F-59
F-59
PRECISION TIG 375
TROUBLESHOOTING & REPAIR
8.
Go to procedure that matches 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 differ-
ent designs require different assembly and
clamping
procedures.
The assembly 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.
PROCEDURE FOR THE 1/2 INCH
WIDE SPRING
1.
Place a piece of sleeving around each bolt.
2.
Insert bolts thru the leaf spring. Orient the
leaf spring so that it's ends are curved
upward toward the bolt heads. See figure
F.21. Pressing on the bolt heads should pro-
duce 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.16.
Fig. F.16 - 1/2" Wide Leaf Spring
3.
Insert bolts and leaf spring into the plastic
housing.
4.
Insert clamp assembly thru heat sinks. Install
nuts. Tighten clamp nuts equally on bolts until
finger tight. (See Figure F.17. Heat sinks may
not be exactly as pictured.)
Fig. F.17 - Clamp Assembly.
5.
Re-inspect the SCR for proper seating.
SCR REMOVAL AND REPLACEMENT (CONTINUED)
SPRING CURVATURE
EXAGGERATED
1/2"
HOUSING
HEAT SINK
1/4-28 OR 1/4-20
CAP SCREW
SLEEVING
S.C.R.
HEAT SINK
PLAIN WASHER
HEX NUT
LEAF
SPRING