Lincoln Electric 7FH manual Procedure for Replacing PC Boards Electric Shock can kill

Procedure for Replacing PC Boards

WARNING

ELECTRIC SHOCK can kill.

•Have a qualified individual install and service this equipment.

•Turn the power source input power off at the disconnect switch before working on this equipment.

•Do not touch electrically hot parts.

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Before replacing a PC board which is suspected of being defective, visually inspect the PC board in question for any electrical or mechanical damage to any of its components and conductors on the back of the board.

a. If there is no visible damage to the PC board, install a new one and see if this remedies the problem. If the problem is remedied, reinstall the old PC board to see if the problem still exists. If it does no longer exist with old PC board:

1.Check the PC board harness connector pins for corrosion, contamination, or looseness.

2.Check leads in the plug harness for loose or intermittent connection.

b.If PC board is visibly damaged electrically, before possibly subjecting the new PC board to the same cause of failure, check for possible shorts, opens, or grounds caused by:

1.Frayed or pinched lead insulation.

2.Poor lead termination, such as a poor contact or a short to adjacent connection or surface.

3.Shorted or open motor leads, or other external leads.

4.Foreign matter or interference behind the PC boards.

c.If PC board is visibly damaged mechanically, inspect for cause, then remedy before installing a replacement PC board.

If there is damage to the PC board or if replacing PC board corrects problem, return it to the local Lincoln Electric Field Service Shop.

Gun Cable Connector Requirements to Permit Proper Connection to Wire Feed Units

Connector for 1/16 - 5/64” (1.6 - 2.0 mm) Wire

Connector for .023 - .052” (19.0 / 18.9 mm) Wire (For all other dimensions, See Diagram above).

NOTE: Connector part with .749/.747 (19.0/18,9 mm) diameter should be made from brass if it is to be part of the welding current carrying circuit.

	“A” Diameter Hole
	to be Concentric to
Wire Size	.749/.747 (19.0/18.9 mm)
in. (mm)	Diameter Within .008 (.20) F.I.M.
.068- 5/64	.125 [1/8 (3.2 mm) Drill]
(1.7-2.0)
1/16 (1.6)	.078 [5/64 (2.0 mm) Drill]
.045 & .052 (1.1 & 1.3)	.062 [1/16 (1.6 mm) Drill]
.023-.035 (0.6-0.9)	.055 [(1.4 mm) #54 Drill]

All dimensions in inches and (millimeters)

Switch Requirements

1/2 Amp AC 24 Volts - Inductive

1/2 Amp DC 24 Volts - Inductive

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