Lincoln Electric IDEALARC CV-250 - Manual (Page 26)

E-7 TROUBLESHOOTING E-7
CV-250
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.
CAUTION
Procedure for Replacing PC Boards
Before replacing a PC board which is suspected of
being defective, visually inspect the PC board in ques-
tion 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 prob-
lem. 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.
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 work-
ing on this equipment.
• Do not touch electrically hot parts.
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WARNING
PC BOARD TROUBLESHOOTING
PROCEDURES
CONTROL PC BOARD
The Control PC Board controls all machine functions
including the thermal protection indicator light and the
Meter PC Board. Most problems, if not caused by
faulty wiring machine misuse, will stem from a faulty
Control PC Board.
Perform the following diagnostic procedure before
replacing the Control PC Board.
1. Turn off the input power at the fuse box.
2. Check for loose connections in the PC Board
plugs, particularly J3.
3. Disconnect the J3 plug from the Control PC Board.
Measure the resistance between the following wire
terminals in the plug:
A) Between wire #200 and wire #201.
B) Between wire #202 and wire #203.
Both of these resistances should be less than 1 ohm.
If these resistances are not less than 1 ohm, check the
wiring back to the main transformer.
If these voltages are less than 1 ohm, refer to
"Procedure for Replacing PC Boards."
METER PC BOARD
When the Meter PC Board malfunctions, first determine
if the rest of the machine functions correctly. If so, then
the problem is in either the harness between the meter
and control boards, or in the meter board itself. Refer
to "Procedure for Replacing PC Boards". As a last
resort, the Control PC Board may have to be replaced.