FIRING BOARD
G3742-[ ]
LED7
LED8 LED9
LED1
LED2
LED3
LED4
LED5
LED6
LED10
J5
J6
J7
J4
J8
(205) 8
(206) 7
(207) 6
(208) 5
4
3
2
1
16 (204)
15 (203)
14
13 (231)
12 (215)
11
10
9
FIGURE F.1 – FIRING BOARD LEDs
PC BOARD TROUBLESHOOTING GUIDE (continued)
FIRING BOARD
1.
With DC-600 set for the
Test Conditions
all ten
LEDs on the Firing Board should be lit.
2.
LEDs 7, 8 & 9
indicate that the three 34vac sup-
plies from the Main Transformer are present on the
Firing Board. They should all be ON whenever the
Power Switch is ON.
• If any are not ON check the voltages at P5
• If voltage is present and the LED is OFF, replace
the Firing Board
3.
LED 10
indicates that the machine is “triggered”
(Output Terminal Switch ON).
• Alternate Trigger Methods:
Operate Wire Feeder trigger.
Place a jumper across 2 & 4 on T.S.2.
Jumper between pins C & D of 14 pin connector.
• If LED 10 does not come ON, check wiring.
Perform the
Internal Trigger Circuit Test.
4.
LEDs 1 thru 6
indicate that gate signals are being
sent to the SCRs in the Main Rectifier.
These
LEDs will vary in brightness as the Output Control
is changed.
• It is important that all six LEDs are the same bril-
liance as each other.
If none are lit, check the voltage at lead 231
(P5 - Pin13). See the
Control Board Test
. If
OK, Replace the Firing Board.
If LEDs are not the same brilliance, see the
SCR Bridge Test
and check the connections
to J-4. If OK, replace the Firing Board.
TROUBLESHOOTING AND REPAIR
F-10
F-10
DC-600
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Section
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Master
T
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LED that
was off
7
8
9
Check AC voltage between pins specified,
it should be approximately 34VAC .
P5 pins 15 & 16 (wires 203,204)
P5 pins 7 & 8 (wires 205,206)
P5 pins 5 & 6 (wires 207,208)
