Procedure for the 1/2 Inch Wide Spring

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F-48

TROUBLESHOOTING & REPAIR

SCR REMOVAL AND REPLACEMENT (continued)

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FIGURE F.29 – 1/2” WIDE LEAF SPRING

11.Go to the procedure below that matches your machine’s cap screws. NOTE WHICH THREAD IS ON YOUR CAP SCREWS BEFORE PROCEEDING TO THE ASSEMBLY PROCEDURE. Two different designs of leaf springs and housings have been used to clamp the SCR to the rectifier. The two different 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. The different designs require different assembly and clamping procedures. The assem- bly procedure will be different depending upon the thread on the cap screws. A 1/4-28 thread requires a different tightening procedure than a 1/4-20 thread.

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.29. 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.29.

3.Insert cap screws and leaf spring into the plastic housing.

4.Insert clamp assembly through heat sinks. Install nuts. Tighten clamp nuts equally on cap screws until finger tight. (See Figure F.30. Heat sinks may not be exactly as pictured.)

5.Reinspect the SCR for proper seating.