Hobart 750 manual Troubleshooting, Running slowly

4-4. Troubleshooting

	Trouble		Remedy
No pilot arc; difficulty in establishing an		Clean or replace worn consumables as necessary (see torch Owner’s Manual).
arc.
		Check for damaged torch or torch cable (see torch Owner’s Manual).
		Have Factory Authorized Service Agent check power switch S1, control relay CR1, CR5 and CR6, rectifi-
		er SR1 (and SR2 for single-phase models), safety control board PC1, power control boards PC2 and
		PC3, inductor L1, resistor R1, and check gas air system for leaks.
No cutting output; Power light off;		Place Power switch in On position.
Trouble lights off; Ready light off; fan mo-
tor FM does not run.
		Place line disconnect device in On position (see Section 2-9).
		Check line fuse(s) and replace if needed or reset circuit breakers (see Sections 2-7 and 2-9).
		Have Factory Authorized Service Agent check power switch S1, transformer T1, and fan motor.
No cutting output; Power light on; Ready		Be sure work clamp is connected.
light on; Trouble lights off; fan motor FM
running.
		Clean or replace worn consumables as necessary (see torch Owner’s Manual).
		Have Factory Authorized Service Agent check safety control board PC1, power control boards PC2 and
		PC3, and rectifier SR1 (and SR2 for single-phase models).
No cutting output; Power light on; Ready		Check position of input voltage jumper links (see Section 2-8).
light on; Trouble lights off; fan motor FM
running slowly.
		Check input power, and check for proper input connections (see Sections 2-7 and 2-9).
No control of output.		Have Factory Authorized Service Agent check safety control board PC1 and power control boards PC2
		and PC3.
No gas/air flow; Power light on; Ready		Have Factory Authorized Service Agent check for proper torch connections, and check safety control
light on; Trouble lights off; fan motor FM		board PC1. Check operation of gas valve GS1, and check gas/air system for leaks.
running.
Pressure Trouble light On; Ready light		Check for correct gas/air pressure adjustment (see Section 3-2).
off.
		Check for sufficient gas/air supply pressure (see Section 2-6).
		Check for dirty air filter/regulator and clean, if needed (see manufacturer’s instructions).
		Check air lines for leaks.
		Have Factory Authorized Service Agent check pressure switch S3 and safety control board PC1.
Cup Trouble light On; Ready light off.		Check torch shield cup (see Section 4-3). Reset power switch.
		Have Factory Authorized Service Agent check for proper torch connections, and check safety control
		board PC1.
Temperature Trouble light On; Ready		Main transformer or main rectifier overheating. Allow fan to run; the Trouble light goes out when the unit
light off.		has cooled.
		Have Factory Authorized Service Agent check safety control board PC1.

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