Thermal Arc ULTIMA 150, Service Manual, Page: 22 / 64

SECTION 3: SERVICE TROUBLESHOOTING 16 Manual 0-2503
2. Incorrect Voltage Selection
a. Check that the High-Low Voltage Selection
Plug is in the proper receptacle for the appli-
cation and that it is properly connected. Cor-
rect voltage selection, if required.
b. Check that all pins in J15, J17, J18, and J7 are
all properly seated.
High Voltage
Receptacle
Low Voltage
Receptacle
A-01098
pin 13
Voltage Plug
(J15)
(J18)
(J17)
Figure 3-3 High-Low Voltage Selection
3. Faulty Primary ON/OFF Switch
a. Measure AC input voltage at primary power
ON/OFF switch line and load terminals. Com-
pare top readings with bottom readings. Mea-
sure voltages on the required terminals per one
of the following:
• L1 and L2 for single-phase
• L1 and L2 and L3 for three-phase
If voltage is not present or low, disconnect the
primary power, place the Primary Power ON/
OFF Switch in the OFF position, then replace
Switch.
4. Faulty Fuse
a. Check the input voltage at Pin 13 on the High-
Low Voltage Selection Plug (J15) with respect
to L2. (Refer to Figure 3-3). This voltage should
be the same as the incoming voltage.
If voltage is not present, check the internal fuse.
If fuse needs to be replaced, disconnect the pri-
mary power, place the Primary ON/OFF
Switch in the OFF position and replace inter-
nal fuse (1FU).
5. Faulty Transformer
a. Check J7 connection at Transformer (located in
front of the Output PC Board) for proper con-
nection.
b. Measure the output voltages at J4 on the Trans-
former (at Logic PC Board) for the following:
Pins Voltage Level
1 to 2 18-25 VAC
2 to 3 18-25 VAC
If voltage is not present, disconnect the primary
power, place the Primary Power ON/OFF
Switch in the OFF position and replace Trans-
former.
6. Defective Logic PC Board
a. Check Logic PC Board at TP3 to TP1 (ground).
Voltage should be 18-25 VDC.
If voltage is not present, disconnect the primary
power, place the Primary Power ON/OFF
Switch in the OFF position and replace the
Logic PC Board.
Once the problem has been identified and corrected, make
sure the primary power is disconnect and the Primary
Power ON/OFF Switch is in the OFF position then re-
connect J3 to Logic PC Board to enable DC output circuit.
Repeat steps in Section 3.06, Basic Functions to ensure
the system is fully functional.
3.08 Temperature Indicator Light
Status
Under normal operating conditions, the TEMP Indicator
light is green.
Complete the following before attempting service:
• Disconnect the primary power and place the Pri-
mary ON/OFF Switch in the OFF position.
• Unplug J3 from Logic PC Board to disable DC out-
put circuit.
• Connect the primary power and place the Primary
Power ON/OFF Switch in the ON position.
A. TEMP light not on or TEMP light red.
1. Obstructed air flow through unit.
a. Check for air obstruction within unit. Blow out
radiator fins if necessary.