Brother BES-116 Instruction Manual page 145

Symptom
X-axis or Y-axis home position de-
tection error occurs.
The thread breakage error frequently
occurs although thread is not broken.
The main shaft motor lock error oc-
curs.
ERROR A8 frequently occurs.
• Was the XY carriage moving?
If so, refer to the block diagram showing the cable connections and
check to see if connection from the X and Y area sensor to the main
PCB is proper.
• Was the XY motor rotating?
If so, check the XY carriage mechanism.
• If the XY motor is not rotating, refer to the cable connection block
diagram and check to see if connection from the XY motor to the main
PCB is proper.
• Enter the needle bar case test mode by pressing
the thread breakage pulley.
If the needle bar number icon is displayed reversely, lower the thread
breakage sensitivity value of the machine controller. (The standard
value is 0.)
• Check connection from the thread breakage sensor PCB to the head
PCB if the needle bar number icon is not displayed reversely.
• Replace the thread breakage sensor PCB with a new one.
• Enter the encoder signal mode and manually turn the main shaft pulley.
If it is abnormally heavy, the main shaft mechanism is faulty.
• Does the main shaft motor rotate at all when the error occurs?
If it does not rotate at all, check fuse F1 and F5 on the power supply
PCB in the control box. Refer to the block diagram showing the cable
connections and check to see if connection from the main shaft motor
to the main PCB is proper. Also check connection of connectors P15
and P16 of the main PCB and connectors P1 and P2 on the power
PCB in the box, and connection from connector P14 of the main PCB
to the 14v terminal of the power transformer.
• Manually turn the main shaft pulley in the encoder signal test mode
and check to see if the stop position signal and encoder signal are
proper.
If either of the signals does not change, refer to the block diagram
showing the cable connections and check to see if connection from the
encoder and stop position sensor to the main PCB is proper.
• In the encoder signal test mode, manually turn the main shaft pulley
and check to see that the stop position signal is correct.
If the signal does not change, refer to the cable connection block
diagram and check to see if connection from the stop position sensor
to the main PCB is proper.
BES-116AC
Chapter 10 Troubleshooting
Measures
STOP
and , turn
143