20 • Service Manual — COATS Models 950/950 ProRacer/1025/1050/1055
Direct Drive
Replacement Procedures Section
for Models 950,1025, 1050, &
1055 Balancers
The procedures in this section will aid in replacing
major sub-assemblies of the balancer.
Do not disassemble, adjust or replace any part before
performing the PRELIMINARY INSPECTION and
FUNCTIONAL CHECK PROCEDURES. These proce-
dures, along with the troubleshooting flow charts, will
isolate the necessary adjustment or replacement.
Perform checks in the order listed and exactly as spec-
ified.
Refer to the illustrated parts breakdowns and parts
lists in the back of the manual for parts identification.
Standard commercial fittings and fasteners are used
throughout and should be obtained locally.
Check all interconnecting wiring and connectors
when an electrical malfunction is indicated. Check all
fittings and fasteners when a mechanical malfunction is
indicated.
Front Panel/Printed Circuit Board Assembly
Important: Never replace the printed circuit
board without first checking the contactor
coil resistance whenever any of the follow-
ing symptoms occur. Shorted contactor
coils will result in failure of the new printed
circuit board.
1.
Displays do not light.
2.
Drive motor does not start.
3.
Drive motor does not stop.
Contactor Coil Resistance Measurement
1
. Unplug the balancer.
2.
Disconnect the plug from the right side of printed
circuit board assembly.
3.
Set ohmmeter to lowest scale.
4.
Measure the resistance from terminals A1 to A2
on both the start and brake contactors.
5.
Resistance should be 3 to 5 ohms (5 to 7 ohms on
newer contactors with metal plate on the bottom), if
not, replace the contactor.
New Repair Procedure:
The models 950,1025,1050,
and 1055 are different from other COATS balancers in
that the Front Panel/ Printed Board assembly has been
designed so that the PCB Assembly and the Touch
Panel/ Aluminum Back Panel can be replaced sepa-
rately. Refer to the Trouble Shooting section for diag-
nostic instructions for isolating the defective assembly.
Front Panel/Printed Circuit Board Assembly
Replacement
1.
Unplug the balancer.
2.
Check contactor coil resistances, see the proce-
dure on page 24.
3.
Remove the four (4) 6-32 acorn nuts on the back of
the pod.
4.
Disconnect the plugs on the PCB Assembly.
5.
Remove the Front Panel/Printed Circuit Board
Assembly.
6.
Connect the plugs to the new PCB Assembly.
7.
Line up the four (4) 6-32 studs on the back of the
Touch Panel/Aluminum Back Panel with the four (4)
holes in the pod and install.
8.
Install the four (4) 6-32 acorn nuts.
9.
Plug in the balancer.
10.
Perform the 950/1050 Balancer Test Procedure.
11
. Perform the FUNCTIONAL CHECKS.
Touch Panel/Aluminum Back Panel And PCB
Assembly
1.
Unplug the balancer.
2.
If the PCB is being replaced, check contactor coil
resistances, see the procedure on page 24.
3.
Remove Front Panel/PCB Assembly from the pod.
4.
Remove the eight (8) screws holding the PCB
Assembly to the Touch Panel/Aluminum Back Panel.
5.
Disconnect the plug going to the PCB Assembly.
6.
Replace the defective Touch Panel/Aluminum Back
Panel or PCB Assembly and connect the plug from the
Touch Panel/Aluminum Back Panel to the PCB
Assembly.
Note: Make sure there are no twists or kinks
in the cable.
7.
Install the eight (8) screws holding the PCB assem-
bly to the Touch Panel/Aluminum Back Panel.
8.
Install Front Panel/PCB Assembly to the pod.
9.
Plug in the balancer
10.
Perform the FUNCTIONAL CHECKS.
