Outline Of The Electronic Parts - Brother LX-300 Service Manual

5.1.2

Outline of the Electronic Parts

Each PCB and the AC adaptor are described below.
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Main PCB
The main PCB is located below the paper guide. It is connected to all PCBs, motors,
switches, and cables.
It converts the unstabilized DC voltages input from the Jack PCB to stabilized +5V
and +24V DC voltages, which are supplied to all controllers.
The Main PCB controls motors, LED indicators, and buzzers according to the
signals input from the detector circuits on the Switch PCB, Paper size sensor PCB,
ENC PCB, and on the Main PCB itself.
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Switch PCB
The Switch PCB is located at the rear of the Body cover. It is connected by a cable
to the Main PCB.
On the Switch PCB are mounted the Two-connection switch, Start key, Stop key,
Continuous key, and Extra border key. LEDs to indicate power ON, continuous
mode, extra and errors; and connectors to connect to push switches of dial switch.
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Jack PCB
The Jack PCB is located at the jack input at the rear of the bottom cover. It supplies
unstabilized DC voltages from the AC adaptor to the Main PCB.
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Paper size sensor PCB (Y-CA sensor PCB)
The Paper size sensor PCB is located on the Y-carriage. The sensor to detect the
document width is mounted on this PCB.
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ENC PCB
The ENC PCB is located on the side of the film cartridge holder. The sensor to
detect the film type is mounted on this PCB.
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Document Detect PCB (PST sensor PCB)
The PST sensor PCB is mounted on the Paper feed roller unit. Sensor on the PCB
detects whether a document is inserted.
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AC adaptor
The AC adaptor converts the input AC voltage to an unstabilized DC voltage. The
AC adaptor plug is connected to the Jack PCB connector.
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