Ricoh A151, Field Service Manual

Page: 38 / 397

Switches
SYMBOL NAME FUNCTION
INDEX
NO.
SW1 Main Switch Supplies power to the copier. 14
SW2
Front Cover
Safety Switch Cuts the ac power line, when the front cover is
open.
13
SW3
Paper Tray
Switch
Detects when the paper tray is set. 1
Sensors
SYMBOL NAME FUNCTION
INDEX
NO.
S1
Scanner Home
Position Sensor Informs the CPU when the 1st scanner is at the
home position.
23
S2
Lens Home
Position Sensor
Informs the CPU when the lens is at the home
position (full size position).
…
FT3213 copier only
25
S3
4th/5th Mirror
Home Position
Sensor Informs the CPU when 4th/5th mirrors assembly is
at the home position (full size position).
…
FT3213 copier only
30
S4
Registration
Sensor 1) Detects misfeeds.
2) Controls the relay roller clutch stop timing.
5
S5 Exit Sensor Detects misfeeds. 16
S6 Relay Sensor
1) Detects when copy paper is set on the
by-pass feed table.
2) Detects misfeeds.
2
S7
Image Density
(ID) Sensor Detects the density of the image on the drum to
control the toner density.
6
S8
Auto Image
Density Sensor
(ADS)
Senses the background density of the original. 19
Printed Circuit Boards
SYMBOL NAME FUNCTION
INDEX
NO.
PCB1 Main Board
Controls all copier functions both directly and
through the other PCBs.
33
PCB2 AC Drive Board
Drives the main motor, exposure lamp, fusing
lamp, and quenching lamp.
27
PCB3
DC Power
Supply Board Converts the wall outlet ac power input to +5 volts,
+24 volts, and a zero cross signal.
36
PCB4
Operation Panel
Board
Informs the CPU of the selected modes and
displays the copier status and condition on the
panel.
8
A151/A152 2-4 FSM