－
65
－
12. MAINTENANCE AND TROUBLESHOOTING
(Continued)
12.2 Precautions for Replacement of the Printed Circuit Board( Continued)
2) Verify that the plug-in numbers printed on the circuit boards are in accordance with those
on the bunched wires, and then plug them in place firmly after confirmation. Wrong insertion
or connection may damage the circuit boards and even the entire machine.
3) Do not turn on the power switch when connector assemblies of circuit boards are pulled
out.
12.3 Insulation Resistance Test and Withstanding Voltage Test
WARNING
To avoid electric shocks, observe the following precautions.
⚫
Insulation and withstanding voltage test shall be carried out by personnel who have
knowledge and skills for the safety operation, and barriers, etc. shall be set up around the
welding power source to forbid the access of unnecessary people. Confirm that the
capacitance has discharged completely before the operation.
⚫
Perform the insulation and withstanding voltage test as follows.
Refer to the Electric Connection Chart, Parts Configuration Chart and List of Parts for overhaul.
1)
Remove all ground wires for the housing (wire number 80).
2)
Pull out the plug-in CN4 on P30110R.
3)
Short-circuit the AC side and rectifier side of DR1.
4)
Short-circuit TR1 (3)-(1), (1)-(2), TR2 (3)-(1), (1)-(2)) one by one.
5)
Short-circuit the positive and negative charges of diode DR2–DR4.
6)
Short-circuit all input terminals and output terminals.
7)
Close NF (ON).
Restore all wiring after completion of the test.
Please perform
connection according to
plug-in number.
