Brother Laser MFC-4800, Service Manual

Page: 103 / 205

5-14
5.3.8 Receiver Volume Adjustment (applicable to the American version only)
Function
The facsimile equipment may switch the handset receiver's volume between three levels--Low,
High, and Amplify*.
(*Amplify level: Extra-high volume for users who are deaf or hard of hearing.)
The volume at Low or Amplify level is fixed and not adjustable. The volume at High level will be
influenced by the characteristics of the FET on the main PCB, so it requires fine adjustment
according to the procedure given below.
Operating Procedure
(1) Connect the telephone line cord to the modular jack of the facsimile equipment and the
telephone wall socket.
(2) Pick up the handset and listen to the dial tone. If the receiver volume is not appropriate,
proceed to the following steps:
(3) Press the 1 and 6 keys in this order in the initial stage of the maintenance mode.
The LCD shows the current receiver volume (default: High).
(4) If the current receiver volume is not High, use the up or down arrow key to choose High.
(5) Press the Fax Start key.
The equipment enters the receiver volume adjustment mode and shows the PWM duty ratio at
the right end of the LCD.
(6) Adjust the receiver volume by using the 1 , 3 , 4 , or 6 key.
1 key: Decrease 10H
3 key: Increase 10H
4 key: Decrease 1H
6 key: Increase 1H
(7) To escape from the receiver volume adjustment mode, press the Set key.
The LCD shows the "PWM SETTING." One second later, the LCD returns to the screen
shown in step (3).
(8) To return the equipment to the initial stage of the maintenance mode, press the Stop key.
Low level
High level (default)
Amplify level
Up arrow key
Down arrow key