Lincoln Electric IDEALARC DC-1000 Service Manual page 69

F-35
3. Remove the red insulating paint from heat sink
test points. See Figure F.13.
NOTE: DO NOT DISASSEMBLE THE HEAT
SINKS.
4. Using an analog ohmmeter, test the resistance
from anode to cathode of SCR 1. Reverse the
meter leads and check from cathode to anode
of SCR 1. (R x 1000 SCALE).
a. If a low resistance is indicated in either
direction, disconnect the snubber circuit
(See Wiring Diagram) and retest SCR 1. If
a low resistance is still indicated, SCR 1 is
faulty - Replace. If a very high or infinite
resistance is indicated without the snubber
circuit, then replace the snubber circuit,
See Figure F.14.
TROUBLESHOOTING AND REPAIR
STATIC SCR TEST (continued)
FIGURE F.13 – SCR HEAT SIN ASSEMBLY TEST POINTS
IDEALARC ® DC-1000
F-35