Lincoln Electric IM467-B manual TIG Welding

E-4 E-4

TROUBLESHOOTING

TROUBLESHOOTING GUIDE

Observe Safety Guidelines detailed throughout this manual.

TIG WELDING (Continued)

SYMPTOM		CAUSE AND REMEDY
Machine has gas flow and high frequency but no	1.	Turn High Frequency Switch OFF. Look at the two LED’s in
open circuit voltage when the Arc Start Switch		the upper left corner of the Power PC board. They should
or Amptrol is pressed.		glow when the Arc Start Switch is pressed.
		If the LED’s do glow, leads 232A and 233A may be reversed
		on the primary of control transformer T5 in control box. Turn
		the machine off. Reverse the leads. Turn back on and check
		for open circuit voltage. If this does not fix the problem,
		restore wires 232A and 233A to their original positions.
		If the LED’s do not glow, the Power PC board may be defec-
		tive. Replace. If the problem still exists, the Control PC board
		may be defective. Replace.
Difficulty in getting tungsten to “light off”.	1.	Current Control switch is in REMOTE but machine is being
		used with an Arc Start Switch and no Amptrol. Set switch to
		LOCAL.
	2.	Start switch is ON, and Start Current is set too low for tung-
		sten size. Either turn Start switch OFF, or increase Start
		Current to proper level for tungsten size.
	3.	Current control is set too low. Amptrol is not being pressed
		far enough for the tungsten size being used. Try in LOCAL
		Current Control at a higher current setting. SEE NOTE
		BELOW.
	4.	Contaminated tungsten. If tungsten becomes contaminated
		with foreign materials, grind off end of tungsten to expose
		fresh electrode. Grind to a point for DC work and leave an
		end for AC work.
	5.	Incorrect tungsten type. Pure or zirconiated is recommended
		for AC welding; thoriated is required for DC welding.
	6.	No shielding gas (or not enough). Adjust gas flow for 10 to
		30 CFH (4.7 to 14.1 l/min) for most applications.
Machine welds only at minimum output when	1.	Current Control switch is in REMOTE but machine is being
the Current Control switch is in the REMOTE		used with an Arc Start Switch and no Amptrol. Set switch to
position.		LOCAL.
	2.	Use LOCAL Current Control. If problem goes away, Amptrol
		may be defective. Replace or repair Amptrol.
	3.	Current Control switch may be defective. Replace.
	4.	Can machine be preset for currents from 2 to 400 amps? If
		not, see “Cannot preset a current” in General
		Troubleshooting section.
Arc goes out soon after it is lit.	1.	Current Control is set too low, or Amptrol is not being
		pressed far enough for the tungsten size being used. SEE
		NOTE BELOW.
	2.	In AC, use Continuous High Frequency.

NOTE: STARTING DIFFICULTIES MAY OFTEN BE DUE TO NOT PRESSING THE AMPTROL FAR ENOUGH. WHEN THE AMPTROL IS JUST “CRACKED”, THE MINIMUM CURRENT (2 AMPS) IS PRODUCED. PRESSING THE AMPTROL MORE AT THE START OF THE WELD WILL OFTEN SOLVE STARTING PROBLEMS. Refer to page 23 for proper use of amptrols.

SQUARE WAVE TIG 355