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How to troubleshoot an electrical short to ground, blown fuse or a power supply on any machine.

Electrical shorts- Fuse blown, Power supply voltage pulled down, ground fault

1. Pull fuse out, and power on machine. There should be 2 contact points where fuse was removed. Check with a meter each point to find the incoming power leg to the fuse. If no power is on either side, determine what power supply feeds the fuse.

2. Before troubleshooting the electrical short power down machine put your meter on the ohms setting and place one leg of your meter on the side that did not have the incoming power on. Place the other lead on a ground terminal in your electrical cabinet. Ohm reading will usually be above 80ohms but not always. This depends on the largest smallest ohm reading of all the coils within the circuit(ice cube relay coil/contactor coil etc.) If its shorted its usually about 0-3 ohms. If its an intermittent short it could be difficult- start by checking all movable cables and cable carriers for abrasion or chip contamination.

3. Next if you have prints. Follow through the circuit to see where the wires go (this may not work if it goes to a common terminal strip that branches out to many devices. If its a common terminal strip, start pulling off maybe half of the wires that are labeled the same, leave the main wire from the fuse connected to the terminal strip. Then check at the fuse again to ground. See if the ohms go up, if not pull off another section of wires and check again. Keep using this process of elimination to determine what wire is causing the drop in ohms (short).

4. Then follow that wire or cable to see where it goes. If you find another terminal strip perform the same test until you find the source of the short. Then troubleshoot that device until you find the electrical short or cause of the problem..