Brother SCANNERII, Operation, Service Manual & Parts List

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IV . Diagnosing a Breakdown in the Electrical System
Diagnosing a breakdown in the electrical components
* See the illustration for locations which should be checked.
Situation Locating the Problem Solutions
•
No buzzer sounds when the
main power switch is
pressed, and nothing
appears on the LCD display.
•
Have the batteries been inserted
correctly?
‚
Has the fuse blown?
ƒ
Are the battery holder and main PC
board assembly connected, or has the
wiring to the main PC board assembly
been disconnected?
„
If the AC adaptor has been plugged into
a wall outlet, is the DC plug output
between 9.5 and 14 VDC (if an AC
adaptor is being used)?
…
Other Points to Check
•
Check carefully.
‚
Replace the fuse.
(First check to see why the fuse
has blown, and correct the
problem.)
ƒ
Replace the terminal plate
assembly.
„
Replace the AC adaptor.
…
Replace the main PC board
assembly.
‚
The LCD display does not
function correctly.
•
Has the LCD contrast adjustment knob
been adjusted?
‚
Have the LCD module and the main PC
board assembly been connected, or are
there any disconnected lead assemblies?
ƒ
When the LCD module connector (P5) is
disconnected from the main PC board
assembly, is the voltage between 1 and
2, and between 3 and 2, correct?
Between 1 and 2: -8 to -20 VDC
Between 3 and 2: 5 VDC
„
Check other points carefully.
•
Check carefully.
‚
Replace the lead assembly.
ƒ
Replace the main PC board
assembly.
„
Replace the main PC board
assembly or the LCD module.
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