Lincoln Electric 350, 550 manual GUN Tube Replacement, Trigger Assembly Replacement

D-3 MAINTENANCE D-3

GUN TUBE REPLACEMENT

•Replace if worn from use; for example, if gas diffuser threads are deforming.

1.Remove consumables per this section, Gas Diffuser Replacement.

2.Remove swivel assembly at rear of handle (ccw, right-hand threads), remove fume tubeʼs locking collar from handle, and remove left side of handle.

3.Use snap ring pliers to remove both spiders from the old gun tube. Use hammer and drift to remove the gun tube lock from the old gun tube.

4.Obtain a new replacement gun tube.

5.Install spiders and gun tube lock onto the new gun tube.

6.Install new gun tube to the gun end of the gun cable. Tighten gun tube to gun cable with 10 to 12 ft.-lbs. of torque.

7.Reassemble gun. Route the control leads inside of gun handle per this section, Trigger and Accessory Switch Lead Routing. Be careful not to pinch any leads between gun handle halves.

TRIGGER ASSEMBLY

REPLACEMENT

•There are no serviceable or maintainable parts inside of the trigger.

1.Remove swivel assembly at rear of handle (counter clockwise, right-hand threads), remove fume tubeʼs locking collar from handle, and remove left side of handle.

2.Slide trigger out of right handle half. Disconnect red and white leads from trigger. Use care to prevent damage to electrical leads and the terminals.

3.Connect red and white leads to the new trigger. Either lead may be connected to either trigger pin (non-polarized connections).

4.Slide new trigger into place and reassemble the gun. Be careful not to pinch any leads between gun handle halves.

GUN CABLE ASSEMBLY

REPLACEMENT

•In general, the 350 and 550 gun cables have no ser- viceable or maintainable parts. Here are the only types of cable service that may be performed without removing or replacing an entire gun cable:

•Replace both “o-rings” on the gunʼs power and gas connector (see Table A.1, Installation Section).

•Repair the gunʼs four #19 AWG control leads by splicing and soldering them back together, and then reinsulating them with heat-shrink tubing. See Figure A.3 Installation Section and Trigger Assembly Replacement for a description of the connections.

•Otherwise, a damaged gun cable should be replaced as follows:

1.Remove liner assembly per this section Liner

Assembly Cleaning or Replacement.

2.Remove gun tube assembly per this section Gun Tube Replacement. Do not remove spiders or gun tube lock.

3.Disconnect gun cableʼs red and white control leads from trigger assembly.

4.Disconnect gun cableʼs blue and black control leads from optional accessory switch (if so equipped).

5.Disassemble the Y connector halves as follows. See Figure A.2 and A.4 Installation Section as a guide:

•Disconnect the gunʼs Y connector from the vacuum source.

•Use the Oetiker tool to remove the gunʼs clamp from its vacuum hose.

•Slide the clamp and hose off of the Y con- nectorʼs inlet.

•Remove the 2 screws from the Y connectorʼs modular trigger terminal housing.

•Remove the 3 screws from the Y connector.

•Separate the Y connector halves.

•Remove the modular trigger terminal housing halves and separate them.

MAGNUM™ PRO 350 and 550 FUME GUNS