Under-Cooler Service - Lincoln Electric PRECISION TIG 375 IM909 Operator's Manual

Lincoln electric welder user manual

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Table Of Contents

Table of Contents

D-2

SERVICE PROCEDURES

Operation of the Precision TIG should be trouble-free

for the life of the machine. Should a malfunction occur,

however, the following procedures will be useful to

trained service personnel with experience in repairing

arc welding equipment:

COMPONENT ACCESS

The following components are accessible for routine

set up and periodic service without requiring removal

of the case sides or roof:

• Input Reconnect Panel (refer Section A) is located

behind a removable panel on the rear of the left case

side. Remove the two screws (with a screwdriver or

a 3/8"/ 9.5mm hex driver) on the bottom corners of

this panel to remove it.

• Control Box components and PC Boards (refer

Section B-6) are located behind the front control

panel. Remove the two screws (with a screwdriver or

a 3/8"/ 9.5mm hex driver) on the top corners of this

panel to swing it down.

• Hi-Freq. Spark Gap assembly (refer Spark Gap

Adjustment) is located behind a removable panel on

the rear of the right case side, under the torch box.

Remove the screw (with a screwdriver or a 3/8"/

9.5mm hex driver) on the bottom center of this panel

to remove it.

SPARK GAP ADJUSTMENT

The spark gap is set at the factory to a gap of 0.015

inches (0.4 mm) See Figure C.1. This setting is ade-

quate for most applications. Where less high frequen-

cy is desired, the setting can be reduced to 0.008 inch-

es (0.2 mm).

WARNING

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 the machine. This is particularly important

when working on the secondary circuit of the high

voltage transformer (T3) because the output volt-

age is dangerously high.

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MAINTENANCE

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

out the spark gap. Do not disturb the factory gap set-

ting.

To check the spark gap:

1. Turn the input power off per above.

2. Remove the access panel on the right case side

(See Component Access).

3. Check the spark gap spacing with a feeler gauge.

If adjustment is required:

1. Adjust the gap by loosening the Allen head screw

on one of the aluminum blocks, reset the gap and

tighten the screw in the new position.

If spark gap is correct:

1. Reinstall the access panel on the right case side.