MW4390W Samsung Microwave - Instructions

Removed control panel, discharged HV capacitor. Removed old diode, tested to confirm failure. Replaced part. Other than the removal of the panel swapping the part was almost as easy as replacing a light bulb.

I removed the outer cover and exposed the inner workings. I watched a video on partselect.com to show how to remove and replace the Diode. I followed the instructions and it was very easy to replace.

Unfortunately, the diode was only part of the issue. I ended up replacing the High Voltage capacitor and Magnetron also. Those w ... Read more ere a little more complicated but still easy to do.

Now the Microwave works just like new! Cost me less than $100 for all parts.

The high voltage tired was shorted. I replaced it with a new one, but that did not solve the problem.

You can test the high voltage tired with a voltmeter and a 9 V battery. Search Search for it on YouTube.

You can also test the high voltage capacitor, the high-voltage transformer, and the magnetron with a multi met ... Read more er. Search for the procedures on YouTube.

I tested all these high-voltage components with a low-voltage multi meter, and they all checked out OK (after replacing the diode). However the microwave still did not heat food.

When working on a microwave it is important to unplug it and also discharge the high voltage capacitor. The capacitor has a 10 megaohm resister to automatically discharge itself, but it may have failed – – so discharge it manually.

In the end I ordered a new microwave.

Snipped four corners off inspection panel,removed one phillips screw and two elect. Connections. Reverse process.

My repair went terrible as I was sent the wrong motor 2 times. My stove sat in the middle of my small kitchen for 2 weeks. Finally the 3rd was the correct one except I didn't have the right nut so I waited another day for that to be sent. Everything working good now, I just hope the bottom fan doesn't go out after this experience.

Pretty easy tear down and assembly once I removed it from cabinet (built in micro)