Microwave ovens are essential appliances in most households for quickly heating, cooking, and defrosting foods. However, like all appliances, microwaves can break down over time and stop functioning properly. Instead of purchasing a costly replacement, many microwave issues can be easily diagnosed and repaired at home.
This comprehensive DIY guide will walk you through the microwave repair process from start to finish. We’ll cover microwave safety procedures, diagnosis techniques, common problems and fixes, step-by-step directions for repairs, and replacement part recommendations.
Follow along to learn how to bring your faulty microwave back to life or use this as a reference next time your microwave needs a repair.
Essential Microwave Safety Precautions
Working on an appliance that generates high voltages like a microwave can be extremely dangerous if proper safety guidelines are not followed. Here are the key precautions to take before you begin any microwave repair:
- Always unplug the microwave before beginning work
- Give the microwave capacitors time to discharge their stored voltages after unplugging
- Do NOT attempt to repair the microwave’s high voltage diode or magnetron components yourself
- Avoid making contact with exposed electrical parts or wiring
- Ensure hands are dry before working on any electrical appliance components
- Use care when reaching into the metal casing which can have ungrounded parts
- DO NOT turn on or energize the microwave until all work is complete
Neglecting any of these microwave safety rules risks potentially fatal electrical shock hazards. If you are uncomfortable working around exposed high voltage electronics, it’s advisable to hire a professional for microwave repair.
How to Diagnose Microwave Issues
Before you can execute a proper repair, you’ll need to correctly diagnose the underlying issue with your microwave. Here is a step-by-step guide to microwave troubleshooting:
- Document exactly when/how the failure occurs
- Does the microwave immediately trip a breaker upon startup?
- Or does it fail only while operating during cooking?
- Can you operate any functions like the internal light?
- Perform a detailed visual inspection of all components
- Look for any visibly damaged parts, faulty wiring connections, burns, etc.
- Pay close attention to safety interlocks, door seal, and area around the magnetron
- Inspect the glass turntable and support ring underneath for any cracks
- Test microwave functionality
- Attempt to use different cooking power levels
- Try operating just the microwave light on its own
- Does the failure happen only during specific functions?
- Determine which components could be the likely culprit
- Review this list of common microwave issues and fixes
- Isolate if the issue lies in the control board, door switches, magnetron tube, user interface or elsewhere
Thorough troubleshooting is crucial before attempting any repair work on your microwave. If the issue remains unclear, don’t hesitate to call in a professional service technician.
Common Microwave Problems and Fixes
Here is an overview of frequent microwave failure points along with their typical DIY fix recommendations:
| Issue | Possible Cause | Fixes |
| Microwave trips breaker or blows fuse upon startup | Damaged magnetron high voltage circuitry or capacitors | * Replace capacitors<br>* Potential need for professional magnetron replacement |
| Sparking visible during microwave operation | Faulty magnetron connections or antenna cover | * Inspect/repair connections<br>* Replace antenna cover |
| Microwave light fails to operate | Burnt out light bulb | * Simply replace light bulb |
| Microwave cooks unevenly or food remains cold | Broken or obstructed door seal, faulty stirrer fan | * Replace worn door seal<br>* Replace faulty fan motor |
| Microwave buttons not responsive | Loose wire connections or faulty control board | * Check and reconnect any loose wires<br>* Replace faulty control board |
| Microwave turntable fails to rotate | Broken turntable, support rollers, belt or motor issue | * Replace turntable parts<br>* Repair/replace motor |
| Microwave does not heat at all | Magnetron filament failure, faulty high voltage diode or capacitor | * Generally requires professional magnetron and part replacement |
While most microwave issues can be solved with simpler fixes like replacing a cheap component, repairs involving the high-voltage magnetron transformer or circuitry elements should be left to qualified professionals due to potential electric shock risks. Don’t hesitate to call your local appliance repair service for assistance on repairs beyond your technical capabilities.
Step-by-Step Microwave Repair Directions
Once you’ve isolated the issue with your microwave through troubleshooting, follow these step-by-step instructions to safely complete repairs:
Always Unplug Microwave First
Before any work, unplug the microwave to disable electrical power!
Remove Outer Case
- Remove the glass turntable and rotating ring from inside the microwave
- Take out any screws on the microwave rear/side panels or on built-in installation brackets
- Carefully maneuver the microwave to access rear/side case panels and disconnect any wiring plugs
- Lift off the outer case panel
Diagnose and Replace Faulty Parts
- Visually inspect the exposed microwave components and wiring for damage
- Refer to the common microwave issues table to help diagnose
- Order any replacement parts needed before continuing
- To replace parts, first remove any brackets or screw mounts before gently disconnecting wiring plugs
- Ensure replacement components match wiring configurations of the old part removed
Reassemble Microwave
- Carefully reconnect all wiring plug mounts to replacement components
- Reattach any component brackets or screw mounts
- Replace the microwave outer case panels in reverse order of removal
- Reinsert glass turntable and ring, plug back in microwave
Again, DO NOT attempt to replace or even touch hazardous high-voltage components like the microwave diode or magnetron unless you are an experienced electrical professional.
Recommended Replacement Microwave Parts
Here are the most commonly replaced microwave parts with component examples and typical pricing:
| Part | Example Replacements | Estimated Price |
| Fuse | 3A 250V Fast blow fuse, 5A 250V Slow blow fuse | $1 – $3 |
| Light bulb | 15W, 25W or 40W appliance bulb | $2 – $5 |
| Capacitors | 1200MFD 125V Capacitor | $3 – $7 |
| Diode | High voltage microwave spec diode | $5 – $15 |
| Magnetron | 1250 Watts, 900 Watts replacement | $30 – $50 |
| Door Interlock Switches | Roller lever style, plunger style | $10 – $15 |
| Control Board | Replacement main logic board | $40 – $70 |
| Glass Turntable | 12, 13 or 14 inch diameter turntable | $15 – $25 |
| Motor | New stirrer fan or turntable rotation motor | $30 – $60 |
Buying the right spec part that matches your existing microwave components is key. Before ordering online, verify the part number, rating requirements and physical size dimensions. Also be sure to purchase from a reputable dealer for reliable replacement parts.
Also Read: How to Install and Replace a Microwave
Conclusion
There’s no need to discard an old microwave just because it breaks down or stops heating properly. Oftentimes, the solutions are basic fixes like replacing fuses, light bulbs or worn parts. And while advanced repairs relating to high voltage microwave circuits do require expert handling, many issues can be solved affordably with generic replacement parts ordered online.
We hope this definitive DIY guide gave you the troubleshooting tips and repair how-to’s needed to revive an aging or faulty microwave oven. Just be sure to always place safety first by unplugging the microwave and avoiding contact with hazardous internal components.