Lincoln Electric SVM188-A Service Manual page 58

F-18
LED5
LED6
PROCEDURE
WARNING
ELECTRIC SHOCK
• Do not touch electrically hot parts.
1. Disconnect the AC input power to the DC-600
machine.
2. Locate the firing board on the left side of the con-
trol box.
3. Perform a visual inspection on the firing board to
see if there are any loose or faulty connections or
physical damage.
4. Connect the correct AC input power to the DC-600.
5. Turn the power switch (SW1) to the ON position.
6. LEDs 7, 8 and 9 should be lit and equally bright.
See Figure F.4 to locate the LEDs. The three LEDs
should be of equal intensity. If not correvt, see the
PC Board Troubleshooting Guide.
TROUBLESHOOTING AND REPAIR
FIRING BOARD TEST (continued)
FIGURE F.6 FIRING BOARD
LED8 LED9
LED3
LED4
G3742-[ ]
can kill.
DC-600
LED7
LED1
LED10
LED2
FIRING BOARD
7. Trigger the DC-600 using the Output Terninal
Switch and see that LEDs 1 thru 6 and LED 10
come on.
NOTE: LEDs 1 thru 6 should alwaysl be the same bril-
liance as each other. The brilliance will vary as
the Output Control is changed.
8. If LED 10 does not come ON, perform the Internal
Trigger Test.
9. If LEDs 7,8 &9 are ON and any of LEDs 1 thru 6
are not ON, turn the machine OFF , disconnect J4
and re- energize the machine. All six LEDs should
be ON very bright. If not Replace the Firing Board.
If so perform the SCR Bridge Test.
10. If LEDs 7,8 &9 are ON and any of LEDs 1 thru 6
are not the same briliance as the others, Perform
the SCR Bribge Test. If OK, replace the Firing
Board.
11. If LEDs 1 thru 6 do not change as the output con-
trol is varied:
• Check the Output Control Potentiometer.
• Make sure that the Local/Remote Switch is in
Local and functioning properly.
• Perform the Control Board Test. If OK, replace
the Firing Board
F-18
J5
(205) 8
16 (204)
(206) 7
15 (203)
(207) 6
14
(208) 5
13 (231)
4
12 (215)
3
11
2
10
1
9
J6
J7
J8
J4