Brother MFC640CW - 1 ] Control Panel Problems; 2 ] Telephone Problems; Troubleshooting Based on Problem Type

9-28 Confidential
9.2.4 Troubleshooting based on problem type
[ 1 ] Control panel problems
Problem Check:
(1) LCD shows nothing.
• Panel-main harness (MFC640CW/DCP340CW)
• LCD flat cable or color LCD (MFC820CW)
• Control panel PCB (MFC640CW/DCP340CW)
• Power supply PCB
• Main PCB
(2) Control panel inoperative.
• Panel-main harness (MFC640CW/DCP340CW)
• Panel-center panel harness or center panel-main harness
(MFC820CW)
• Control panel PCB
• Center panel PCB (MFC820CW)
• Rubber keypad
• Main PCB
(3) Center panel inoperative.
(MFC820CW)
• Panel-center panel harness or center panel-main harness
(MFC820CW)
• Center panel PCB
• Main PCB
[ 2 ] Telephone problems
Problem Check:
(1) No phone call can be made.
• Rubber keypad
• Control panel PCB
• Main PCB
• MJ PCB
(2) Speed dialing will not work.
• Ordinary dialing function (other than the speed and one-touch
dialing)
If it works normally, check the main PCB; if not, refer to item
(1) above.
(3) Dial does not switch between
tone and pulse.
• Main PCB
(4) Telephone does not ring.
• Speaker
• Main PCB
• MJ PCB