Lincoln Electric COMMANDER 400 SVM133-B Service Manual page 152

F-98
SCR REMOVAL AND REPLACEMENT (continued)
11. Go to the procedure below that matches your
machine's cap screw.
THREAD IS ON YOUR CAP SCREWS
BEFORE PROCEEDING TO THE ASSEM-
BLY PROCEDURE. Two different designs of
leaf springs and housings have been used to
clamp the SCR to the rectifier. The two dif-
ferent designs can be identified by the size of
the leaf spring. One design uses a 1/2 inch
wide leaf spring, and the other uses a 5/8
inch wide spring.
require different assembly and clamping pro-
cedures. The assembly procedure will be dif-
ferent depending upon the thread on the cap
screws. A 1/4-28 thread requires a different
tightening procedure than a 1/4-20 thread.
PROCEDURE FOR THE 1/2 INCH
WIDE SPRING
1. Place a piece of sleeving around each cap
screw.
2. Insert cap screws through the leaf spring.
Orient the leaf spring so that its ends are
curved upward toward the cap screw heads.
See Figure F.45. Pressing on the cap screw
heads should produce a "rocking" motion of
the spring in its housing. If the spring does
NOT rock, it is installed upside down.
Remove the spring and turn it over. Check
for "rocking" motion. See Figure F.45.
3. Insert cap screws and leaf spring into the
plastic housing.
TROUBLESHOOTING & REPAIR
FIGURE F.45 – 1/2" WIDE LEAF SPRING
NOTE WHICH
The different designs
COMMANDER 400
4. Insert clamp assembly through heat sinks.
Install nuts. Tighten clamp nuts equally on
cap screws until finger tight.
F.46. Heat sinks may not be exactly as pic-
tured.)
5. Reinspect the SCR for proper seating.
FIGURE F.46 – CLAMP ASSEMBLY
F-98
(See Figure