
telephone line cord first, and then 
unplug the power cord from the 
electrical socket. 
bOpen the front cover. 
cSlowly take out the drum unit and toner 
cartridge assembly.
 
CAUTION 
We recommend that you put the drum unit 
and toner cartridge assembly on a clean, 
flat surface with a sheet of disposable 
paper or cloth underneath it in case you 
accidentally spill or...