Lincoln Electric LN-25 PRO DUAL POWER Service Manual page 69

F-19
PRESET (DISPLAY) PCB TEST (continued)
|
J9
+
PROCEDURE
5. Check for the following voltages from the chart
below.
Description
Supply power for
Preset (Display) PCB
Supply power for current transducer
Supply power to the current
transducer
Feedback from the current transducer
6. If the feedback voltage from the current trans-
ducer is incorrect or zero while under load, the
current transducer is faulty.
7. If any of the voltages on J8 or the voltage on
J10 (Pin 3) are zero, check for the supply volt-
age from the control PCB described in the chart
below.
Description
Supply power for
Preset (Display) PCB
8. If any of the voltages in the above chart are
incorrect or zero the control board may be
faulty.
TROUBLESHOOTING AND REPAIR
FIGURE F.6 – PRESET (DISPLAY) PCB
Positive Lead (RED) Negative Lead (BLACK)
J8 (Pin 1)
J8 (Pin 2)
J8 (Pin 3)
J8 (Pin 4)
J8 (Pin 9)
J10 (Pin 1) While welding
Positive Lead (RED) Negative Lead (BLACK)
J1 (Pin 1)
J1 (Pin 2)
J6 (Pin 8)
LN-25™ PRO DUAL POWER
|
J12
+
J8
16 15
8 7
J8 (Pin 10)
J8 (Pin 10)
J8 (Pin 10)
J8 (Pin 10)
J8 (Pin 10)
J10 (Pin 2) While welding 0.8VDC per 100 Amps
J1 (Pin 10)
J1 (Pin 10)
J1 (Pin 10)
F-19
J10
14 13 12 11 10 9
6 5 4 3 2 1
Expected Value
+15VDC
+5VDC
-15VDC
-15VDC
+15VDC
Expected Value
+15VDC
+5VDC
-15VDC