E-5

 

TROUBLESHOOTING

E-5

 

 

 

 

 

 

Observe all Safety Guidelines detailed throughout this manual

 

 

 

 

 

 

PROBLEMS

POSSIBLE AREAS OF

RECOMMENDED

 

 

(SYMPTOMS)

MISADJUSTMENTS

COURSE OF ACTION

 

 

 

 

 

 

PRESET & OUTPUT CONTROL PROBLEMS

Meter does not display preset

1. Faulty potentiometer R1 or its con-

 

 

 

nection

 

 

2.

Bad connection at P9 of Control

 

 

 

PC board

 

 

3.

Faulty Advanced Control PC board

 

 

 

( if present ) or its connection to

 

 

 

the main Control PC board

 

 

4.

Missing plug P3 on Control board

 

 

 

or bad connection at P3 when an

 

 

 

Advanced Control PC board is not

 

 

 

present

 

 

 

High output current in both DC & AC

1.

Bad connection at P6 of Control

polarities regardless of preset

 

PC board

 

 

2.

Bad shunt connection

 

 

3.

Faulty Control PC board

 

 

4.

Faulty SCR bridge

 

 

 

High output current in DC polarity

1.

Shorted free wheeling diode D1

regardless of preset, o.k. in AC polar-

 

 

ity

 

 

 

 

 

 

In 2-step Tig, output stays on for

1.

Bad 2/4 step switch or its connec-

more than downslope time after trig-

 

tion

ger open (machine with Advanced

 

 

Control panel only)

2.

Bad connection at P1 of Advanced

 

 

 

Control PC board

 

 

 

Output stays on after releasing

1.

Downslope is not set at min.

hand/foot

Amptrol (machine with

 

 

Advanced

Control panel only)

2.

Bad Downslope potentiometer

 

 

 

R12 or its connection

 

 

 

 

 

 

 

 

If all recommended possible areas of misadjustment have been checked and the problem persists, Contact your local Lincoln Authorized Field Service Facility.

CAUTION

If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.

PRECISION TIG 375

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Lincoln Electric IM703-A manual Preset & Output Control Problems