Maintenance; Routine And Periodic Maintenance - Lincoln Electric SQUARE WAVE IM687 Operator's Manual

D-1
SAFETY PRECAUTIONS
WARNING
ELECTRIC SHOCK can kill.
• Only qualified personnel should
perform this maintenance.
• Turn the input power OFF at the
disconnect switch or fuse box
before working on this
equipment.
• Do not touch electrically hot
parts.
WARNING
To avoid receiving a high frequency shock, keep the
TIG torch and cables in good condition.

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
following 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
cooling.
6. The fan motor has sealed ball bearings which
require no maintenance.
7. SPARK GAP ADJUSTMENT
The spark gap is set at the factory to a gap of
0.015 inches (0.4mm) See Figure C.1. This setting
is adequate for most applications. Where less high
frequency is desired, the setting can be reduced to
0.008 inches (0.2mm).

MAINTENANCE

Use extreme caution when working with circuit of
the high frequency. The high voltages developed
can be lethal. Turn the input power off using the
disconnect switch or fuse box before working
inside machine. This is particularly important when
working on the secondary circuit of the high volt-
age transformer (T3) because the output voltage is
dangerously high.
Refer to figure C.1. Note in highly dirty environments where there
is an abundance of conductive contaminants, use a low pressure
air stream or a firm piece of paper to clean the spark gap. Do not
disturb the factory setting.
To check the spark gap:
- Turn off input power as specified above.
- Remove the wraparound from the machine, the spark gap 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, 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 decals.
10. Verify that the machine and welding circuit is properly
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 C.2 below.
SQUARE WAVE TIG 175 PRO
WARNING
FIGURE C.1 SPARK GAP
.015 Spark Gap
RIGHT SIDE OF MACHINE
.30
Figure C.2
D-1