Lincoln Electric INVERTEC 270SX Service Manual page 28

INPUT BOARD RESISTANCE TEST (continued)
Picture is related to Invertec
AC input power
supply 400V +/- 15%
Fan
connector
Fuse F2
Auxiliary
Transformer
TEST PROCEDURE
1. Remove main input power to the INVERTEC
2. Perform the Discharge procedure
3. Visually check for burned or damaged components.
If any components are physically damaged the input board should be replaced
Using the Volt-Ohmmeter (diode test mode) check the Input Rectifier (see Table 1)
4.
5. Failure of the Input Rectifier is typically the result of another problem. If the Input Rectifier does not pass the tests
detailed in Table 1 perform the IGBT test on inverter board
6. Check the PTC1 for 100 ohms +/- 20%. If PTC1 doesn not pass the test may be a failure (short) on capacitors or
IGBT is present.
7. Check the fan resistence across the fan connector. For Invertec 270SX fan resistance should be 260 ohm +/-
20%, while for Invertec 400SX should be 370 ohms +/- 20%.
8. Check the fuse F1 for continuity. Typically if F1 is open a problem occurred on the fan or on the auxiliary
transformer primary winding.
®
270SX Input board. Invertec
W05X0855-1 on
W05X0855-2 on
®
Table 1. Input Bridge test table
Positive Probe (RED)
1 (AC)
2 (AC)
3 (AC)
4 (+)
4(+)
4(+)
5 (-)
5 (-)
5 (-)
1 (AC)
2 (AC)
3 (AC)
Page 28
®
400SX input board is the same but without the four black snap-in capacitors
3
5
2
4
1
®
INVERTEC 270SX
®
INVERTEC 400SX
270SX or 400SX.
Negative Probe (BLACK)
4 (+)
4(+)
4(+)
1 (AC)
2 (AC)
3 (AC)
1(AC)
2 (AC)
3 (AC)
5 (-)
5 (-)
5 (-)
PTC1 test points
(resistence leg and
solder place near
Input bridge B1
Value
0.3V - 0.7V
0.3V - 0.7V
0.3V - 0.7V
OPEN
OPEN
OPEN
0.3V - 0.7V
0.3V - 0.7V
0.3V - 0.7V
OPEN
OPEN
OPEN
the small relay)