Chapter 3 — Replacing Parts
68 EasyCoder PD41/PD42 Printer Service Manual
Main Board
The main board is a four-layer board with most of its circuits surface-
mounted. Inside the laminate is a combined VCC layer (5V/3.3V/2.5V)
and a GND layer. The front and back sides are signal routing layers. The
following list represents a selection of important components and functions
that are fitted on the main board:
• Processor core
• Thermal printhead driver
• Stepper motor control logic
• Sensor drivers
• Power connector and voltage converters
• Interfaces for external communication, including USB, serial, parallel,
and ethernet
• Interfaces for internal communication with stepper motor, accessories,
and sensors
• 4 MB (PD41) or 8 MB (PD42) flash memory for code storage, fonts,
forms and parameters
• 8 MB (PD41) or 16 MB (PD42) SDRAM for firmware execution and
temporary storage
• 2 kbits serial EEPROM for part and serial numbers and identification
• A/D converter for sensor adjustment
• Compact flash memory card expansion (up to 2 GB)
• CompactFlash Type II (5.0 mm thickness) cannot be used
• CF+ cards may not work
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