C486 Main Board - Epson Stylus C82 Service Manual

EPSON Stylus C82

2.2.2 C486 MAIN Board

Table 2-4. C486 MAIN Board Major Components and Primary Functions
IC Location
8 Mbit ROM program for CPU provided with CG table, 3.3V
ROM IC1
drive (not DOS compliant)
Transceiver IC for the Centronics I/F response to IEEE1284 and
Transceiver IC3
ECP more, Data transfer by DMA, 3.3V drive
Formed reset signals shown below.
Reset regulator IC4
1. Dropping 42V line to 36.3V, 2. Dropping 5V line to 4.2V
4 Mbit RAM 2-CAS type, 16 bit bus, 5V and 3.3V drive provide
D-RAM IC5
page access functions.
EEPROM IC6 1 kbit capacity for default setting or adjusted value.
For driving both CR and PF motors, PWM control by program
Motor Driver IC8
timer, 5V regulation, 42V drive
Head Driver 1 IC9 For creating trapezoidal waveform, 5V drive
CPU (equivalent of H8S/2323), Internal 8Kbit RAM, Internal
ASIC IC10
MASK ROM, 24MHz, 3.3Vdrive
Head Driver 2 Q2, Q3 Based on IC9 control, trapezoidal waveform creates, 42V drive
OPERATING PRINCIPLES
Function
Electrical Circuit Operating Principles
Revision A
19