Lincoln Electric COMMANDER 400 SVM133-B Service Manual page 155

F-101
SCR REMOVAL AND REPLACEMENT (continued)
CLAMPING PROCEDURE
FOR 1/4-28 CAP SCREWS
NOTE: This procedure can only be used with
1/4-28 cap screws.
Do not use cap screws with any other type thread
or new SCR will be damaged.
Do not over tighten cap screws. The leaf spring
will apply the required clamping force to the SCR.
1. Do not turn the nuts. While holding the nuts
stationary, turn the cap screws only with the
following procedure.
2. Tighten first cap screw 1/4 turn.
3. Tighten second cap screw 1/2 turn.
4. Tighten first cap screw 1/2 turn.
5. Tighten second cap screw 1/2 turn.
6. Tighten first cap screw 1/2 turn.
7. Tighten second cap screw 1/4 turn. STOP.
8. Assembly now has the proper clamping force.
9. Perform the Active SCR Test.
AFTER REPLACING THE SCRs
Follow the steps in the SCR/Diode Rectifier
Bridge Removal and Replacement procedure
to reassemble the machine.
TROUBLESHOOTING & REPAIR
COMMANDER 400
CLAMPING PROCEDURE
FOR 1/4-20 CAP SCREWS
NOTE: This procedure can only be used with
1/4-20 cap screws.
Do not use cap screws with any other type thread
or new SCR will be damaged.
Do not over tighten cap screws. The leaf spring
will apply the required clamping force to the SCR.
1. Do not turn the nuts. While holding the nuts
stationary, turn the cap screws only with the
following procedure.
2. Tighten first cap screw 1/4 turn.
3. Tighten second cap screw 1/2 turn.
4. Tighten first cap screw 1/2 turn.
5. Tighten second cap screw 1/4 turn.
6. Tighten first cap screw 1/8 turn.
7. Tighten second cap screw 1/8 turn. STOP.
8. Assembly now has the proper clamping force.
9. Perform the Active SCR Test.
F-101