| TROUBLESHOOTING |
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| Observe all Safety Guidelines detailed throughout this manual |
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PC BOARD TROUBLESHOOTING GUIDE - FIRING P.C. BOARD
1.LEDs 1 through 9 must be lit when the
2.LEDs 7, 8, and 9 indicate AC power being supplied to the P.C. board from auxiliary windings on the main transformer (T1). If a LED is not on, turn the machine off and unplug P8 from the firing board. Turn the machine back on and check the following voltages:
3.If all voltages are present, turn power off, and plug P5 back into J5. Turn power back on. If LEDs 7, 8 or 9 are still not lit, replace Firing PCB.
4.If voltages were not present, check the circuit back through the external dropping resistors to the auxil- iary windings for a possible open resistor or wire.
5.LEDs 1 through 6 indicate gate signals are being sent to the main SCRs 1 through 6 respectively. If LED2 on the Control board is bright, along with LEDs 7, 8, and 9 on Firing board, and LEDs 1 through 6 are unequal in brightness, check to make sure lead 231 between Control board and Firing board is not broken. (If lead 231 is removed while the machine output is at open circuit, the output voltage peaks may be unregulated and cause the
6.If one or more of LEDs 1 through 6 are off, LEDs 7, 8, and 9 are on and the voltage on lead 231 from the Control board (pin 13, P5 to pin 12, P5) is 3 to 13Vdc replace the Firing PCB.
LED that was off
Check AC voltage between
Voltage should be approximately
7
P8 pins 2 & 1 (wires 283,284)
32Vac
8
P8 pins 4 & 3 (wires 285,286)
32Vac
9
P8 pins 6 & 5 (wires 287,288)
32Vac
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.
