INSTRUCTION / TROUBLESHOOTING MANUAL FOR MODEL A75MD
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SCR/SCR MODULES TROUBLESHOOTING GUIDE
1. Disconnect the positive and negative bus bars from module.
2. Disconnect the secondary wire of power transformer from the SCR/SCR module.
3. Remove both Plug and Play assembly plugs.
4. Measure the resistance from anode to cathode of each SCR. This measurement should read as high
resistance. If the leads are reversed the measurement should also read as high resistance.
5. Measure the resistance of the diode module from anode to cathode. When forward biased, resistance
should read low, when reverse biased, resistance should read high.
6. If the resistance readings do not match the steps above, it is likely that the SCR module or diode module is
defective.