Procedure for Troubleshooting 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.
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.
CAUTION
If for any reason you do not understand the test procedures or are unable to perform the tests/repairs safely, contact your Local Lincoln Authorized Field Service Facility for technical troubleshooting assistance before you proceed.
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