Miller Electric 333, 271, 383, 293, 273 manual Troubleshooting, Replace Z1 if necessary

5-4. Troubleshooting

Trouble	Remedy
No weld output; wire does not feed.	Be sure line disconnect switch is On (see Section 3-8).
	Replace building line fuse or reset circuit breaker if open.
	Reset circuit breaker CB1 (see Section 5-2).
	Secure gun trigger connections.
	Check continuity of power switch S1 and replace if necessary.
	Check main transformer T1 for signs of windig failure. Check continuity across windings and check for
	proper connections. Check secondary voltages. Replace T1 if necessary.
	Check continuity of thermostats TP1 and TP2. Replace TP1 and TP2 if necessary.
	Check main control board PC1 and connections and replace if necessary.
No weld output; wire feeds.	Connect work clamp to get good metal to metal contact.
	Replace contact tip (see gun Owner’s Manual).
	An overload condition occurred (see Section 5-3)
	Check diodes in main rectifier SR1, and replace if necessary.
	Check stabilizer Z1 for signs of winding failure. Check continuity across windings and check connections.
	Replace Z1 if necessary.
	Check main transformer T1 for signs of winding failure. Check continuity across windings and check con-
	nections. Check secondary voltages. Replace T1 if necessary.
	Check voltage switch(s). Replace if necessary.
Low weld output.	Connect unit to proper input voltage or check for low line voltage (see Section 3-6).
	Check input voltage jumper links and correct position if necessary (see Section 3-6).
	Check main rectifier SR1, and replace if necessary.
	Check voltage switch(s). Replace if necessary.
Low, high, or erratic wire speed.	Readjust front panel settings (see Section 4-1).
	Change to correct size drive rolls.
	Readjust drive roll pressure (see Section 3-11).
	Replace inlet guide, contact tip, and/or liner if necessary.
	Check position of input jumper links (see Section 3-6).
	Check Wire Speed control R1, and replace if necessary.
	Check diodes in main rectifier SR1, and replace if necessary.
	Check main control boarf PC1 and connections and replace if necessary.
No wire feed.	Reset circuit breaker CB1 (see Section 5-2).
	Rotate Wire Speed control R1 to higher setting (see Section 4-1).
	Clear obstruction in gun contact tip or liner (see gun Owner’s Manual).

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