Do-it-yourself microwave repair: detailed instructions and video


The microwave oven is a great helper in the kitchen. She cooks, fries, defrosts and reheats food. It becomes sad if it sud­den­ly stops work­ing. How to be? Take it to the work­shop? There, unequiv­o­cal­ly, they will ask for a lot of mon­ey. Microwave repair often costs a lit­tle less than the cost of a new device. What to do? Try doing your own microwave repair.

Microwave device

Repair at home of the fur­nace begins with the dis­as­sem­bly of the device. So, what is includ­ed in this rec­tan­gu­lar device?

  • cham­ber with a plate for prod­ucts;
  • door (the ele­ment has a seal);
  • pow­er cord;
  • mag­netron (gen­er­ates ener­gy);
  • high volt­age fuse;
  • a device that con­verts ener­gy (trans­former);
  • rec­ti­fi­er (high volt­age diode);
  • capac­i­tor;
  • fan.

What is a microwave

Sec­ondary ele­ments:

  • grill lamps;
  • fan motor;
  • back­light lamps;
  • pal­let motor.

These ele­ments are con­nect­ed in series. Open­ing the lid of the device, the main ele­ment, the mag­netron, will be vis­i­ble to the eye. It is pow­ered by the fol­low­ing high volt­age cir­cuit: a trans­former, a fuse, a huge capac­i­tor, a diode.

Principle of operation

  1. The pri­ma­ry wind­ing of the trans­former (wound cop­per wire) is locat­ed at the bot­tom. It has a volt­age of 220 V.
  2. Fur­ther in the cir­cuit are two sec­ondary wind­ings. One of them (cath­ode heat­ing) is a wound cop­per wire near the pri­ma­ry. It has 6.3 V. This AC volt­age stim­u­lates the elec­trons to move off the sur­face. The oth­er wind­ing is locat­ed a lit­tle high­er. Here 2 kV. The volt­age goes out.
  3. The out­put of the cir­cuit is blocked by a capac­i­tor shunt­ed by a diode. Such an anal­o­gy of the arrange­ment of ele­ments gives the fol­low­ing effect: a neg­a­tive half-wave goes direct­ly to the cath­ode ele­ment, and the oth­er, pos­i­tive, charges the capac­i­tance. Grad­u­al­ly, a volt­age of 4 kV is obtained, and the gen­er­a­tion process begins.
  4. The cath­ode receives volt­age from the sec­ondary heat­ing wind­ing of 6.3 V. The mag­netron anode is con­nect­ed to ground. The coil, which per­forms the heat­ing func­tion, is elec­tri­cal­ly con­nect­ed to the cath­ode. The pow­er of the mag­netron ele­ment is con­trolled by the device’s timer.
  5. The pro­gram­mer con­trols the oper­a­tion of the device. It has a gear train that reg­u­lates the time. The longer the ele­ment of the mag­netron device works, the more pow­er is giv­en to the dish. And vice ver­sa, if the mag­netron works a lit­tle, then it pro­duces the same amount of pow­er.
  6. Open­ing the door stops the oper­a­tion of the device. A pro­tec­tive relay is respon­si­ble for this process.
  7. A high-volt­age fuse pro­tects against idle oper­a­tion and the ingress of tin objects. In case of an acci­dent, it burns out.
  8. The above sec­ondary mech­a­nisms are con­nect­ed in series. This fact makes it eas­i­er to repair microwaves with your own hands. Since, if at least one ele­ment does not work, then the entire device does not per­form its func­tions. The excep­tions are the start­ing relay and the mag­netron.

Popular causes of breakdowns

Device can­not turn on

Why did it hap­pen? Because an ele­ment such as a fuse has bro­ken.

How to repair a microwave? Replace with a new fuse. After the spec­i­fied action, check the safe­ty diode of the trans­former and the trans­former itself for ser­vice­abil­i­ty.

How to find the fuse in the device? This is a glass spray with a thin wire and a small spring inside. In work­ing con­di­tion, the spring is stretched. Pro­tects the fuse sleeve made of plas­tic.


How to check if it works? Dis­con­nect the fuse from the cir­cuit and check with a car bat­tery and an incan­des­cent lamp of the mark­er lights. The lamp is on — the ele­ment is work­ing, off — it is not work­ing.

The clock on the dis­play works, but the device does not heat up

Why? It’s a bro­ken door switch.

How to decide? Replac­ing a bro­ken item with a new one or (if pos­si­ble) repair­ing.

The device turns on inter­mit­tent­ly

How to accu­rate­ly rec­og­nize the prob­lem? The device will first turn on, and after a few min­utes, it will turn off. The process is repeat­ed in a cir­cle.

It’s the cool­ing fan that stopped work­ing. The switch­ing relay may break in it or the ven­ti­la­tion holes may be closed.

Solu­tion: replace the ele­ment with a new one.

Sparks are vis­i­ble from the cam­era and it smells of burn­ing

The rea­son lies in the con­t­a­m­i­na­tion of the mica gas­ket. The dirt caused the ele­ment to burn out.

In this case, you will have to repair the device by replac­ing the burnt ele­ment.

Microwave does not heat food

The device can­not heat food due to low mains volt­age or loss of mag­netron emis­sion.

Repair­ing a break­down will require spe­cial equip­ment (for exam­ple, a volt­age sta­bi­liz­er). Ques­tion: Is it worth it to repair a bro­ken microwave oven your­self? Every­one must answer it on their own. With a pos­i­tive deci­sion, it will be nec­es­sary to increase the num­ber of turns or com­plete­ly replace the mag­netron.

Microwave dis­play not work­ing

In the event of a break­down, the dis­play does not show the val­ues ​​com­plete­ly, with spots. Most like­ly, the proces­sor is dam­aged and needs to be replaced. The fact that the device does not turn on speaks in favor of the proces­sor.

Anoth­er option: the break­age of the screen itself.

Con­trol pan­el not work­ing

The touch pan­el dis­plays the oper­at­ing time of the machine. If it does not work, then the tracks that con­duct cur­rent are dam­aged.

Repair of the touch pan­el comes down to the com­plete replace­ment of bro­ken ele­ments or to the impo­si­tion of wires.

Tray does not spin smooth­ly

If the plate inside the microwave turns uneven­ly, with jerks, then the grooves of the rollers are dirty. Anoth­er rea­son: the engine broke down.

Exit: clean the grooves of the rollers from con­t­a­m­i­na­tion or replace with a new engine. Also read the arti­cle what to do if the plate in the microwave is not spin­ning.

What the engine looks like, its com­po­nents, how to dis­as­sem­ble and repair it, you will see in this video:

The light inside is on, the plate is spin­ning, but the food is not heat­ed.

Caus­es: large volt­age drop, changes in the pow­er cir­cuit, fail­ure of the mag­netron.

How to decide? It is nec­es­sary to ring the trans­former cir­cuit and fix the prob­lems found. Sec­ond solu­tion: replace the alter­na­tor.

Con­trol pan­el but­tons not work­ing

With this break­down, do-it-your­self microwave repair comes down to a care­ful check of the cir­cuit with a tester, replac­ing bro­ken but­tons and sol­der­ing the con­tacts.

Extra­ne­ous hum at work

The rea­sons for the break­down of the fol­low­ing ele­ments: fan, trans­former, diode.

How to decide? Replace ele­ments.

Microwave won’t turn off

Diag­nos­tics: The device is con­stant­ly run­ning and can­not turn off.

What’s bro­ken? The rea­son is a mal­func­tion of the sup­ply relay.

How to elim­i­nate? Replace relay. Before doing this, check for dam­age with an ohm­me­ter. There may also be a rea­son in the proces­sor itself or the con­trol cir­cuit.

Replacing elements

Bro­ken ele­ments can be eas­i­ly replaced with new ones? Where can you get these items? Any spe­cial­ized store. If you are at a loss with the name of the ele­ment, dis­as­sem­ble the device, take the bro­ken part to the store, show it to the sell­er. He will help you make the right choice.

When repair­ing with your own hands, the most expen­sive will be the pur­chase of a capac­i­tor (about 600 rubles), and the cheap­est — a fuse.

Inter­est­ing to know: what is con­vec­tion in a microwave.





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