Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
:!:
View attachment 63973
BE CAREFUL BEFORE TOUCHING THE MAGNETRON AND BE SURE THE MAINS IS DISCONNECTED AND ALL CAPACITORS DISCHARGED
Unplug all the wires from magnetron carefully and take note for the connections (as the wiring is critical).
1. Now with the multimeter set on LOWEST resistance range check both terminals resistance, should be less than ONE Ohm (Ω).
2. Now select the meter's HIGHEST resistance range and check from any terminal (infact the filament connections) to the metal housing resistance , DO NOT TOUCH any probe test terminals at this point. No resistance should be shown, if there is any, the Magnetron is BAD.
Hope it is helpful.
Raza's tests are for the filament and leakage and are good. However, if you want to test it for efficiency there is no way other than to power it up and detect the RF leaving the antenna port. This is a highly specialized job and unless you have the equipment to do it, I strongly suggest you do not try. The voltages and RF radiation from a magnetron are absolutely lethal and both can result in instant death.
Also beware that they MUST be force cooled while operating and they contain strong magnets.
Brian.
Don't worry , tell me about the equipment required to carry on this specialized job .... How to detect the RF leaving & antenna Port ?
thanks
To test the magnetron RF power requires very specialized test equipment but it sounds like you are trying to repair a microwave oven. The RF testing kit would cost about as much as 500 new ovens so unless you are doing this as a business I would stop right now!
What exactly are you trying to do? If you have a microwave oven with a non-functioning keypad it is very unlikely to be anything to do with the magnetron. What fault symptoms do you see.
Brian.
RF testing kit is real expensive tool and needs special skill to use without getting harmed from the High Voltage or the RF power, as both are dangerous to the life.
On the keyboard question, there are many possibilities to this defect. You are needed to put here some symptoms to guess the fault.
May be just DC supply Bad (5 volts to MC) or may be some gating circuit integrated with microcontroller or some ROW and COLUMN generator (still a lot of possibilities)
My test procedure in post #2 was just for a beginner. As to test Magnetron in Live Circuit is a specialized job.
Symptom 1. Check the supply voltage for their proper limits and if not correct them.
Symptom 2. Any gating circuit can be tested for proper working with a Logic gates IC tester.
Symptom 3. For testing Digital special circuits a Skilled person must have the knowledge of those.
If the supply is gone bad has different effects of different situation. If regulated supply is BAD and gone to its highest level caused by a short circuited series regulator, the all ICs may had (repeat may had gone) bad but if gone bad to no supply voltage then you have to check the culprit of failure.
Almost certainly there is a microprocessor driving the display and keys to enter the time/power/start/stop and so on. The microprocessor requires a power source and this is one of the first things to suspect as being faulty if the unit doesn't work. The microprocessor is probably a generic type but programmed at the factory and stamped with a custom part number, without knowing what it's real part number is you can't tell what the supply to it should be. Typically the supply voltage is 3.3V or 5V but if the display is flourescent it may also need a low AC voltage for the filament and a high voltage (> 20V) for the display segments. Without a service manual it is almost impossible to say what the voltage should be and one model will be different to the next.
Brian