Thermal Arc ULTIMA 150, Руководство по обслуживанию

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Manual 0-2503 23 SECTION 3: SERVICE TROUBLESHOOTING
Once the problem has been identified and corrected, dis-
connect the primary power and place the Primary Power
ON/OFF Switch to the OFF position. Reconnect 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.
3.13 A/V Display Status
Under non-welding conditions, the A/V numeric display
is 00.
A. Incorrect A/V Display
1. Faulty Pilot PC Board.
a. If PREVIEW of pilot current doesn't display set
point, check J6 Ribbon Cable Connector. If it is
okay, replace the Pilot PC Board.
B. No A/V Display
1. Faulty Logic PC Board
a. If there is no A/V display, replace the Logic
PC Board.
3.14 Static Test Procedures
A. Input Diode/Main Diode Bridge (D1) with
Inrush Circuit Test Procedure
NOTE
This test requires a digital volt meter with a diode
test scale.
1. Perform a visual inspection of Input Diode (D1)
Bridge Assembly. This is located under the Input
PC Board and can be accessed by removing the 7
connection screws.
Most failures are identified by a fracture in the
plastic case of the device. If there are no signs of
physical damage or failure then proceed with the
following test procedure:
2. Disconnect lead #7 from the negative terminal of
Input Diode (D1) Assembly.
A-01103
R S T
Wire 7
+
Wire 10
R2
G
D1
T R S
+
G R2
Figure 3-8 Input Diode Assembly
3. Set meter on diode test scale.
4. The Input Diode (D1) Assembly contains six stan-
dard diodes and a SCR used for the inrush cir-
cuit. The diodes are connected to form a three-
phase full wave circuit with three diodes
connected to the negative terminal and three con-
nected to the R-2 terminal.
Test each diode in the forward (R-2 to R, S, T) and
reverse (- to R, S, T) direction as shown in Figure
3-8. A properly functioning diode conducts in the
forward direction (plus to negative) and blocks in
the reverse direction (negative to plus).
5. If any Diode section does not check properly, re-
move Input PC Board per Section 4.05.
6. To check the SCR in the Input Diode (D1) Assem-
bly use the following procedure:
7. Remove the leads from terminals R-2, G, and posi-
tive (+).
8. Check for shorts between R-2 and the (+) termi-
nal.
9. Check the gate between G and (+) terminals for
resistance of approximately 50 ohms.
10. If the SCR does not check properly, replace the
Input Diode (D1) Assembly per Section 4.05.
11. If the Input Diode (D1) Assembly checks are cor-
rect, reconnect the lead removed.