Transformers, like any products we use are subject to wear and tear. This is why it is very important to also be informed of ways on how to deal with these in case of any inconsistency or irregularity which may already be a sign of failure.
This post is to a simple guide on simple troubleshooting steps that can be done.
NOTE: It is still recommended to let a professional handle repairing and restoring of electrical or electronic products including step-down transformers.
Use a Digital Multimeter
Using a Digital Multimeter (DDM), try to test for some turn-to-turn shorts. You can do this by setting your DDM to a high resistance level like 2 megaohms. Then, make sure that one of the probes touch the primary winding while the other touches the secondary winding terminal. You have to repeat this for each secondary coil. Your DDM should read “infinite” resistance on it. If you detect turn-to-turn shorts, it means that the transformer is already problematic and it has to be replaced.
Test for lamination shorts
After testing for some test-to-test shorts, you may now proceed to testing for lamination shorts. This step is something that is similar to the first step, except that you have to place one of the probes on the winding terminal while keeping the other on the metal frame. Make sure that the probe touches bare metal. In case of a nonmetal finishing, try to scratch the metal frame using the probe. This way, you can scrape the finishing off and therefore allow the probe to touch the metal part.
Check the transformer’s continuity
The next thing to do is check for the transformer’s continuity. This is done by placing the probe across each winding’s terminal. Then, you have to set the DMM at a low range like 200 ohms. If your DDM indicates a high reading or an “open circuit,” it means that your transformer could be either partially or completely open. This is a bad sign. Meaning, you have to get a new transformer.
Check your transformer’s voltage output
Lastly, check your transformer’s voltage output. Using the Test Jumper, connect your transformer’s primary winding to a 110-volt source. Make sure that the alligator clips are not touching each other. They should not touch any grounded surface, too. You also have to keep in mind never to touch either the clips or the primary winding when the cord is plugged in as you will surely get a fatal shock. Then, set the DDM at on a proper alternating current voltage range. Do this for each secondary winding through placing the probes across each terminal. Note each voltage reading.
When performing these troubleshooting methods, make sure that you are careful enough not to touch parts that might cause groundings or burns. Keep in mind that regardless of how low the voltage may be, it could still be dangerous.