Troubleshooting and repair, Rheostat removal and replacement (continued) – Lincoln Electric BULLDOG SVM208-A User Manual

Page 84

FIGURE F.11 – RHEOSTAT REMOVAL

RHEOSTAT REMOVAL AND REPLACEMENT (continued)

PROCEDURE

1. Remove the spark plug wire.

2. With the 3/8” nut driver, remove the 4 sheet

metal screws that hold the top cover to the con-
trol box. Remove the top cover.

3. With the small slot head screw driver, loosen

the screw that holds the knob to the rheostat
shaft. The shaft has a flat for locating the knob
at reassembly.

4. With a 9/16” open or box end wrench, remove

the nut that holds the rheostat to the control
panel. Support the rheostat with your hand as
you turn the nut. There is a shake-proof wash-
er under the nut.

5. Pull the rheostat back out of the control panel

and lay it out on its wires to loosen the nuts that
hold them.

6. With the 5/16” open or box end wrench, remove

the brass nuts from the wire terminals. Support
the terminals as you turn the wrench to avoid
ripping the terminals from their foundations.
Note the wire locations for reassembly.

NOTE: The brass screws are double-nutted with a

shake-proof star washer under the screw
head.

7. To reinstall the rheostat, replace each of the

brass screws. Place a shake-proof star wash-
er under the head, insert the screw into the
rheostat and tighten down one nut. Replace
the appropriate wires and tighten down the
second nut. Again, support the terminals as
you turn the wrench to avoid ripping the termi-
nals from their foundations.

8. Reassemble the rheostat to the front of the

control panel. Line up the locating tab on the
rheostat with the slot on the control panel hole.

9. Reassemble the shake-proof star washer and

nut and tighten securely with the 9/16”
wrench.

10. Locate the flat spot on the shaft, line up the

knob locking screw, push the knob onto the
shaft and tighten the screw with the small slot
head screw driver.

11. Check the rheostat knob for proper rotation,

minimum to maximum.

12. Replace the top cover of the control box and

tighten the 4 sheet metal screws with the 5/16”
nut driver.

TROUBLESHOOTING AND REPAIR

F-36