Ricoh SR210 Technical Bulletin

RICOH Technical B ulletin PAGE: 1/2

M.Iwasa

Model: AD1 (SR210) Date: 16-Apr-97
Subject: MAIN CONTROL BOARD DAMAGE Prepared by: M.Horiike
From: QAC 2nd Field Information Dept. Checked by:
Classification:

Troubleshooting
Mechanical
Paper path
Other ( )

Part information
Electrical
Transmit/receive

Action required
Service manual revision
Retrofit information

No: 29

SYMPTOM

Arcing occurs and a surge current flows into the main control board (P/N A666-5550) of the
AD-1 Finisher when the power cord is plugged into the power source of the main frame
(copier) while power is applied. This may result in possible damage to IC116 and /or IC110
on the main control board.

CAUSE

The main control board has a zener diode in its 5-volt circuit which works to maintain the
voltage (5V) of the circuit by passing the surge current to the ground. However, some
diodes do not work effectively when a large current rushes in, and they allow voltage to
rise over the tolerant voltage level for IC116 and IC110.

SOLUTION

Another type of zener diode has been added to the main control board of the Finisher in
parallel with the existing one to keep the voltage of the 5-volt line by quickly by-passing
the surge current to ground. A modification bulletin will be issued later.

ACTION REQUIRED

The appropriate installation procedure for the Finisher is clearly described in the service
manual and is as follows.

CAUTION

Unplug the copier power cord and turn off the main switch before
starting the following procedure

If the Finisher is installed in accordance with the proper procedure, no problems will
occur.
Please make sure that both the main switch (Red) and the AC switch (Black) are turned
OFF or the copier power cord is unplugged before installing the Finisher.

RICOH Technical B ulletin PAGE: 2/2

Model: AD1 (SR210) Date: 16-Apr-97

Main switch(Red)

No: 29

AC switch (Black)

Note

If only the main switch (Red) is turned off, power is still applied to the Finisher. The AC
switch (Black) should also be turned off to shut down the power to the Finisher.