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F-9

TROUBLESHOOTING & REPAIR

F-9

TROUBLESHOOTING GUIDE

 

 

Observe Safety Guidelines

 

 

 

detailed in the beginning of this manual.

 

 

 

 

 

 

 

 

PROBLEMS

 

POSSIBLE AREAS OF

 

RECOMMENDED

 

 

(SYMPTOMS)

 

MISADJUSTMENT(S)

 

COURSE OF ACTION

 

 

 

 

 

 

 

 

 

 

 

TIG MODE PROBLEMS

 

 

 

The arc "flutters" when TIG welding. 1.

The tungsten electrode may be

1.

Check the polarity switch for

 

 

 

 

too large in diameter for the cur-

 

proper operation and loose or

 

 

 

 

rent setting.

 

faulty lead connections. See

 

 

 

 

 

 

wiring diagram.

 

 

 

2. The tungsten tip may not be

 

 

 

 

 

 

"sharp" enough.

2.

Perform the SCR Bridge Test.

 

 

 

 

3. Check for loose or faulty connec-

 

3.

The gas shielding may be insuffi-

 

tions at the shunt. ( leads #221

 

 

 

cient. Increase the gas flow and

 

and #222 ).

 

 

 

 

or reduce the tungsten stickout

 

 

 

 

 

 

beyond the gas cup.

4.

Check components R3 and C4 in

 

 

 

 

 

the high voltage transformer pri-

 

4.

Check for contaminated gas or

 

mary circuit. Replace if neces-

 

 

 

leaks in the gas line, torch, or

 

sary. See wiring diagram.

 

 

 

 

connections.

 

 

 

 

 

 

 

5. The control board may be faulty.

 

5.

If a helium blend is used as a

 

Replace.

 

 

 

 

shielding gas then reduce the

 

 

 

 

 

 

percentage of helium.

 

 

 

The arc "pulsates" when AC TIG

1. Make sure the gas and proce-

1. Check the micro switch S2A on

welding.

dure are correct for the process

the polarity switch. It may be

 

being used.

stuck closed. See wiring dia-

 

 

gram.

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the test/repairs safely, con- tact the Lincoln Electric Service Department for electrical troubleshooting assistance before you proceed. Call 1-888-935-3877.

PRECISION TIG 185

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Lincoln Electric SVM169-A service manual Troubleshooting & Repair