Brother 1660E Service Manual page 88

M-4 Malfunction of control panel switches.
Possible cause Step
Mis-operation 1
Switch 2
Control panel
PCB
Switch flat cable
Main PCB
M-5 Malfunction of buzzer
Possible cause Step
Operational 1 Is the "Buzzer on mode "selected according
error to the operation manual?
(To alternate the buzzer on/off mode selection,
press the MODE switch and select the
"Advanced mode ".)
Main PCB 2 Check the buzzer signal with a oscilloscope.
Is the pulse of 4KHz output?
Buzzer
M-6 "12 COVER OPEN" is displayed even if the upper cover is closed
Possible cause Step
Upper cover 1 Does the upper cover hook press the actuator
of the interlock switch on the main PCB
Main PCB
correctly when upper cover is closed?
Check
Are the switchs operated according to the
operation manual?
When a switch is pressed,does the voltage of
the following signals change from 5V to 0V?
Signal Main PCB
SW8(SEL) P1-8
SW7(MODE/EMULATION) P1-10
SW6(FONT/ECONOMY) P1-12
SW5(FORM FEED/FEEDER) P1-14
SW4(SET/COPY) P1-16
SW3(CONTINUE/SHIFT) P1-18
SW2(DOWN/RESET) P1-20
SW1(UP/TEST) P1-21
Check
Check
Result
No
Yes
No
Panel PCB
---
P1-14
---
P1-12
---
P1-10
---
P1-8
---
P1-6
---
P1-4
---
P1-2
---
P1-1
Result
No
Yes
No
Result
No
Yes
VI - 12
Remedy
Operate the switches
correctly following the
operation manual.
Replace the Main PCB assy.
Replace the control panel
unit or the switch flat cable.
Remedy
Set the buzzer on mode.
Replace the main PCB assy.
Replace the main PCB assy.
Remedy
Replace the upper cover assy.
Replace the main PCB assy.