4Chuck Adapter (2): Unscrew chuck adapter counter clockwise from cable clamp adapter. Important that chuck adapter is tight on cable clamp adapter to form a tight connection. An effective way of removing the adapter is to insert a round rod through two of the chuck eject holes.

Replace chuck adapter if inside surface or threads are pitted or damaged.

5Front Cover Nuts (1): The front cover is held on with two nuts. Use a 3/4 inch wrench to remove them. Inspect the plastic bearing (4) for damage or excessive wear.

6Front Cover (5): If gun is equipped with a plunge dampener it is located in the front cover. Inspect front cover for cracks and replace if cracked. The front cover prevents dirt from entering the internal mechanism and maintains alignment of internal components.

7Plunge Dampener (7): The dampener is inside the front cover. It pulls straight out and pushes straight back in. When the plunge dampener is activated by a finger it should offer continuous resistance over the entire range of travel. The plunger should then return, by itself, to full extension. If this is not the case the dampener needs to be replaced.

8Cable Clamp Adapter (8): Remove two #10−32 x 5/8 socket head cap screws (6) from cable clamp adapter. The cable clamp adapter will separate from the lifting rod. Maneuver the cable clamp adapter forward between the leg inserts. Remove the #8−32 x 1/2 cap screw (11) from the back of the cable clamp adapter (8).

Inspect threads on cable clamp adapter. If threads are damage re- place cable clamp adapter. This item transfers all the weld current. If there is damage to the threads, arcing will continue and poten- tially fuse all the components together.

9Lifting Mechanism: The lifting mechanism consists of the lifting rod (12), main spring (13), lift release (14), moveable core (15−20) and core return spring (21). To disassemble, press the lift release ring tight against the moveable core and pull the lifting rod out of the assembly. All components listed above, will come apart.

10Lifting Rod (12): Inspect lifting rod for wear or damage. The brass inserts should show no signs of loosening. The steel shaft should not have any nicks on it. Run a finger over the shaft. If you can feel grooves from the lifting bearing then the lifting rod is worn out. Typically the lifting rod and lift bearing should be replaced as a set. When reassembling, the shaft should have a light film of grease (a lithium based grease) applied.

11Disassembly of Moveable Core (15 - 20): Remove snap ring (20) from shaft (18) of core assembly. The snap ring acts as a spring seat and is important to maintain proper spring tension. Where the core assembles into the bearing housing is another retaining ring (19). This retaining ring can be removed with a small flat bladed screw driver. After removing the second retaining ring the bearing housing (15) will separate from the core shaft. The lift bearing (16) and the lift bearing spring (17) can now be removed.

When reassembling the lift bearing cage must oriented toward the lift bearing spring. Put a light film of grease (such as a lithium based grease) over the lift bearing and the lift bearing spring.

12Handle Covers (35): Remove 3 flat head screws (36 - 37) that retain the handle cover. Inspect handle cover for breakage.

13Weld Cable (40): The weld cable can lift out of the gun body. Be careful unthreading the internal weld cable (9) from inside the body. The internal and external weld cables can be unscrewed from the weld cable anchor plate (32). Note the orientation of the weld cable anchor plate. The radius corner goes toward the top of the body.

Inspect the internal weld cable for frayed or broken wires. If starting to fray, the internal cable should be replaced.

Inspect weld cable for fraying. Also inspect strain relief (38) for tears. Inspect cable jacketing for breaks, cuts or tears. If cable shows signs of damage or wear it should be replaced. In addition, inspect the weld−lok connector (39). If pitted or damaged, replace. Inspect weld cable to camlok joint to ensure there is no fraying of the weld cable.

14Control Cable (42) (if desired): The control cable is removed by cutting the wires by the splice connectors. Inspect the control cable for damage. This includes the strain relief (41) and the insulating jacketing. If damaged, replace the control cable.

When reinstalling the control cable, there are typically two different color schemes.

Scheme one: Black and White wires connect to the trigger - Blue and Brown Wiresconnect to the coil

Scheme two: Black and White wires connect to the trigger - Red and Green wires connect to the coil.

Make sure all crimp connections are tight and there is no opportuni- ty for electrical shorting.

15Trigger Switch (31): The trigger switch is a screw in style. Grabbing it can be difficult. A 1/2” collet is the ideal removal tool. Use an ohm meter to check trigger functionality.

16Rear Cap (29): Unscrew and remove. The rear cap prevents dirt and other contaminates from entering into the gun mechanism.

.Do not use rear of gun as a hammer to check quality of stud weld for this will damage the rear cap.

17Adjustable Core (28): Loosen nylon tipped set screw (27) in rear coil yoke which holds the adjustable core. Completely unscrew and remove adjustable core.

18Rear Coil Yoke (26): Loosen the nylon tipped set screw retaining the rear coil yoke. To perform this the hex key will have to go into the opening on an angle to reach the set screw. Once the retaining screw is loosened use a large wrench to unscrew the rear coil yoke.

19Coil (25): Coil wires (black and red or green and red inside the gun handle) must be cut prior to coil removal. Cut wires inside the handle. After coil wires are free, the coil can be pulled straight out

the rear of the gun. Coil condition - check to make sure there is no

varnish odor (a sign of overheating), heavy discoloration (another sign of overheating) and verify coil resistance at 19 ohms +/− 1 ohm.

20Front Coil Yoke (24): In front of the coil is the front coil yoke. This is a tight fit and may be difficult to remove. The front coil yoke contains a plastic bearing (4). This bearing should be inspected for wear or damage and replaced if necessary. During reassembly, make sure the bearing flange is seated in the counterbore on the front coil yoke. When putting the front coil yoke back into the coil can, make sure the bearing flange is facing rear of gun.

Tools Needed:

3/4 in

OM-216 244 Page 29

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Miller Electric 625 manual Tools Needed OM-216 244