Have a good day Sir, I have a DeLonghi Microwave model MW605. Right now it does not work, it always blown up the fuse. I inspect high voltage Capacitor, it is good. I check the high voltage diode, it is also good. Only the resistor across the terminals of the capacitor it shows infinitive when measured by Megohm. Does it cause the fuse blown up?. I saw it said in Capacitor label, the resistor is 10 Megaohm? I also measured the Magnetron between the two terminals, it is 0.5 Ohm and terminals to body is infinity. Appreciate much if you can give me some hint to repair my microwave. Thank you [email protected]
Thank you very much for your hint. I changed the transformer and it works now. I feel happy when the problem solved by my hand with your great help. You are really very good expert in both theory and practice. Best regards, Cuoitoet
Posted on May 12, 2007
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When does the fuse blow? If it blows the fuse as soon as you hit START, you probably have a high voltage capacitor shorting. Does it blow a few seconds after you press START? If so, then it may be a bad high voltage transformer. Does it blow when you open or close the door? If so, it may be a bad door swithc or a misaligned or damaged door or door switch mount. Please give more details.
Posted on May 08, 2007
For more information on safely checking the high voltage transformer, see:http://www.gallawa.com/microtech/xformer...
If you need further help, see this:http://www.gallawa.com/microtech/how_wor...
This is how a microwave oven works. A detailed, illustrated explanation.
Thanks for your kind ratings!
Please be aware that the voltages present in the microwave can be instantly lethal!
You must avoid contact with and wires or components while the unit is plugged in.
Also, the capacitor can store a charge that can possibly cause injury after the unit has been unplugged.
The transformer measurements sound good, but it could still be bad. The windings could be heating up and shorting once energized.
You can unplug the microwave, disconnect the high voltage output lead from the transformer, tape it lightly to prevent any shorting, and run the microwave.
If it blows the fuse, it's not the transformer.
Then you'd need to unplug the oven, plug the high voltage lead back in, then disconnect one high voltage item, test the unit, etc.
At this point it's hard to say without such testing, but I would suspect the transformer.
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Thank you very much for your suggestion. I will check the transformer, because the fuse blow after few second (may be ten second) and I saw the fuse become red, immediately I press the stop button, then I save the fuse.
Do you have any hint for me to check the transformer? primary coil or secondary coil?. I think you are really a very good expert. Awaiting for your advise.
Dear sir,
I followed your comment/instruction to check the transformer and following is the result:
- High voltage terminal to chassis: 112 Ohm
- Primary terminals: 1.9 Ohm
- Primary terminal to chassis: infinitive
- Between Filement terminals: 0.2 Ohm
- Filement to chassis: infinity
I also measured Magnetron terminals: 0.2 Ohm and Filement terminals to chassis is infinity.
Could you pls. advise what component (transformer or Magnetron) is failed?
Thank you very much for your help.
Your sincerely
Dear sir,
I followed your comment/instruction to check the transformer and following is the result:
- High voltage terminal to chassis: 112 Ohm
- Primary terminals: 1.9 Ohm
- Primary terminal to chassis: infinitive
- Between Filement terminals: 0.2 Ohm
- Filement to chassis: infinity
I also measured Magnetron terminals: 0.2 Ohm and Filement terminals to chassis is infinity.
Could you pls. advise what component (transformer or Magnetron) is failed?
Thank you very much for your help.
Your sincerely
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