Brother KE-430F Service Manual page 166

15. ELECTRIC MECHANISM
Error status #8 Error code appears on the display when the foot switch is depressed.
Probable causes
1. If the work clamp pulse motor
does not operate and "E300" is
displayed, there is a malfunction of
the power PCB.
2. If the work clamp pulse motor
does not move and "E300" is
displayed, there is a malfunction of
the main PCB.
3. If the work clamp pulse motor
moves slightly and "E300" is
displayed, there is a malfunction of
the encoder.
4. If the work clamp pulse motor
does not move and "E300" is
displayed, there is a malfunction of
the pulse motor and cord.
156
Check/ repair/ adjust
Disconnect connectors P1 (POWER2) and P24
(POWER1) from the main PCB, and then turn on
the power switch and check LD1 (red) on the
power PCB.
OK if illuminated.
After checking, turn off the power switch, wait for
one minute or more, and then insert P1 and P24
into the main PCB.
a. Disconnect connector P24 (POWER1) from
the main PCB, and check the continuity
between terminals 1 and 2 of P24.
OK if ∞ ohms.
b. Disconnect connector P23 (PPM) from the
main PCB, and check the continuity between
terminals 1 and 2, 3 and 4 of P23.
OK if ∞ ohms.
c. Insert P23 and P24 into the main PCB, turn on
the power switch and then check LD1 (red) on
the power PCB.
OK if illuminated.
If LD1 is illuminated during the check in step 1
but it does not illuminate when P1 and P24
are connected, there is a malfunction of the
main PCB.
d. Check LD1 (orange) on the main PCB.
OK if illuminated.
2717B
2722B
a. Check that connector P19 (P-ENC) is inserted
into the main PCB and that the color matches.
b. Check the encoder input while referring to
"4-7. Input checking method".
a. Disconnect the main PCB connector P23
(PPM) and measure the resistance between
pins 1-2 and 3-4 of the cord connector.
OK if 2-3 ohms.
b. If step a. (above) is OK, there is a malfunction
of the main PCB.
2723B
KE-430F, BE-438F
Parts to be replaced
Power PCB assembly
Main PCB assembly
Pulse motor P assembly
Main PCB assembly
Pulse motor P assembly
Main PCB assembly