Diode Module Removal And Replacement - Lincoln Electric MULTI-WELD SVM151-A Service Manual

F-58
DIODE MODULE REMOVAL AND REPLACEMENT(CONTINUED)
3. Perform the Case Cover Removal proce-
dure.
4. Perform the Power Capacitor Discharge
procedure.
5. Carefully turn the machine onto its side.
6. Using the 3/8" wrench, remove the four
screws holding the tunnel assembly to the
machine base.
machine back upright.
7. With the slot head screw driver, carefully
raise the tunnel assembly unit about one
inch and block it with the piece of wood.
This will allow access to the bottom allen
head screw on the diode module. Peel
away the adhesive-backed rubber stripping
as necessary. Use care – the stripping
may tear.
8. Using the 7/16" wrench, remove the two
outer screws, lock washers, and flat wash-
ers holding the negative capacitor strap to
the diode module. Note fastener order for
reassembly.
9. Using the 3/16" allen head wrench, remove
the two screws, flat washers, and spring
washers holding the diode module to the
heat sink.
10. Using the 9/64" allen wrench, remove the
set screw from the center of the diode
module.
11. Remove the diode module from the heat
sink.
TROUBLESHOOTING & REPAIR
Then carefully turn the
MULTI-WELD 350
REPLACEMENT
Refer to Figure F.15.
CAUTION
The proper tightening sequence is required to
mount the diode module to the heat sink in
order to avoid warping the base plate. Apply
the proper torque to all fasteners.
1. Be sure the heat sink mounting surface is
clean, dry, and free of grease.
2. Apply a thin, even coat (.1 to .25mm or .004
to .010 in) of Penetrox A13 thermal joint
compound to the diode module base plate
only, under the plastic body of the module.
Do not apply compound to the area under
the mounting holes.
3. Press the module firmly against the heat
sink, aligning the mounting holes.
F-58