Epson PhotoPC600, Service Manual, Page: 42 / 116

PhotoPC600
Chapter 2 Operating Principles
Rev. A 2-5
SY1 BOARD
SY1 board had 4-bit microprocessor and handles the following the functions.
Table 2-6. Various Circuits of the SY1 Board
No. Circuit Name Function
1 Charge Outputs /CHG On signal to the ST1 board. Also, this circuit monitors
the value of partial pressure of C5412 and controls to stop charging.
Also, it judges if the power supply is AC adapter or battery and
changes the complete time of the battery charge. This prevents the
AC adapter from being heat up.
2 LCD light on Control On/Off of LCD back light. However, characters for explanation
on the LCD are transferred by internal ASIC on CA2 board.
3 Cable Detection When RS-232C cable is installed, this circuit makes all button
functions on the camera invalid.
4 CPU
Communication Perform serial communication with internal main CPU(SPARC).
5 Power supply
control Outputs two wake up signals in order to generate power supply for
digital and analog individually.
6 Battery life
monitor Monitors the AA-size battery life at the voltage level.
7 Video terminal
monitor Monitors if the cable for the video output is installed or not.
8 Card installation
monitor When the power is on, this circuits reads empty raster and calculates
how many pictures can be taken after detecting the existence of the
compact flash card. Also, after the card detection, internal
memory(4M) is invalid.
9 Buzzer control On/Off control of buzzer drive.
10 LCD panel
control Controls the present settings and indication of available photos to take
by the key matrix.
11 LED control Controls all 3 LED drives.
TB1 BOARD
TB1 board is a small board which is mounted with a push button to change over photo
format(modes); Zoom, Panorama, and Multi-frame. The signal to check the button condition is
output periodically from 8-bit CPU on the SY1 board, and mode is changed by recognizing the
change of the button condition.