Brother MFC-9420CN Service Manual page 251

[ 3 ]-4 CBV Tune Up (Code 45-4)
Function
This function is used when it is required to improve the image defect which is caused by the
OPC belt. The adjustment is implemented by changing the OPC belt bias voltage, and it is
changeable by ±4 steps from the standard value "0".
Always implement the operation when replacing the engine control board.
Operating Procedure
(1) Select NVM Tune UP with using the 4 or 5 key in the initial stage of the factory mode.
After selecting, press the 6 key.
The "45 NVM TUNE UP / ▲ 2 3 4 5 6 7 8 9 A B C D E F G" appears on the LCD.
(2) Select "5" with using the 4 or 5 key and press the 6 key.
(3) Select the optional number with using the 4 or 5 key and press the 6 key.
The adjusted value is written into the NVRAM.
The value can be adjusted by ±4 steps.
(4) Press the 3 key again, and the machine returns to the initial stage of the factory mode.
[ 3 ]-5 FBV Tune Up (Code 45-5)
Function
This function is used when it is required to improve the image defect which is caused by the
transfer drum. The adjustment is implemented by changing the drum cleaner bias voltage,
and it is changeable by ±4 steps from the standard value "0".
Always implement the operation when replacing the engine control board.
Operating Procedure
(1) Select NVM Tune UP with using the 4 or 5 key in the initial stage of the factory mode.
After selecting, press the 6 key.
The "45 NVM TUNE UP / ▲ 2 3 4 5 6 7 8 9 A B C D E F G" appears on the LCD.
(2) Select "6" with using the 4 or 5 key and press the 6 key.
(3) Select the optional number with using the 4 or 5 key and press the 6 key.
The adjusted value is written into the NVRAM.
The value can be adjusted by ±4 steps.
(4) Press the 3 key again, and the machine returns to the initial stage of the factory mode.
[ 3 ]-6 Factory Use (Code 45-6 to 45-G)
Although it is possible to enter the modes from code 45-6 to 45-G, do not use them because
they are for adjusting in the factory.
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