Home |
Search |
Today's Posts |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
LinkBack | Thread Tools | Display Modes |
#1
Posted to sci.electronics.repair
|
|||
|
|||
microwave oven stopping prematurely, repairable?
Hello folks, happy Memorial Day weekend to you all! My microwave is acting erratic, maybe you can help me see if it is repairable? It can heat water, but tends to shut downs prematurely. I have read this repair faq http://www.repairfaq.org/sam/micfaq.htm#micsaf but didn't find answer to my problem. One evening I was cooking a frozen dinner, a chicken pot pie with a mesh for browning at the top of the paper container. It is said to be microwave safe. I followed instructions exactly. But maybe 3 minutes into the nuking, there were a few spark, so I pulled the power cord as quickly as I could. There were some burn smell, which lingered even after a week of non-use. The microwave oven was clean, no spill over or splatter when I started nuking the pot pie. I did not leave a fork in there either. The microwave in question is a panasonic inverter system, 1200 W. manufacture date is 2002. Currently, all electronics seems to work fine, touch pad works, clock runs, timer works. no visible damage. No paint problem from the spark. I tried to heat a cup of water for 35 seconds, and microwave just shut off automatically after some 15-20 seconds (but clock panel still running, so the electronics seems to have shut something down. No error indicator of any sort that I can see). If I set power to 50%, then it will heat the water for 50 seconds to completion. water temperature is very warm to the touch. If I set power to 10%, then it will heat for more than 70 seconds to completion. Maybe eventually at more than 50 seconds even at the 50% power, it might shut off automatically when something gets too hot? I am not sure if I want to try it if microwave isn't really going to be fully functional anyway. It is likely cheaper to just buy a new one, but as an environmentalist, I just hate to waste appliance that can otherwise work Much thanks in advance for any advices. Tin |
#2
Posted to sci.electronics.repair
|
|||
|
|||
microwave oven stopping prematurely, repairable?
tin6150 wrote:
Hello folks, happy Memorial Day weekend to you all! My microwave is acting erratic, maybe you can help me see if it is repairable? It can heat water, but tends to shut downs prematurely. I have read this repair faq http://www.repairfaq.org/sam/micfaq.htm#micsaf but didn't find answer to my problem. One evening I was cooking a frozen dinner, a chicken pot pie with a mesh for browning at the top of the paper container. It is said to be microwave safe. I followed instructions exactly. But maybe 3 minutes into the nuking, there were a few spark, so I pulled the power cord as quickly as I could. There were some burn smell, which lingered even after a week of non-use. The microwave oven was clean, no spill over or splatter when I started nuking the pot pie. I did not leave a fork in there either. The microwave in question is a panasonic inverter system, 1200 W. manufacture date is 2002. Currently, all electronics seems to work fine, touch pad works, clock runs, timer works. no visible damage. No paint problem from the spark. I tried to heat a cup of water for 35 seconds, and microwave just shut off automatically after some 15-20 seconds (but clock panel still running, so the electronics seems to have shut something down. No error indicator of any sort that I can see). If I set power to 50%, then it will heat the water for 50 seconds to completion. water temperature is very warm to the touch. If I set power to 10%, then it will heat for more than 70 seconds to completion. Maybe eventually at more than 50 seconds even at the 50% power, it might shut off automatically when something gets too hot? I am not sure if I want to try it if microwave isn't really going to be fully functional anyway. It is likely cheaper to just buy a new one, but as an environmentalist, I just hate to waste appliance that can otherwise work Much thanks in advance for any advices. Tin is the cooling fan running? |
#3
Posted to sci.electronics.repair
|
|||
|
|||
microwave oven stopping prematurely, repairable?
On May 28, 10:32*pm, mike wrote:
tin6150 wrote: Hello folks, happy Memorial Day weekend to you all! My microwave is acting erratic, maybe you can help me see if it is repairable? *It can heat water, but tends to shut downs prematurely. I have read this repair faq http://www.repairfaq.org/sam/micfaq.htm#micsaf but didn't find answer to my problem. One evening I was cooking a frozen dinner, a chicken pot pie with a mesh for browning at the top of the paper container. *It is said to be microwave safe. *I followed instructions exactly. *But maybe 3 minutes into the nuking, there were a few spark, so I pulled the power cord as quickly as I could. *There were some burn smell, which lingered even after a week of non-use. *The microwave oven was clean, no spill over or splatter when I started nuking the pot pie. *I did not leave a fork in there either. The microwave in question is a panasonic inverter system, 1200 W. manufacture date is 2002. Currently, all electronics seems to work fine, touch pad works, clock runs, timer works. *no visible damage. *No paint problem from the spark. *I tried to heat a cup of water for 35 seconds, and microwave just shut off automatically after some 15-20 seconds (but clock panel still running, so the electronics seems to have shut something down. No error indicator of any sort that I can see). If I set power to 50%, then it will heat the water for 50 seconds to completion. *water temperature is very warm to the touch. *If I set power to 10%, then it will heat for more than 70 seconds to completion. Maybe eventually at more than 50 seconds even at the 50% power, it might shut off automatically when something gets too hot? *I am not sure if I want to try it if microwave isn't really going to be fully functional anyway. It is likely cheaper to just buy a new one, but as an environmentalist, I just hate to waste appliance that can otherwise work Much thanks in advance for any advices. Tin is the cooling fan running? Thanks Mike. And yes, cooling fan next to the power supply runs. I hear humming noise of the microwave coming on, so my guess every moving part is working... -Tin |
#4
Posted to sci.electronics.repair
|
|||
|
|||
microwave oven stopping prematurely, repairable?
It appears that "something" is overheating that causes the klystron to lose
power, and this "something" gets warmer with higher power settings. If that "something" is not a component /intended/ to shut off the unit when it overheats, you'll probably have a hard time finding it. Freeze-spray might locate it. Otherwise, I vote for buying a new unit. |
#5
Posted to sci.electronics.repair
|
|||
|
|||
microwave oven stopping prematurely, repairable?
On May 28, 9:17*pm, tin6150 wrote:
Hello folks, happy Memorial Day weekend to you all! My microwave is acting erratic, maybe you can help me see if it is repairable? *It can heat water, but tends to shut downs prematurely. I have read this repair faqhttp://www.repairfaq.org/sam/micfaq.htm#micsaf but didn't find answer to my problem. One evening I was cooking a frozen dinner, a chicken pot pie with a mesh for browning at the top of the paper container. *It is said to be microwave safe. *I followed instructions exactly. *But maybe 3 minutes into the nuking, there were a few spark, so I pulled the power cord as quickly as I could. *There were some burn smell, which lingered even after a week of non-use. *The microwave oven was clean, no spill over or splatter when I started nuking the pot pie. *I did not leave a fork in there either. The microwave in question is a panasonic inverter system, 1200 W. manufacture date is 2002. Currently, all electronics seems to work fine, touch pad works, clock runs, timer works. *no visible damage. *No paint problem from the spark. *I tried to heat a cup of water for 35 seconds, and microwave just shut off automatically after some 15-20 seconds (but clock panel still running, so the electronics seems to have shut something down. No error indicator of any sort that I can see). If I set power to 50%, then it will heat the water for 50 seconds to completion. *water temperature is very warm to the touch. *If I set power to 10%, then it will heat for more than 70 seconds to completion. Maybe eventually at more than 50 seconds even at the 50% power, it might shut off automatically when something gets too hot? *I am not sure if I want to try it if microwave isn't really going to be fully functional anyway. It is likely cheaper to just buy a new one, but as an environmentalist, I just hate to waste appliance that can otherwise work Much thanks in advance for any advices. Tin Sounds slightly similar. Had a GE unit that started making an internal arc sound [the arc burnt around the waveguide entrance to the microwave chamber out of sight. Without total disassembly could not see it]. Symptom sounds similar, uWave would run, then [in my case] hear arcing sounds, and then shutdown. Arcing did NOT occur if a glass of water were present. But arcing occurred if I was trying to toast something dry, like bread. My guess was that the damped microwave chamber keeps the voltage down enough there is no arcing. And when the chamber is unloaded, the resonant voltages get high enough to enccourage the arcing. Culmination of this was that after 'limping' along for 4 months, the burn spots in the waveguide feed required replacing the unit, had to buy a new one. |
#6
Posted to sci.electronics.repair
|
|||
|
|||
microwave oven stopping prematurely, repairable?
On 29/05/2011 12:17 PM, tin6150 wrote:
Hello folks, happy Memorial Day weekend to you all! My microwave is acting erratic, maybe you can help me see if it is repairable? It can heat water, but tends to shut downs prematurely. I have read this repair faq http://www.repairfaq.org/sam/micfaq.htm#micsaf but didn't find answer to my problem. One evening I was cooking a frozen dinner, a chicken pot pie with a mesh for browning at the top of the paper container. It is said to be microwave safe. I followed instructions exactly. But maybe 3 minutes into the nuking, there were a few spark, so I pulled the power cord as quickly as I could. There were some burn smell, which lingered even after a week of non-use. The microwave oven was clean, no spill over or splatter when I started nuking the pot pie. I did not leave a fork in there either. The microwave in question is a panasonic inverter system, 1200 W. manufacture date is 2002. Currently, all electronics seems to work fine, touch pad works, clock runs, timer works. no visible damage. No paint problem from the spark. I tried to heat a cup of water for 35 seconds, and microwave just shut off automatically after some 15-20 seconds (but clock panel still running, so the electronics seems to have shut something down. No error indicator of any sort that I can see). If I set power to 50%, then it will heat the water for 50 seconds to completion. water temperature is very warm to the touch. If I set power to 10%, then it will heat for more than 70 seconds to completion. Maybe eventually at more than 50 seconds even at the 50% power, it might shut off automatically when something gets too hot? I am not sure if I want to try it if microwave isn't really going to be fully functional anyway. It is likely cheaper to just buy a new one, but as an environmentalist, I just hate to waste appliance that can otherwise work Much thanks in advance for any advices. Tin I have an older MW oven that wouldn't shut down for any irregularity. One day it started sparking and had a smell, just like you said. Upon closer investigation I found that the mica plate in front of the wave guide had deteriorated and had a dark spot that arced under power. I took the mica off and ran the device, and it worked just fine. I ordered a sheet of mica on ebay to cut to size cause I couldn't get the original. Before that arrived I found a MW Oven on the road side for verge collection and removed the mica from there. I trimmed it a little and fitted it in my oven. No problems ever since. Got a spare one now in the junk box Looks like the mica sheets can get damaged and take up moisture, which sort of shorts out the micro wave energy. Don't know if this happened to your machine but it wouldn't hurt to check. Tony Excerpt from the faq: More on the waveguide cover and cleaning That cover is made of an insulator transparent to microwaves, usually mica, not a metal. The material can be obtained from places like MCM Electronics which you then cut to size with a pair of scissors or a paper cutter. First, completely clean below, above, inside, and whatever of the cover material is remaining. All traces of carbon and burnt on food must be removed. In particular, you need to clean inside the waveguide above the inside top of the oven as well. Then run the oven (with the waveguide cover removed, if necessary) to verify that there are no other problems (there probably are none). Sometimes, you need to remove the outside metal cover in order to remove the waveguide cover. There may be little plastic pins or snaps which tend to get gummed up with burnt food and may be difficult to pry off from inside the oven. If you do need to remove the metal cover, jot down the locations of each of the screws (they are not always all alike) and stay away from everything but the waveguide cover itself (especially the high voltage components!). That waveguide cover is not essential to the operation of the oven but it does prevent food from entering the waveguide and getting trapped there. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Microwave oven | Electronics Repair | |||
Microwave oven catches on fire. Repairable? | Home Repair | |||
Microwave oven catches fire. Repairable? | Electronics Repair | |||
Microwave oven | Electronics Repair | |||
Samsung Microwave & GE Microwave oven | Electronics Repair |