14 • Service Manual — COATS Models 950/950 ProRacer/1025/1050/1055
Direct Drive
Does the wheel rotate clockwise
when the forward contactor is
engaged
Reverse any two power leads
at power source and re-test.
Does the brake contactor
remain closed?
Turn the power switch OFF &
unplug the machine. Disconnect
the white/blue wire from A1 on the
brake contactor. Use an Ohmme-
ter to check from A2 on the brake
contactor to terminal A2 on the
forward contactor. Connect the
white/blue wire.
Has one of the 1A breakers on
the rear of the machine tripped?
Disconnect the wire from terminal A2
of the brake contactor & check the coil
resistance from A1 - A2. Is the
resistance of the coil between 3 & 5
Ohms (5 to 7 on new contactors)?
Is there 27VAC between A2 on
the brake contactor & terminal 4
on the connector on the right
side of the PCB?
Does the brake contac-
tor ever close?
No
Yes
No
Replace the optical encoder.
See Replace Procedure.
No
Yes
No
Yes
Replace the PCB. See
Replace Procedure.
Disconnect the wire from A2 on
the brake contactor. Use an
Ohmmeter to check continuity
from A1 on the brake contactor to
terminal 5 on the connector on
the right side of the PCB.
Connect the wire to terminal A2
on the contactor.
Replace the PCB. See
Replace Procedure.
No
Yes
No
Yes
Less Than 1 Ohm
Repair or replace
defective wire or
connection.
More Than
1 Ohm
More Than
1 Ohm
Less
Than 1
Ohm
Yes
Replace the contactor. See
Replace Procedure.
Manually close the brake
contactor. Is there a 230VAC
between terminals 3 to 5, 5 to
13, & 13 to 3 ?
Is this a Model 950?
Replace the contactor. See
Replace Procedure.
Yes
No
No
Yes
CONTINUED ON
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Check the connections from
the contactor to the motor.
Repair or replace the defec-
tive wire or connections.
Bad
Good
Replace the drive motor. See
Replace Procedure.
Replace the optical encoder.
See Replace Procedure.
Does the forward
contactor ever open?
No
Yes
Balancer Does Not Brake (Contactor Model)
Manually closing the contactor to
check voltage may cause the wheel to
spin at high speeds. To avoid this from
happening disconnect the wires going
from the contactor to the motor.
CAUTION