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| 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. |
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Panasonic microwave, blown inverter board transformer
Hi, I have an NN-A554W and the transformer on the inverter board has
blown. Microwave wouldn't start cooking so I ran it for a moment with the cover off, transformer did a light and smoke display and now it smells like fireworks. I made sure the magnetron was discharged and between the two connections I am getting 0 ohms, but I only have a basic multimeter. Between those and the casing is open. This microwave is at least 10 years old with a lot of use, so how likely is it that the transformer has just gone by itself vs the magnetron or the small mains input board dying and taking the transformer with it? The other thing is that the part number of the inverter/transformer board is A6645M304GP, and the magnetron is a 2M236-M42. A lot of other models seem to use boards that look identical, but not exactly the same part number. For example I have found a site saying that this magnetron can be used with an A66454T05AP or F66454T07AP board, which do look the same as mine, so are they just a different revision or something or are the differences going to be bigger? Even if I need exactly the same board, it looks like I could be chasing a part that would work in many different models, even different brands, if only I knew which one to look for (it seems there are no parts for my model). Am worried about replacing it and having the new one get instantly blown up though. Andrew |
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#2
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Panasonic microwave, blown inverter board transformer
OK. On the one hand:
Purchase new Board: US$25 + shipping Install New Board: 2 hours work It all works: All good! Magnetron is bad: Purchase new Magnetron for US$65 + shipping Install new Magnetron: 2 hours work. It wall works: 4 hours + US$90 + shipping. On the other hand, a brand new 1,000 watt microwave: US$150, complete with warranty. I admire your wish to reduce landfill, but I have to wonder at the investment in a 10 year old device that is heavily used by your own description. Peter Wieck Melrose Park, PA |
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Panasonic microwave, blown inverter board transformer
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#5
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Panasonic microwave, blown inverter board transformer
1 (800) 211-7262
I entirely understand that this Group exists so that individuals may discuss means-and-methods for doing pretty much anything at all in the hardest possible way, reaching for the least satisfactory results. And that includes reaching around the world for S.W.A.G., anecdotal experiences and arbitrary suggestions. Rather than going to the Mother Ship and asking there. Panasonic Customer Service number above. Then: https://www.justanswer.com/sip/panasonic-help-24-7?r=ppc|ga|27|Tech-CE-SQR-Search-BMM|CE-Panasonic|&JPKW=%2Bpanasonic%20%2Bengland&JPDC=S&J PST=&JPAD=378934176681&JPMT=b&JPNW=g&JPAF=txt&JPRC =1&JPCD=&JPOP=&cmpid=2032112328&agid=76054807163&f iid=&tgtid=kwd-807471796533&ntw=g&dvc=c&gclid=CjwKCAjw5vz2BRAtEiw AbcVIL4IpznzJVHkSJM0UAa4rerYc42_ibvjnkdsd_EkpKG39B sihtcQHsBoC1VcQAvD_BwE Peter Wieck Melrose Park, PA |
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#6
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Panasonic microwave, blown inverter board transformer
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#7
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Panasonic microwave, blown inverter board transformer
Doesn't change the fact that it is a source for information. Further, it suggests that it is geared towards older equipment.
Peter Wieck Melrose Park, PA |
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Panasonic microwave, blown inverter board transformer
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#9
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Panasonic microwave, blown inverter board transformer
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#10
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Panasonic microwave, blown inverter board transformer
On 15/06/2020 09:30, Cydrome Leader wrote:
What is the reliability difference, if any between the classic transfomer/diode/capacitors and the fancy inverter ovens? The Inverter model reliably makes a louder sound on expiry? I'd bet the fancy Inverter design is to get the price down, cost of copper and weight etc. The chief reason for a SMPS. -- Adrian C |
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#11
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Panasonic microwave, blown inverter board transformer
It is all in accordance with what you want.
An "inverter" microwave modulates the output of the magnetron directly. So, 50% setting means the magnetron is putting out 50% of its full capacity, but all of the time. With a conventional microwave, that is achieved by running the magnetron in duty/rest cycles. 100% for 50% of the time 0% for 50% of the time. Inverter-based microwaves become far more flexible and therefore far more useful. Re Reliability: Our present Panasonic (inverter) is about 6 years old and gets moderate use. It replaced a 16 year old multi-voltage BEAC we purchased in Saudi, that is now still in minimal use by a neighbor in his garage workshop. We keep our devices clean, make sure they get enough air circulation, and, heaven forfend, even clean the vents regularly! Basic care-and-feeding is becoming a lost art. Peter Wieck Melrose Park, PA |
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#12
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Panasonic microwave, blown inverter board transformer
On 2020/06/08 7:44 p.m., Mike S wrote:
On 6/8/2020 9:04 AM, wrote: OK. On the one hand: Purchase new Board: US$25 + shipping Install New Board: 2 hours work It all works: All good! Magnetron is bad: Purchase new Magnetron for US$65 + shipping Install new Magnetron: 2 hours work. It wall works: 4 hours + US$90 + shipping. On the other hand, a brand new 1,000 watt microwave: US$150, complete with warranty. I admire your wish to reduce landfill, but I have to wonder at the investment in a 10 year old device that is heavily used by your own description. Peter Wieck Melrose Park, PA Farberware Classic 1.1 cu. ft .1000-Watt Microwave Oven $99.99 Farberware Classic 0.9 cu. ft. 900-Watt Microwave Oven $89.99 https://www.hsn.com/shop/50-99-range...es/ho0514-6664 The question is, how long would these MWs last under the same usage as the original Panasonic? I suspect perhaps 5 years...so repairing a machine that lasted 10 years, might cost $100 - and give it another ten years. Vs. replacing it with a cheaper design that may last 1/2 the time? Is that really a better deal? Plus you have saved landfill. John :-#)# |
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#13
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Panasonic microwave, blown inverter board transformer
On Mon, 8 Jun 2020 00:02:34 +0100, Andrew wrote:
Hi, I have an NN-A554W and the transformer on the inverter board has blown. Microwave wouldn't start cooking so I ran it for a moment with the cover off, transformer did a light and smoke display and now it smells like fireworks. Impressive. I know how you feel: http://www.learnbydestroying.com/jeffl/pics/drivel/#burned-yam.jpg That's what happened when I cooked a yam (potatoe) for 16 minutes instead of 6 minutes. It was glowing bright red inside just before I opened the door. The inside of my Panasonic NN-S533WF (Sensor 1300w) microwave oven changed from white to yam colored. I tried to clean it, but the yam color is permanently baked into the paint. The S/N label says made in 2003. I think I received it as a present in 2005, making it 15 years old. It works as well today as it did in 2005 with no change in output level. That's one of the benefits of an inverter oven. I made sure the magnetron was discharged and between the two connections I am getting 0 ohms, but I only have a basic multimeter. Between those and the casing is open. Try measuring again with a much better ohmmeter or preferably an ESR meter, which will measure resistances below 1 ohm. The two terminals on the magottron are the filament wires. Less than 1 ohm is typical and is easily mistaken for a short circuit. "Magnetron Test for Opens, shorts or Insufficient Power" https://www.microwavespecialties.com/pdfs/E10-2010-06%20Mag%20Test%20Bulletin.pdf The instructions are for a commerical oven, which may have more than one magnetron inside, but the methods are the same for a home microwave oven with only one magnetron. This microwave is at least 10 years old with a lot of use, so how likely is it that the transformer has just gone by itself vs the magnetron or the small mains input board dying and taking the transformer with it? Near zero. I haven't repaired too many microwave ovens and only one inverter oven. Mostly, what I find are (in order of frequency): 1. Blown high voltage diodes. 2. Blown high voltage capacitor. 3. Blown thermal protection fuse. 4. Filthy and intermittent door interlock switch. 5. Low magentron output or dead magnetron. I would guess I've fixed about 20 mw ovens and have yet to see a blown high voltage transformer. If the enamel coating on the torroid are discoulored from overheating, you might have a problem with the transformer. If it looks normal, it's something else. You might want to try searching on YouTube for videos on how to diagnose and repair microwave ovens. This looks like a good start: https://www.youtube.com/watch?v=hBJJU4ZRh7U The other thing is that the part number of the inverter/transformer board is A6645M304GP, and the magnetron is a 2M236-M42. A lot of other models seem to use boards that look identical, but not exactly the same part number. For example I have found a site saying that this magnetron can be used with an A66454T05AP or F66454T07AP board, which do look the same as mine, so are they just a different revision or something or are the differences going to be bigger? What you're seeing are differences in part number because the manufacturer sourced their magnetron from multiple (Chinese) sources. Each source has a different part number, but are functionally and mechanically identical. The NN-A554W is a 1000 watt oven, so any 1000 watt magnetron that mechanically fits is likely to work. Even if I need exactly the same board, it looks like I could be chasing a part that would work in many different models, even different brands, if only I knew which one to look for (it seems there are no parts for my model). No parts? Google is your friend: https://www.google.com/search?q=NN-A554W+oven+parts Hmmm... are you in the UK? The Panasonic model number seems to be a UK only 230VAC oven? Am worried about replacing it and having the new one get instantly blown up though. Well, if you want an exact replacement, it would helpful if you would supply the full model number. Is it NN-A554WB or NN-A554WF ? If you have no clue what you're doing, and are lacking in basic test equipment, I would recommend: 1. Checking the magnetron with an ohms guesser. 2. If ok, replace the Hi-V diodes and Hi-V capacitor. 3. If that doesn't fix it, don't replace the magnetron. Instead by a replacement inverter board. It's one of these: https://www.kitchenwareonline.com/panasonic-microwave-oven-hv-inverter-m3ffzz000bp-c2x13938345 https://www.kitchenwareonline.com/panasonic-hv-inverter-for-microwave-ovens-z606yba00gp-c2x15619538 4. If that doesn't fix it, it MIGHT be the magnetron, but I doublt it. Magnetrons usually fade away slowly, where cooking takes longer and longer, until it doesn't cook. It does not die suddenly or belch fire. If you bought a replacement board, you've probably spend more on the repair than the oven is worth. I suggest you cut your losses and just buy a new oven. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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#14
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Panasonic microwave, blown inverter board transformer
The longevity of any given appliance is a factor. But, in one's choice of appliances, longevity is only one (1) factor. If one looks at the life-cycle cost, the factors a
a) Cost to produce, market, transport and sell. b) Cost of energy used over the life of the appliance (and, technically, the source of that energy). c) Cost of disposal when 'used up'. Then, there are wearing parts: hinges & latches, microwave safe internal finishes, bearings and so forth. Investing in repair parts might not give that further ten years. So, if one assumes that the typical microwave lasts around ten years, and is in actual use for (low end for this purpose) one full hour per week, that comes to 520 hours of operation. A magnetron tube is about 65% efficient these days. Assume all microwaves are a (mere) 700 watts. Assume the US national average cost pr KWH of $0.1331. The equation looks like this: ((700/0.65) x 520)/1,000)=560. 560 x 0.1331 = 74.536. So, it will use $74.54 in electricity in those 10 years at that rate. A modern inverter stands to use, on average, 50% less energy. So use $37 as the 'advantage' per ten years to the inverter technology. I dunno... It has been my experience that modern microwaves are largely made of parts made by robots, assembled mostly by robots, tested by robots and (maybe) visually inspected and packed by a exceedingly bored human. https://www.midea-group.com/About-Us...hen-appliances http://www.midea-gy.com/files/images/shebei/02.jpg Chances for human error are minuscule. Finishes are far better. Parts variability is far less. And so on. As cheaply made and looking as these things might feel, with proper care and feeding, there is no reason why that $89 dollar device might not last that 10 years and beyond. Fully agreed on the landfill - we are privileged that most scrap metal from our township is recycled to Acelor Mittal: https://usa.arcelormittal.com/our-op...ng/coatesville Which has been in continuous, uninterrupted operation (including wars, depressions, holidays and so forth) since 1810. It is a process. Peter Wieck Melrose Park, PA |
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#15
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Panasonic microwave, blown inverter board transformer
On 15/6/20 6:30 pm, Cydrome Leader wrote:
wrote: OK. On the one hand: Purchase new Board: US$25 + shipping Install New Board: 2 hours work It all works: All good! Magnetron is bad: Purchase new Magnetron for US$65 + shipping Install new Magnetron: 2 hours work. It wall works: 4 hours + US$90 + shipping. On the other hand, a brand new 1,000 watt microwave: US$150, complete with warranty. I admire your wish to reduce landfill, but I have to wonder at the investment in a 10 year old device that is heavily used by your own description. Peter Wieck Melrose Park, PA What is the reliability difference, if any between the classic transfomer/diode/capacitors and the fancy inverter ovens? We have a National (Panasonic) microwave from 1981, still working a treat. I know of others like it. It's pretty hard to compare MTBF when you have zero F. |
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#16
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Panasonic microwave, blown inverter board transformer
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#17
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Panasonic microwave, blown inverter board transformer
Jeff Liebermann wrote:
On Mon, 8 Jun 2020 00:02:34 +0100, Andrew wrote: Hi, I have an NN-A554W and the transformer on the inverter board has blown. Microwave wouldn't start cooking so I ran it for a moment with the cover off, transformer did a light and smoke display and now it smells like fireworks. Impressive. I know how you feel: http://www.learnbydestroying.com/jeffl/pics/drivel/#burned-yam.jpg That's what happened when I cooked a yam (potatoe) for 16 minutes instead of 6 minutes. It was glowing bright red inside just before I opened the door. The inside of my Panasonic NN-S533WF (Sensor 1300w) microwave oven changed from white to yam colored. I tried to clean it, but the yam color is permanently baked into the paint. The S/N label says made in 2003. I think I received it as a present in 2005, making it 15 years old. It works as well today as it did in 2005 with no change in output level. That's one of the benefits of an inverter oven. Lol, I've wondered about the "sensor" in these things. I know can't be related to any sort of device that measures anything. Must be marketing speak or a weirdly translated word. I made sure the magnetron was discharged and between the two connections I am getting 0 ohms, but I only have a basic multimeter. Between those and the casing is open. Try measuring again with a much better ohmmeter or preferably an ESR meter, which will measure resistances below 1 ohm. The two terminals on the magottron are the filament wires. Less than 1 ohm is typical and is easily mistaken for a short circuit. "Magnetron Test for Opens, shorts or Insufficient Power" https://www.microwavespecialties.com/pdfs/E10-2010-06%20Mag%20Test%20Bulletin.pdf The instructions are for a commerical oven, which may have more than one magnetron inside, but the methods are the same for a home microwave oven with only one magnetron. This microwave is at least 10 years old with a lot of use, so how likely is it that the transformer has just gone by itself vs the magnetron or the small mains input board dying and taking the transformer with it? Near zero. I haven't repaired too many microwave ovens and only one inverter oven. Mostly, what I find are (in order of frequency): 1. Blown high voltage diodes. 2. Blown high voltage capacitor. 3. Blown thermal protection fuse. 4. Filthy and intermittent door interlock switch. 5. Low magentron output or dead magnetron. I would guess I've fixed about 20 mw ovens and have yet to see a blown high voltage transformer. If the enamel coating on the torroid are discoulored from overheating, you might have a problem with the transformer. If it looks normal, it's something else. You might want to try searching on YouTube for videos on how to diagnose and repair microwave ovens. This looks like a good start: https://www.youtube.com/watch?v=hBJJU4ZRh7U The other thing is that the part number of the inverter/transformer board is A6645M304GP, and the magnetron is a 2M236-M42. A lot of other models seem to use boards that look identical, but not exactly the same part number. For example I have found a site saying that this magnetron can be used with an A66454T05AP or F66454T07AP board, which do look the same as mine, so are they just a different revision or something or are the differences going to be bigger? What you're seeing are differences in part number because the manufacturer sourced their magnetron from multiple (Chinese) sources. Each source has a different part number, but are functionally and mechanically identical. The NN-A554W is a 1000 watt oven, so any 1000 watt magnetron that mechanically fits is likely to work. Even if I need exactly the same board, it looks like I could be chasing a part that would work in many different models, even different brands, if only I knew which one to look for (it seems there are no parts for my model). No parts? Google is your friend: https://www.google.com/search?q=NN-A554W+oven+parts Hmmm... are you in the UK? The Panasonic model number seems to be a UK only 230VAC oven? Am worried about replacing it and having the new one get instantly blown up though. Well, if you want an exact replacement, it would helpful if you would supply the full model number. Is it NN-A554WB or NN-A554WF ? If you have no clue what you're doing, and are lacking in basic test equipment, I would recommend: 1. Checking the magnetron with an ohms guesser. 2. If ok, replace the Hi-V diodes and Hi-V capacitor. 3. If that doesn't fix it, don't replace the magnetron. Instead by a replacement inverter board. It's one of these: https://www.kitchenwareonline.com/panasonic-microwave-oven-hv-inverter-m3ffzz000bp-c2x13938345 https://www.kitchenwareonline.com/panasonic-hv-inverter-for-microwave-ovens-z606yba00gp-c2x15619538 4. If that doesn't fix it, it MIGHT be the magnetron, but I doublt it. Magnetrons usually fade away slowly, where cooking takes longer and longer, until it doesn't cook. It does not die suddenly or belch fire. If you bought a replacement board, you've probably spend more on the repair than the oven is worth. I suggest you cut your losses and just buy a new oven. I'd follow these steps too, but I also have the test equipment for doing so, but OP says they have an inverter microwave. That should scratch the #2s off the list, which is really easy for for a traditional half-doubler microwave oven. They have no way to test the HV section safely. Microwaves are truly the most dangerous electronic appliances to play with. |
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#18
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Panasonic microwave, blown inverter board transformer
Cydrome Leader wrote:
Lol, I've wondered about the "sensor" in these things. I know can't be related to any sort of device that measures anything. Must be marketing speak or a weirdly translated word. I don't think the "sensor" is a gimmick. From what I ran across somewhere, it's like a humidity or moisture measurement and really did/does work. I just had a 16~17 year old GE over-the-range type that went out that used sensor cooking and now using a $99 counter top model (1250W Magic Chef) that doesn't, I miss it. I would of replaced the GE with a current model but it's a 2 man job and with ye old pandemic, I figured the $99 special will suffice for now until an assistant is found. What's odd with the break down is the keypad doesn't work and it's not the keypad or ribbon cable. About a month before I noticed the 3-6-9 buttons wouldn't do anything but all the others were fine. Then one early morning, ComEd (local power company) cut the power for about 10 minutes which reset the clock back to the blinking 12 (actually I think it scrolls "Press clock to set time") and that was that. No more workie. It does boot, plug it in, you get the beep and even the "GE brings great things to life" scrolls on the display. Everywhere I checked for parts (figured a new/used control panel) ended up the same "Not in stock - No Longer Available". Disappointing. -bruce |
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#19
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Panasonic microwave, blown inverter board transformer
On Wed, 17 Jun 2020 06:55:26 +0000 (UTC), Cydrome Leader
wrote: Jeff Liebermann wrote: On Mon, 8 Jun 2020 00:02:34 +0100, Andrew wrote: Hi, I have an NN-A554W and the transformer on the inverter board has blown. Microwave wouldn't start cooking so I ran it for a moment with the cover off, transformer did a light and smoke display and now it smells like fireworks. Impressive. I know how you feel: http://www.learnbydestroying.com/jeffl/pics/drivel/#burned-yam.jpg That's what happened when I cooked a yam (potatoe) for 16 minutes instead of 6 minutes. It was glowing bright red inside just before I opened the door. The inside of my Panasonic NN-S533WF (Sensor 1300w) microwave oven changed from white to yam colored. I tried to clean it, but the yam color is permanently baked into the paint. The S/N label says made in 2003. I think I received it as a present in 2005, making it 15 years old. It works as well today as it did in 2005 with no change in output level. That's one of the benefits of an inverter oven. Lol, I've wondered about the "sensor" in these things. I know can't be related to any sort of device that measures anything. Must be marketing speak or a weirdly translated word. It's a humidity sensor. When whatever you're cooking gets hot enough to vaporize water, the "sensor" detects the water vapor and shuts off the oven, usually after a short delay. The alleged advantage is that you don't need to enter the cooking time or power level, but you do need to enter the type of food: https://www.youtube.com/watch?v=__tYa70kRHY I've only used the sensor feature a few times. No opinion on whether it's useful, or yet another useless feature. I'd follow these steps too, but I also have the test equipment for doing so, but OP says they have an inverter microwave. That should scratch the #2s off the list, which is really easy for for a traditional half-doubler microwave oven. They have no way to test the HV section safely. Microwaves are truly the most dangerous electronic appliances to play with. If you don't know what you're doing, don't have sufficient experience, can't follow advice, and are afraid of high voltage, perhaps you really shouldn't be fixing microwave ovens? -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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#20
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Panasonic microwave, blown inverter board transformer
wrote:
Cydrome Leader wrote: Lol, I've wondered about the "sensor" in these things. I know can't be related to any sort of device that measures anything. Must be marketing speak or a weirdly translated word. I don't think the "sensor" is a gimmick. From what I ran across somewhere, it's like a humidity or moisture measurement and really did/does work. I just had a 16~17 year old GE over-the-range type that went out that used sensor cooking and now using a $99 counter top model (1250W Magic Chef) that doesn't, I miss it. Say there is a moisture detector in ther sniffing the air being pulled from the cavity. It doesn't prevent a frozen pot pie from burning, it doesn't prevent anything from overcooking. It doesn't seem to know when a frozen sausage is transitioning from thawing to outright cooking. I really have no idea what it's doing. It's too mysterious to take seriously. Really old microwaves sometimes had the temperature probe- that made sense, assuming you were into cooking a turkey in the microwave oven for 30 minutes. Say it's real. Do the just modulate the cooing duty cycle? It doesn't seem to speed up or slow anything down, ot at least I've not found a mode that isn's still time based. What were the delicious things you could pull off with the sensor as sous chef that just don't work with the magic chef? I would of replaced the GE with a current model but it's a 2 man job and with ye old pandemic, I figured the $99 special will suffice for now until an assistant is found. What's odd with the break down is the keypad doesn't work and it's not the keypad or ribbon cable. About a month before I noticed the 3-6-9 buttons wouldn't do anything but all the others were fine. Then one early morning, ComEd (local power company) cut the power for about 10 minutes which reset the clock back to the blinking 12 (actually I think it scrolls "Press clock to set time") and that was that. No more workie. It does boot, plug it in, you get the beep and even the "GE brings great things to life" scrolls on the display. Everywhere I checked for parts (figured a new/used control panel) ended up the same "Not in stock - No Longer Available". Any parted out ones on ebay? No real need for "new" as long as it works. Disappointing. I was approached with a friend asking how to fix their above range microwave oven too. I want to help, but until they can read me the model # off the door, I can't do much with suggestions on what the next move is. -bruce |
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Panasonic microwave, blown inverter board transformer
On 18/06/2020 09:50, Jeff Liebermann wrote:
On Wed, 17 Jun 2020 06:55:26 +0000 (UTC), Cydrome Leader wrote: [...] I'd follow these steps too, but I also have the test equipment for doing so, but OP says they have an inverter microwave. That should scratch the #2s off the list, which is really easy for for a traditional half-doubler microwave oven. They have no way to test the HV section safely. Microwaves are truly the most dangerous electronic appliances to play with. If you don't know what you're doing, don't have sufficient experience, can't follow advice, and are afraid of high voltage, perhaps you really shouldn't be fixing microwave ovens? It is worthwhile pointing out, at every opportunity, that the electric shock hazard of working on microwave ovens is extreme, and that rigourous precautions are necessary. No other appliance that I can think of has the combination of high enough voltage to shock severely through clothing and dry skin, enough current to certainly kill someone, yet some current limiting and isolation from the mains such that a RCD or circuit breaker will not trip to save you. |
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#22
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Panasonic microwave, blown inverter board transformer
Jeff Liebermann wrote:
On Wed, 17 Jun 2020 06:55:26 +0000 (UTC), Cydrome Leader wrote: Jeff Liebermann wrote: On Mon, 8 Jun 2020 00:02:34 +0100, Andrew wrote: Hi, I have an NN-A554W and the transformer on the inverter board has blown. Microwave wouldn't start cooking so I ran it for a moment with the cover off, transformer did a light and smoke display and now it smells like fireworks. Impressive. I know how you feel: http://www.learnbydestroying.com/jeffl/pics/drivel/#burned-yam.jpg That's what happened when I cooked a yam (potatoe) for 16 minutes instead of 6 minutes. It was glowing bright red inside just before I opened the door. The inside of my Panasonic NN-S533WF (Sensor 1300w) microwave oven changed from white to yam colored. I tried to clean it, but the yam color is permanently baked into the paint. The S/N label says made in 2003. I think I received it as a present in 2005, making it 15 years old. It works as well today as it did in 2005 with no change in output level. That's one of the benefits of an inverter oven. Lol, I've wondered about the "sensor" in these things. I know can't be related to any sort of device that measures anything. Must be marketing speak or a weirdly translated word. It's a humidity sensor. When whatever you're cooking gets hot enough to vaporize water, the "sensor" detects the water vapor and shuts off the oven, usually after a short delay. The alleged advantage is that you don't need to enter the cooking time or power level, but you do need to enter the type of food: https://www.youtube.com/watch?v=__tYa70kRHY I've only used the sensor feature a few times. No opinion on whether it's useful, or yet another useless feature. I used it couple times years ago. It may also function when using slower cooking mode, not sure. My display gets dimmer and foggy but keeps on working. Greg I'd follow these steps too, but I also have the test equipment for doing so, but OP says they have an inverter microwave. That should scratch the #2s off the list, which is really easy for for a traditional half-doubler microwave oven. They have no way to test the HV section safely. Microwaves are truly the most dangerous electronic appliances to play with. If you don't know what you're doing, don't have sufficient experience, can't follow advice, and are afraid of high voltage, perhaps you really shouldn't be fixing microwave ovens? |
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#23
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Panasonic microwave, blown inverter board transformer
Cydrome Leader wrote:
Say there is a moisture detector in ther sniffing the air being pulled from the cavity. It doesn't prevent a frozen pot pie from burning, it doesn't prevent anything from overcooking. It doesn't seem to know when a frozen sausage is transitioning from thawing to outright cooking. I really have no idea what it's doing. It's too mysterious to take seriously. Really old microwaves sometimes had the temperature probe- that made sense, assuming you were into cooking a turkey in the microwave oven for 30 minutes. I had one of those in the shop at Clybourn, the probe had a 1/4" jack which plugged into the interior wall. Was made by Sharp. Never used the probe though. Only reason I mention it is because I bought that from a store that only sold microwave ovens. Nothing else, just microwave ovens and cookware for microwaves. Guess those died out with laserdisc stores. Say it's real. Do the just modulate the cooing duty cycle? It doesn't seem to speed up or slow anything down, ot at least I've not found a mode that isn's still time based. What were the delicious things you could pull off with the sensor as sous chef that just don't work with the magic chef? Well, I only used it for reheating leftovers. Things like yesterdays mashed potatoes or vegs (corn, peas or string beans) would come out evenly cooked (hot all the way through) and not over cooked. When I tried the mashed in the Magic Chef, I figured 2 minutes at full power would be enough being it only takes 3 minutes to cook from the fridge but no, was cold in the middle. I'm not saying the reheat mode with moisture detection is an end-all solution but it worked correctly most of the time. Several times I put something in there and it just didn't work, after 3 minutes or so it would beep with "Sensor failure" on the display panel. Then it did a 30 second countdown and end. Even things like a leftover half corned beef sandwich came out good. The sensor/reheat function just eliminated the guess work for time and duty cycle (power level). It just gets you into the ballpark. Any parted out ones on ebay? No real need for "new" as long as it works. I didn't see anything but since I'd starve around here with a microwave I didn't put a lot of effort in besides the appliance parts places on the web. Home Depot (cash and carry, no delivery schedule to mess with) basically had only 3 in stock, 2 of the Magic Chef and one Panasonic for double the price. Since I plan on replacing the overhead one at some point soon, I just didn't see a reason to spend the money on the Panasonic (although it did have a sensor). I was approached with a friend asking how to fix their above range microwave oven too. I want to help, but until they can read me the model # off the door, I can't do much with suggestions on what the next move is. If you are bored mine is a JVM1653WH01 but I don't think it's wise to put that much money into a 16 year old unit. The control board for a similar vintage dishwasher that went out a couple years ago was fetching $150 and up, used. Being I replaced the whole thing with a brand new one for a little over $300 (and no interest for 12 months), whats the point. One weird thing about that microwave which I mentioned once on chi.general, when you set the time, the first entry it wants is the month, day and year. Now being there is no advanced timer like putting in a potato and telling it to cook it this saturday at 4pm (or a year from this saturday), you figure the mm/dd/yy would be for the daylight savings switch. But no, even before they changed the dates for dst/std, it never would adjust the time by itself. Weird. -bruce |
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#24
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Panasonic microwave, blown inverter board transformer
On 18/6/20 9:50 am, Jeff Liebermann wrote:
On Wed, 17 Jun 2020 06:55:26 +0000 (UTC), Cydrome Leader wrote: Lol, I've wondered about the "sensor" in these things. I know can't be related to any sort of device that measures anything. Must be marketing speak or a weirdly translated word. It's a humidity sensor. When whatever you're cooking gets hot enough to vaporize water, the "sensor" detects the water vapor and shuts off the oven, usually after a short delay. The vapor pressure of water rises very rapidly above 60 degrees C. So presence of vapor is a good indicator of the outside temperature of your food, even before the water starts to boil. CH |
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#25
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Panasonic microwave, blown inverter board transformer
On Thu, 18 Jun 2020 23:22:57 +1000, Clifford Heath
wrote: On 18/6/20 9:50 am, Jeff Liebermann wrote: On Wed, 17 Jun 2020 06:55:26 +0000 (UTC), Cydrome Leader wrote: Lol, I've wondered about the "sensor" in these things. I know can't be related to any sort of device that measures anything. Must be marketing speak or a weirdly translated word. It's a humidity sensor. When whatever you're cooking gets hot enough to vaporize water, the "sensor" detects the water vapor and shuts off the oven, usually after a short delay. The vapor pressure of water rises very rapidly above 60 degrees C. So presence of vapor is a good indicator of the outside temperature of your food, even before the water starts to boil. CH Yep, but there's a little more to it. The 1978 Panasonic patent agrees that it's the surface temperature that's important. "Apparatus for controlling heating time utilizing humidity sensing" https://patents.google.com/patent/US4097707 See "Description" section: ...it has been known to sense the temperature of the food or degree of heating by measuring the change of humidity which takes place as the food is heated. For example, in most foods, water included therein abruptly evaporates when the temperature of the food reaches 100° C and a large amount of water vapor appears in the oven. By detecting such change of humidity by a humidity sensor, the time at which the humidity abruptly changes can be related to the time at which the food has reached 100° C. Further down the "Description" section, the patent explains how the cooking time is extrapolated from the 100° C point and the target temperature. Apparently, the humidity sensor is only interested in a single point, where the air abruptly transitions from low humidity to high humidity at 100° C. Everything else is done by temperature curve extrapolation. Crude, but effective. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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#26
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Panasonic microwave, blown inverter board transformer
Jeff Liebermann wrote:
On Thu, 18 Jun 2020 23:22:57 +1000, Clifford Heath wrote: On 18/6/20 9:50 am, Jeff Liebermann wrote: On Wed, 17 Jun 2020 06:55:26 +0000 (UTC), Cydrome Leader wrote: Lol, I've wondered about the "sensor" in these things. I know can't be related to any sort of device that measures anything. Must be marketing speak or a weirdly translated word. It's a humidity sensor. When whatever you're cooking gets hot enough to vaporize water, the "sensor" detects the water vapor and shuts off the oven, usually after a short delay. The vapor pressure of water rises very rapidly above 60 degrees C. So presence of vapor is a good indicator of the outside temperature of your food, even before the water starts to boil. CH Yep, but there's a little more to it. The 1978 Panasonic patent agrees that it's the surface temperature that's important. "Apparatus for controlling heating time utilizing humidity sensing" https://patents.google.com/patent/US4097707 See "Description" section: ...it has been known to sense the temperature of the food or degree of heating by measuring the change of humidity which takes place as the food is heated. For example, in most foods, water included therein abruptly evaporates when the temperature of the food reaches 100? C and a large amount of water vapor appears in the oven. By detecting such change of humidity by a humidity sensor, the time at which the humidity abruptly changes can be related to the time at which the food has reached 100? C. Further down the "Description" section, the patent explains how the cooking time is extrapolated from the 100? C point and the target temperature. Apparently, the humidity sensor is only interested in a single point, where the air abruptly transitions from low humidity to high humidity at 100? C. Everything else is done by temperature curve extrapolation. Crude, but effective. Hmm, sort of shocked there wasn't a "fuzzy logic" spin on all of that in 1988 or whenever that annoying as hell fad came out. |
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#27
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Panasonic microwave, blown inverter board transformer
Chris Jones wrote:
On 18/06/2020 09:50, Jeff Liebermann wrote: On Wed, 17 Jun 2020 06:55:26 +0000 (UTC), Cydrome Leader wrote: [...] I'd follow these steps too, but I also have the test equipment for doing so, but OP says they have an inverter microwave. That should scratch the #2s off the list, which is really easy for for a traditional half-doubler microwave oven. They have no way to test the HV section safely. Microwaves are truly the most dangerous electronic appliances to play with. If you don't know what you're doing, don't have sufficient experience, can't follow advice, and are afraid of high voltage, perhaps you really shouldn't be fixing microwave ovens? It is worthwhile pointing out, at every opportunity, that the electric shock hazard of working on microwave ovens is extreme, and that rigourous precautions are necessary. No other appliance that I can think of has the combination of high enough voltage to shock severely through clothing and dry skin, enough current to certainly kill someone, yet some current limiting and isolation from the mains such that a RCD or circuit breaker will not trip to save you. That's a good point too. All the service tech microwave oven deaths in the US I'm aware of were people getting dead from the capacitor, with the unit off. apparently those caps are perfectly sized to just stop your heart. You'd get noticed about who croaked last in the trade bulletin/sales "newsletters" that got mailed out every few months. No doubt if you were getting electrocuted off a running microwave, the fuse would never blow. I have a large transformer for what I'm told is an industrial microwave something device. The transformer doesn't even have shunts and outputs a full 4kV at a couple kW. It makes for one of the fiercest jacob's ladders I've thrown together. |
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#28
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Panasonic microwave, blown inverter board transformer
wrote:
Cydrome Leader wrote: Say there is a moisture detector in ther sniffing the air being pulled from the cavity. It doesn't prevent a frozen pot pie from burning, it doesn't prevent anything from overcooking. It doesn't seem to know when a frozen sausage is transitioning from thawing to outright cooking. I really have no idea what it's doing. It's too mysterious to take seriously. Really old microwaves sometimes had the temperature probe- that made sense, assuming you were into cooking a turkey in the microwave oven for 30 minutes. I had one of those in the shop at Clybourn, the probe had a 1/4" jack which plugged into the interior wall. Was made by Sharp. Never used the probe though. Only reason I mention it is because I bought that from a store that only sold microwave ovens. Nothing else, just microwave ovens and cookware for microwaves. Guess those died out with laserdisc stores. Weird. Microwaves+? I think they rebranded Batteries+ into something equally weird like batteries and CFL bulbs and +. There was one in a strip mall on Clyborn by Armitage or someting like that. Say it's real. Do the just modulate the cooing duty cycle? It doesn't seem to speed up or slow anything down, ot at least I've not found a mode that isn's still time based. What were the delicious things you could pull off with the sensor as sous chef that just don't work with the magic chef? Well, I only used it for reheating leftovers. Things like yesterdays mashed potatoes or vegs (corn, peas or string beans) would come out evenly cooked (hot all the way through) and not over cooked. When I tried the mashed in the Magic Chef, I figured 2 minutes at full power would be enough being it only takes 3 minutes to cook from the fridge but no, was cold in the middle. I'm not saying the reheat mode with moisture detection is an end-all solution but it worked correctly most of the time. Several times I put something in there and it just didn't work, after 3 minutes or so it would beep with "Sensor failure" on the display panel. Then it did a 30 second countdown and end. Even things like a leftover half corned beef sandwich came out good. Not trying to mess with you, but these sound easy enough to take care of with even random presses of the quick minute button. Going to try an "intelligent" mode for some frozen vegetables now in fact. The sensor/reheat function just eliminated the guess work for time and duty cycle (power level). It just gets you into the ballpark. Any parted out ones on ebay? No real need for "new" as long as it works. I didn't see anything but since I'd starve around here with a microwave I didn't put a lot of effort in besides the appliance parts places on the web. Home Depot (cash and carry, no delivery schedule to mess with) basically had only 3 in stock, 2 of the Magic Chef and one Panasonic for double the price. Since I plan on replacing the overhead one at some point soon, I just didn't see a reason to spend the money on the Panasonic (although it did have a sensor). I was approached with a friend asking how to fix their above range microwave oven too. I want to help, but until they can read me the model # off the door, I can't do much with suggestions on what the next move is. If you are bored mine is a JVM1653WH01 but I don't think it's wise to put that much money into a 16 year old unit. The control board for a similar vintage dishwasher that went out a couple years ago was fetching $150 and up, used. Being I replaced the whole thing with a brand new one for a little over $300 (and no interest for 12 months), whats the point. Check the prices for the "computer board" for the new washer. Probably $243 if you get a good price. One weird thing about that microwave which I mentioned once on chi.general, when you set the time, the first entry it wants is the month, day and year. Now being there is no advanced timer like putting in a potato and telling it to cook it this saturday at 4pm (or a year from this saturday), you figure the mm/dd/yy would be for the daylight savings switch. But no, even before they changed the dates for dst/std, it never would adjust the time by itself. Weird. -bruce |
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#29
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Panasonic microwave, blown inverter board transformer
On Tuesday, June 9, 2020 at 8:19:30 AM UTC-4, Peter W. wrote:
1 (800) 211-7262 I entirely understand that this Group exists so that individuals may discuss means-and-methods for doing pretty much anything at all in the hardest possible way, reaching for the least satisfactory results. And that includes reaching around the world for S.W.A.G., anecdotal experiences and arbitrary suggestions. Rather than going to the Mother Ship and asking there. Panasonic Customer Service number above. Then: https://www.justanswer.com/sip/panasonic-help-24-7?r=ppc|ga|27|Tech-CE-SQR-Search-BMM|CE-Panasonic|&JPKW=%2Bpanasonic%20%2Bengland&JPDC=S&J PST=&JPAD=378934176681&JPMT=b&JPNW=g&JPAF=txt&JPRC =1&JPCD=&JPOP=&cmpid=2032112328&agid=76054807163&f iid=&tgtid=kwd-807471796533&ntw=g&dvc=c&gclid=CjwKCAjw5vz2BRAtEiw AbcVIL4IpznzJVHkSJM0UAa4rerYc42_ibvjnkdsd_EkpKG39B sihtcQHsBoC1VcQAvD_BwE Peter Wieck Melrose Park, PA If cost is an issue, then ... I don't know if I'm just hallucinating or not, but at the end of each calendar school year, many university and college dorms have small piles of ... wait for it ... microwave ovens (amongst other gadgets) piled high outside as students are moving out for the summer. I don't exactly see armed guards surrounding those piles. |
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#30
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Panasonic microwave, blown inverter board transformer
On Monday, June 22, 2020 at 10:57:49 PM UTC-4, Cydrome Leader wrote:
Chris Jones wrote: On 18/06/2020 09:50, Jeff Liebermann wrote: On Wed, 17 Jun 2020 06:55:26 +0000 (UTC), Cydrome Leader wrote: [...] I'd follow these steps too, but I also have the test equipment for doing so, but OP says they have an inverter microwave. That should scratch the #2s off the list, which is really easy for for a traditional half-doubler microwave oven. They have no way to test the HV section safely. Microwaves are truly the most dangerous electronic appliances to play with. If you don't know what you're doing, don't have sufficient experience, can't follow advice, and are afraid of high voltage, perhaps you really shouldn't be fixing microwave ovens? It is worthwhile pointing out, at every opportunity, that the electric shock hazard of working on microwave ovens is extreme, and that rigourous precautions are necessary. No other appliance that I can think of has the combination of high enough voltage to shock severely through clothing and dry skin, enough current to certainly kill someone, yet some current limiting and isolation from the mains such that a RCD or circuit breaker will not trip to save you. That's a good point too. All the service tech microwave oven deaths in the US I'm aware of were people getting dead from the capacitor, with the unit off. apparently those caps are perfectly sized to just stop your heart. You'd get noticed about who croaked last in the trade bulletin/sales "newsletters" that got mailed out every few months. No doubt if you were getting electrocuted off a running microwave, the fuse would never blow. I have a large transformer for what I'm told is an industrial microwave something device. The transformer doesn't even have shunts and outputs a full 4kV at a couple kW. It makes for one of the fiercest jacob's ladders I've thrown together. I don't know about anywhere else in the world, but in the U.S., there's a dire warning of death with any product you buy, including a Happy Meal. Because of the fear of lawyers, every product gets warning labels no matter how sill it is, so people are now conditioned to totally ignore warnings. Pick up a can of spray paint. The instructions take up 2/3 of the can, and 9/10s of that is warnings of some type. But yes, microwaves are uniquely qualified to end someone's life. To those who don't know, microwave ovens seem less dangerous than a TV or stereo receiver, so how could they hurt someone? So, to anyone reading this that is thinking about repairing their microwave: BE CAREFUL. MORE THAN ANYTHING ELSE IN YOUR HOUSE, A MICROWAVE IS CAN KILL YOU EVEN WHEN IT'S UNPLUGGED! |
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#31
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Panasonic microwave, blown inverter board transformer
On Tuesday, February 23, 2021 at 5:35:44 PM UTC-5, wrote:
On Monday, June 22, 2020 at 10:57:49 PM UTC-4, Cydrome Leader wrote: Chris Jones wrote: On 18/06/2020 09:50, Jeff Liebermann wrote: On Wed, 17 Jun 2020 06:55:26 +0000 (UTC), Cydrome Leader wrote: [...] I'd follow these steps too, but I also have the test equipment for doing so, but OP says they have an inverter microwave. That should scratch the #2s off the list, which is really easy for for a traditional half-doubler microwave oven. They have no way to test the HV section safely. Microwaves are truly the most dangerous electronic appliances to play with. If you don't know what you're doing, don't have sufficient experience, can't follow advice, and are afraid of high voltage, perhaps you really shouldn't be fixing microwave ovens? It is worthwhile pointing out, at every opportunity, that the electric shock hazard of working on microwave ovens is extreme, and that rigourous precautions are necessary. No other appliance that I can think of has the combination of high enough voltage to shock severely through clothing and dry skin, enough current to certainly kill someone, yet some current limiting and isolation from the mains such that a RCD or circuit breaker will not trip to save you. That's a good point too. All the service tech microwave oven deaths in the US I'm aware of were people getting dead from the capacitor, with the unit off. apparently those caps are perfectly sized to just stop your heart. You'd get noticed about who croaked last in the trade bulletin/sales "newsletters" that got mailed out every few months. No doubt if you were getting electrocuted off a running microwave, the fuse would never blow. I have a large transformer for what I'm told is an industrial microwave something device. The transformer doesn't even have shunts and outputs a full 4kV at a couple kW. It makes for one of the fiercest jacob's ladders I've thrown together. I don't know about anywhere else in the world, but in the U.S., there's a dire warning of death with any product you buy, including a Happy Meal. Because of the fear of lawyers, every product gets warning labels no matter how sill it is, so people are now conditioned to totally ignore warnings. Pick up a can of spray paint. The instructions take up 2/3 of the can, and 9/10s of that is warnings of some type. But yes, microwaves are uniquely qualified to end someone's life. To those who don't know, microwave ovens seem less dangerous than a TV or stereo receiver, so how could they hurt someone? So, to anyone reading this that is thinking about repairing their microwave: BE CAREFUL. MORE THAN ANYTHING ELSE IN YOUR HOUSE, A MICROWAVE IS CAN KILL YOU EVEN WHEN IT'S UNPLUGGED! Do the insurance folk have to pay benefits if non-licensed electricians forget to bleed capacitors? |
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