Question about Panasonic NN-T990SA Microwave Oven
Well this sure stinks. For the last week the microwave has been making this high pitch squeeling noise for about ten seconds before it made its usual heating hum. The other morning it stopped making that noise and no hum anymore either. The fan runs, the turntable turns the timer times but it won't heat. Also the timer when set for one minute goes for exactly 22 seconds after starting and then the machine completely shuts down. Any thoughts would be appreciated.
This model uses an inverter to produce high voltage instead of a convential transformer system. While an inverter (switched-mode power supply) is more efficient from a power consumption standpoint, it is more complex, thus more statistically prone to fail. These should only be examined and worked on by someone who has the necessary technical qualifications. Seriously. Often the machine-soldered connections in a microwave inverter are too weak, so they eventually fail, especially if heat is high in the area. They sometimes fail catastrophically. When not catastrophically damaged, you may hear clicking or squealing and may smell an electrical odor, which is sometimes obscured by the cooling fan. Some manufacturers do not encourage or assist technicians to repair microwave inverters. Most offer the inverter as a whole assembly. But sometimes that is actually cheaper than the time and labor required to fix the old one. If a technician is willing and able to troubleshoot and repair the inverter to component level, it will may be expensive, but may be worth it, especially if he or she will resolder and reinforce connections as needed as part of a thorough repair. That could easily make your inverter beter than a new one! You might be able to get some verbal estimates if you call Panasonic-authorized repair shops and ask then specifically about inverter repair and inverter replacement costs for your model number.
Posted on Dec 23, 2006
Nn-t990sa model microwaveoven when start the oven after 20 seconds come back to stop mode , i replace the magnetron also samea problem, what is problem...
Posted on Sep 06, 2008
It is the magnetron. to fix mine, it cost about $55 for labor plus $5 for shipping for a total of $60. the part was still covered under the 5yr warranty.
Posted on Nov 16, 2007
could it be that i didn't follow the manuel because i got it second hand or is it because something is wrong with it,and i have to get it fixed.
Posted on Oct 21, 2008
Not sure of the TT series models but for the NN series models the procedure is as follows:-
If "Child" is displayed in the display window, then the child safety lock is on.
To remove the child safey lock, press the "Stop/Reset" button 3 times in fairly short succession (less than 3 seconds). The time of day or just the Colon sign (:) is then displayed
If you later want to apply the Child safety lock, then, when the time of day (or colon sign) is displayed, press "Start" 3 times (again in short succession).
Hope this helps
Posted on Nov 08, 2008
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