Thermal Dynamics Cutmaster 82, Service Manual

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cutmaster 82
SERVICE 5-18 Manual 0-4980
C. ARC VOLTS signals are low or not present
1. Defective Automation Interface PCB (PCB4)
a) Replace PCB4
5.12 Test Procedures
A. Main Contactor (W1) Test
1. Check continuity between:
L1 to T1
L2 to T2
L3 to T3
L4 to T4
The contacts should be open – no continuity.
L4
L3
L2
L1
T4
T3
T2
T1
Actuator Arm
Cover Screws
Art # A-08157_AB
Input
Side
CutMaster 52 & 82
W1 contactor wired for 1PH
Main Contactor
Jumpers
Actuator Button
2. Retest continuity between terminals while engag-
ing the contacts manually. This can be done by
pushing down on the recessed actuator button on
the top of W1 or pushing down on the actuator
arm on the side of W1.
L1 to T1
L2 to T2
L3 to T3
L4 to T4
The contacts should be closed – Continuity
3. Visually check W1 contact points. To take the
cover off, remove the two cover screws shown in
the previous illustration. Replace if contacts are
stuck together or show excessive arcing
B. Input Diode Module Test
1. Using an ohmmeter perform the tests in the
chart
Input Diode Module
Meter (+) Meter (-) Indication
AC1 MTH 2 Forward Bias
AC2 MTH 2 Forward Bias
AC3 MTH 2 Forward Bias
MTH 2 AC1 Reverse Bias
MTH 2 AC2 Reverse Bias
MTH 2 AC3 Reverse Bias
MTH 5 AC1 Forward Bias
MTH 5 AC2 Forward Bias
MTH 5 AC3 Forward Bias
AC1 MTH 5 Reverse Bias
AC2 MTH 5 Reverse Bias
AC3 MTH 5 Reverse Bias
2 . If the test reveals a failed component, replace
Main PCB and perform main contactor test – Sec-
tion 5.11A
C. Input Capacitor PCB Test
1. Using an ohmmeter check continuity between the
following points:
Input Capacitors
Meter + Meter - Indication
MTH 2 MTH 4 Charging
MTH 4 MTH 5 Open
MTH 6 MTH 5 Charging
Most meters will show a charging action. Initially a
low resistance will be shown and then the resistance
will start to increase. If the meter probes are reversed
the reading will decrease to zero, then start charging
in the opposite polarity.
2. If a short is found replace Capacitor PCB assem-
bly.
3. Check continuity between the following points
Input relays Indication
MTH 2 MTH 6 Open
MTH 4 MTH 6 Open
MTH 4 MTH 5 Open
4. If a short is found, replace Capacitor PCB assem-
bly