Troubleshooting & repair – Lincoln Electric POWER WAVE SVM173-A User Manual
Page 133
TROUBLESHOOTING & REPAIR
F-87
F-87
POWER WAVE 455M/MSTT
SWITCH BOARD AND FILTER CAPACITOR
REMOVAL AND REPLACEMENT (CONTINUED)
7. Using the 7/16” wrench, remove leads
13/14 or 17/18 from the switch board.
8. Using the 7/16” wrench, remove leads
11/12 or 15/16 from the switch board.
9. Using the 7/16” wrench, remove leads
19C/D+ and 20C/D- from the switch board
capacitor connection bolts.
10. With the slot head screwdriver, remove the
two nylon mounting screws at the bottom of
the switch board. Note placement of the
shake-proof washers and fiber spacers.
11. Using the 3/16” allen wrench, carefully
remove the four cap screws that mount the
switch board to the heat sink.
12. Carefully remove the switch board from the
heat sink.
13. If the filter capacitor is to be removed, care-
fully slide it out of the mounting bracket.
REPLACEMENT PROCEDURE
1. If the filter capacitor is to be replaced, care-
fully slide the new capacitor into the mount-
ing bracket. Position the capacitor so the
correct polarity terminal is lined up with the
correct hole on the switch board.
2. All heat sink and IGBT mounting surfaces
must be clean.
3. Apply a thin coat of thermal compound
(Penetrox A13) 0.005 to 0.010 inches thick
to the mating surfaces. Do not apply
around mounting holes.
4. Apply a thin coat of Penetrox A13 to the
capacitor terminals. Be careful not to apply
compound to screw threads or threaded
area of terminals.
5. Mount the new switch board and tighten
the four cap head screws in the following
manner.
Tighten all until snug.
Tighten all from 24 to 28 in-lbs.
Tighten all from 40 to 48 in-lbs.
6. Make sure the capacitor is positioned cor-
rectly. Connect leads 19C/D+ and 20C/D-
to the correct terminals. Tighten to 55
in/lbs.
7. Position and mount the two nylon screws,
fiber spacers, and washers. Torque from 4
to 8 in-lbs.
8. Connect leads 11/12 or 15/16 to the correct
terminal.
9. Connect leads 13/14 or 17/18 to the correct
terminal.
10. Install the mylar insulating shield covering
leads 11/12 or 15/16. Replace the cable
tie.
11. Connect molex plug J40/J50 to the top of
the switch board.
12. Using the 5/16” nut driver, install the plastic
high voltage protective shield.
13. Install the case top and sides using the 3/8”
nut driver.