Lincoln Electric PRECISION TIG SVM186-A Service Manual page 32

D-2
SAFETY PRECAUTIONS
WARNING
ELECTRIC SHOCK can kill.
• Only qualified personnel should per-
form this maintenance.
• Turn the input power OFF at the dis-
connect switch or fuse box before
working on this equipment.
• Do not touch electrically hot parts.
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WARNING
To avoid receiving a high frequency shock, keep
the TIG torch and cables in good condition.
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ROUTINE AND PERIODIC MAINTENANCE
1. Disconnect power supply lines to machine before
performing periodic maintenance.
2. Periodically clean the inside of the machine with a
low pressure air system. Be sure to clean the fol-
lowing components thoroughly.
• Main Transformer
• Electrode/Gas Output Receptacle
• Polarity Switch
• Rectifier Assembly
• Arc Starter/Spark Gap Assembly
• PC Boards
• Fan Blades
3. Inspect welder output and control cables for fraying,
cuts, and bare spots.
4. Keep TIG torch and cables in good condition.
5. Clean air louvers to ensure proper air flow and cool-
ing.
6. The fan motor has sealed ball bearings which
require no maintenance.
7. SPARK GAP ADJUSTMENT
The spark gap .020(.5mm) is set at the factory to a
gap of 0.015 inches (0.4mm) See Figure D.1. This
setting is adequate for most applications. Where less
high frequency is desired, the setting can be reduced
to 0.015 inches (0.4mm).
MAINTENANCE
Use extreme caution when working with a high fre-
quency circuit. The high voltages developed can
be lethal. Turn the input power off using the dis-
connect switch or fuse box before working inside
machine. This is particularly important when work-
ing on the secondary circuit of the high voltage
transformer (T3) because the output voltage is
dangerously high.
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Refer to figure D.1. Note in highly dirty environments
where there is an abundance of conductive contami-
nant's, use a low pressure air stream or a firm piece of
paper to clean the spark gap. Do not disturb the facto-
ry setting.
To check the spark gap:
- Turn off input power as specified above.
- Remove the right side panel from the
machine, the spark gap box is located on the
lower right side.
- Check the spark gap with a feeler gauge.
If adjustment is needed:
- Adjust the gap by loosening the allen head
screw in one of the aluminum blocks, near
the front of the unit and tighten the screw in
the new position.
If the gap is correct:
- Replace the wraparound.
8. Inspect gas hose and inlet fitting for cracks or leaks.
9. Replace any unreadable labels or decal's.
10. Verify that the machine and welding circuit is prop-
erly grounded.
FAN MOTOR OR FAN BLADE REPLACEMENT
When installing a new fan blade or fan motor be sure
to maintain proper shaft spacing per Figure D.2 below.
PRECISION TIG® 225
WARNING
FIGURE D.1 SPARK GAP
.020 Spark Gap .020 Spark Gap
.30ł
FIGURE D.2
D-2