Thanks man, it helped me. My microwave was dead, I opened it up and checked fuse but it had continuity. Before anything else I just cleaned and placed it back and guess what, it work fine. It just had some dust or build up around the the fuse, cleaning it helped. Thanks.
Thank you for this video. It helped me fix my NN-T795SF with a Oct 2006 build date! In my case, the primary latch NO switch had failed and was functioning as an NC switch. The button also no longer clicked. The door was not making good contact with the button due to wear, causing it to "stick" closed. The fuse would blow whenever the door was opened. Tip 1: It's a lot easier to see and work on the switches if you remove the latch assembly altogether (just disconnect harnesses and undo two screws). I found it helpful to see and understand how the door latches and release button engage the switches too. Tip 2: there's a sticker on the underside of the cover panel with the part numbers of the switches, relay and fuse. My model uses a 6x30mm 20A slow acting ceramic fuse.
Great video. I thought my microwave had just blown the fuse. But, discovered that it's primary switch had literally burnt itself out (actually melted the wire connector). Thanks to your video, I was able to replace the fuse, the switch and the connector and save myself a couple of hundred dollars! Cheers!
Its amazing how a lot of the mirowave ovens from the 1980's are still working. Specifically the one from work that i use almost every day and the one that i have at home.
The old ones had basically 4 parts. Transformer, Diode, Capacitor and Magnetron tube. Plus the interlock switches and timer of course. Inverter units are much more problematic especially the early ones from the late 90's before they figured out how to make them. The new ones are far more reliable. Many magnetrons files on the early ones too because they were being over driven.
I trash picked a Quasar Custom Touch about 20 years ago that was made in 1984. Cleaned it up and it's still working to this day. It's outlasted several newer microwaves, so I keep it around as a backup unit.
Thank You. This is a very well explained video and I was able to check the 3 limit switches and then replace the fuse. What I did find out from a different video was that the limit switch and fuse replacement part numbers (CES6) are actually written in red on top of the inside cover - this is visible as you remove the outer cover. This and the other video on the same subject by 12voltvids were very useful to also understand how to go about doing more complex repairs if one chooses to do so.
Great Video. My 7 year old Panasonic went dead recently, ready to throw out. After watching your good stuff, I opened it up and found the shorted switch. After removing the shorted microswitch I was able to make the unit work again! This will save me a few hundred dollars at least for now. Thanks a lot. I would even offer a small donation (may be $10) to your website as a token of appreciation. Please let me know.
Thank you very much for this well explained tutorial! I managed to fix my Panasonic inverter microwave by just replacing the fuse. It was more difficult mounting that microwave back up by myself than replacing the fuse that’s for sure!
Thanks for this video. My Panasonic NN-SN686S would stop after about 3 seconds. The continuity for the 3 door switches tested OK, but I noticed some electrical residue on one of the switches, so I replaced all 3 switches, which resolved the issue. The cost was $40 from the Panasonic site.
I love the concept of inverter microwaves. An inverter will be the next kind I buy. I am one of the three people who actually uses the "power" controls on microwaves. Instead of cycling the magnetron in "duty cycle" fashion, the inverter- style does it with some kind of HF PWM. Way more useful for actually reducing the heating power of the unit.
@@DrewskisBrews The big one I have in my kitchen the fan also slows when the magnetron comes on. The reason this one was so noticeable is because the cover was off. When the cover is on didn't spin down so much as it was actually working the air rather than just spinning. And no, it doesnt cool the fuse. It directs the air over the magnetron and inverter heat sink and then into the oven cavity and out the other side over the humidity sensor. When I ran it with the cover on the sound of the fan speed dropped about the same as my other one. I'm giving it away so if it blows up again oh well they got what they paid for.
Good info. I've replaced fuses before. I took the cover off our older Panasonic microwave to see if I could replace the light bulb. It has an integrated lamp assembly and I don't see any available. Now I've misplaced the screws... Microwave still works really well. I'd like to get replacement screws.
Thank you, I just fixed my inverter microwave by replacing the fuse, after checking that the switches weren't broken. I just left them in place and checked by pressing down on them. I was pretty sure it was just the fuse since the microwave stopped running during operation. The suggestion to use a small flathead screwdriver to loosen the security torx screws worked great!
i dont mean to be so offtopic but does someone know of a method to log back into an instagram account? I was stupid lost my login password. I would appreciate any tips you can offer me
@Dylan Benedict I really appreciate your reply. I found the site thru google and Im in the hacking process now. Seems to take a while so I will reply here later with my results.
My parents recently had to replace our old Panasonic Inverter from around the same time period (early 2000s). Not because of the electronics, but because the plastic door opener mechanism broke from so many years of heavy use. Not bad if you ask me, that thing must have been going on 15 years or more, having spent most of its life in a house with three kids who may not have been too gentle with it (myself included). They got a brand new Panasonic Inverter to replace the old one, and I'm expecting it'll last even longer than the original.
same thing with mine, and although im trying to get it fixed, repairing the broken white plastic bit is not stocked any longer so i dont think its worth the bother. and my time as my Panasonic is also about 20 years as well i should imagine
Thanks for sharing your expertise. It's made me pause before replacing my Panasonic NN-295. The problem is intermittent which makes trouble shooting challenging given it's an over the range model. What happens is that it will run perfectly than just stop. Power is still in the unit evidenced by the display still on when it stops. To get it up and going again it needs to be unplugged and then plugged in again and everything works fine. This happens frequently. Any thoughts or comments would be greatly appreciated.
Nice quick fix :-D I wonder if the display has one of those odd high voltage electro luminecent backlights, they do go very dim over time, i'm not impressed with them one bit.
If the security screws are in a hidden place I will just get a dremel with a thin cutting wheel and turn them all into flat head screws to take it apart.
Shorter mug next time boss... Oucha! Thanks for the vid, my little Panasonic Inverter NN-SD351M just started tripping my circuit today. Hopefully it will just be the fuse too! Cheers...
Wow, I had one of these about 5 years ago and it and couldn't figure out why it suddenly quit working. I wish I saw this video but it wasn't up yet. I bought another 1250W inverter unit at a garage sale yesterday, looked barely used and for only $40. It's manufacture date is 2016 and I hope it works a long time. It is quite a bit more powerful than my 1982 Amana radar range (which still works).
I picked up one a few years ago probably 4 years ago now in the dumpster at work or to say the recycle bin it was brand new like I'm talking brand new as in never been used I think it was pre-installed in a new house and when they first people moved in the cook didn't like Panasonic and wanted a more exotic brand so it was ripped out with the trim kit and placed on top of the recycle bin at work. I took it home works like a charm been using it ever since fantastic unit.
Thanks, I just fixed one that was being thrown out. Watched your video and then checked the main fuse and found it open. Microwave was made in 2015 and in great shape except dead (no display). Main fuse in mine was a 20A, guess the factory had too many of the 18A ones blowing out. Found a 50+ year old 20A fuse in my junk cabinet and after removing the old open 20A one, installed the 20A one from the junk cabinet. Plugged in the microwave and now had a display! Now the BIG question, did a faulty inverter or magnitron blow the fuse or did it just open due to be running too close to it's current rating? Put the power down to P5 and time at 1 minute & it warmed up a mug of water nicely. Success! Thanks for the great video. Saved me a bunch of time as I skipped the checking of the interlock switches and went directly to the main fuse after hearing you say quite a few have blown the main fuse with no apparent reason being found.
finally.. caught up on all the vids again... been busy past week lmao. this is good to know cause i have well one of these types my self. its been really good and its huge one. i think if i ended up one more size up it would been a 1250watt that's how large it is. im glad my wiring in my kitchen is done differently. since they use 3 breakers and use the 3 wire, black white and red. they split the plugs using red for one side of the plug then black for the other. then they alternate them in sets of 2. then other side is same way. so i could run a deep fryer and a microwave off the same plug but not blow anything since its 2 different loads. i don't know how they made it where 3rd breaker turns all 4 off though, that one is weird to me.
One thing that is odd about the inverter microwaves is that they don't have that single large high-voltage capacitor you see in 99.9% of videos and articles about microwave repair. Instead they have two smaller ones on the board near where the power comes into the unit. You can see one of them @10:09 in the video. It is a black blocky thing labeled 2.2 microfarads and 275 volts. I was going nuts trying to find the HV capacitor every video and article told me I had to discharge. In the end I just tested continuity on the fuse and found that was the culprit. Thanks for having a video on one of the Inverter microwaves so I don't feel like such a weirdo!
The inverter type do not have the large cap that conventional do. They use a flyback type transformer. Diodes and small hv caps. On these inverter type the frequency coming out of the transformer is very high and does not require a capacitor. The voltage is around 4200 volts dc. Unlike a conventional microwave which is either on or off, inverter types can dial down the voltage to reduce the power.
Hi my Panasonic inverter nn-sc668s just stop heating. Runs normal but I can hear intermittent clicks every few seconds. After a 2min run it shuts off after 45 secs and does not heat. Any ideas?
No definitely not. It is an 18 amp fuse, they just fail some times. The problem is the fuse holder. Heat generates between the holder and the fuse, and over time this weakens the fuse. I have seen this many times on many things, including my electric car charger.
Thanks for posting this video. Great information! I have no power. Over time, it was cutting out intermittently and then we could get it back by hitting the front and then eventually it never came back. Sometimes, the display would be dim, but it would still work. There is definitely 120v coming in to the unit and the fuse is good. The black live wire is powered all the way to the plug on the board on the back of the display (the one with the blue wire that leads to the inverter) All 3 of my switches work fine as you demonstrated...but the monitor/short switch acts strange. When the switch is unplugged, it acts as it should...shorting with the button up and clearing when pressed down. The problem is when I have the wires connected, it remains shorted whether the button is up or down (the beeping continues either way) Any idea what is causing that?
So I started to have an issue with my unit saying the door wasn’t closed. I would mess with the door switches manually (while on) and first time it ended up working. The second time I think it shorted when manually working the switches and turned off. Plugged in a new fuse and it didn’t turn back on. Could it just be one of the switches needs replacement and a fuse? Or did I make a bigger issue?
I’ve had several Panasonic microwaves (none ever failed, I only replaced due to moving overseas and then upgrading to a larger model), including a very similar one from just a tad earlier than the one in the video, and none have had fans that spin down. I wonder if perhaps the fan is failing, and that the fuse blew because the fan was unable to keep the electronics cool enough, including the fuse itself.
My family had a 1982 vintage Panasonic Dimension 3 (named as such because it offered microwave, convection, and combination microwave and convection). It wound up getting thrown out, but not before giving us over 30 years of service, though we never did use the convection oven operation, nor the combination convection/microwave. It was built like a tank, but it got to the point where it was too worn out; the turntable belt got stretched out and the magnetron became too weak to cook efficiently.
Your videos are wonderful!!! Would you have some tips for me please? The glass door of my panasonic inverter microwave oven has become very cloudy. Now I cannot see through it, and so i have no clues about the real temperature inside and how the baking is doing. I'd like to know how the dissemble the door so that I have do a thorough cleaning. Hope to hear from you!
I have opened up many a microwave oven in my time, but I cannot recall one looking like that! Usually they just have the usual transformer and capacitor set up; interesting to see an inverter.
Panasonic is I think the only company making them. They cook exceptionally well. That is why they exist. It wasn't to make them cheaper, it was to enhance the cooking.
Just purchased a brand new Panasonic (1.3) NN-SC669S (Canada). I dont think that the unit is working properly. It seems to run alright but 1 1/2 min at PL 10 with 8 oz of water and I can hold my fingers in it. I am pretty sure our old one, which was the same type of unit, heated things allot quicker than that. Does this sound right to you? Thanks
Hey, so I changed two of the door switches. but it didn't fix my problem. When I open the door the light comes on and the turn table, but not the magnatron.... any suggestions? Is it the third switch? I couldn't find a replacement easily so I only changed two switches.....
I worked as a parts subcontractor for the wiring harness for those old Amana's- built like a tank- yes, but as I recall only one interlock switch- then again maybe I recall wrong. ☺
I've got a similar Siemens HF26026EU inverter microwave that has no display. Fuse is tested and good. When I plug in the power there's no display and it won't run. If I open the door the tray motor runs. Could bad switches cause this or is the main board also bad?
Sorry about your scald. I have a [broken] panasonic microwave I am going to crack open to see what is the problem now. Thank you very much. You burn wasn't for nothing. I love fixing things.
Good work. If you can make some videos on safety? Because it may harm the inexperienced people trying to fix their devices. Specially make about handling high voltage areas in led TVs and amps. Thank you.
I had a third situation. The bottom attachment for the spring had broken off. I was able to wrap a couple of strands of picture wire around one of the black flanges and all is now good.
Jeez e-louise.... never treat a scalding like that.... i.e. do nut'n. The instant something like that happens chuck an ice pack (even a bag of frozens) on the area and leave it there for as long as possible to suck the heat out of the area and to cool down the tissue below the surface of the skin that has zero tolerance to becoming over heated.... This way you cover off any chance of a blister forming etc. Us tech guys who rely on our incomes from our hands just can't afford to smash them around like that!
I have a Panasonic Inverter and the display is dim but I can read it OK. Mine is over 20 years old now. I did have the magnetron socket short out and I actually replaced it because I like the oven. It cost under 30. It failed in storage, maybe humidity. It actually shut down with a direct short to the magnetron and did not blow a fuse.
NTP Vlogs is my channel: specializing in sharing actual repair of Panasonic inverter microwave oven, ... you share with each other to learn from each other's experience.
It uses a "flyback" type transformer to generate even higher voltages. Conventional microwave ovens operate around 2500 volts. The inverter units run closer to 4100 volts. More volts means more watts. A conventional microwave might have 700 or 800 watts, while the inverter models will put out 1250 on high power. The advantage is power control. On a conventional unit they cycle the power on and off to "lower" the power level. Basically 100% then nothing. On an inverter model, if you set it to 3, you get 30% power running 100% of the time. The defrost cycle on an inverter model actually defrosts peoperly, without starting to cook the edges. They are the best microwaves, and I would never go back to a conventional model again.
@@mrsemifixit No, they change the frequency of the oscillator for the inverter, which changes the efficiency of the transformer by moving it closer or away from resonance. Raise the frequency and the efficiency drops off which lowers the output voltage. Switch mode power supplies do the same thing. The opto coupler changes the oscillator frequency to control the voltage in the secondary.
I have this one and it seems like the initial issue you are referring to--the switches is the problem. I'm going to get another because getting a repair guy to work on it will most likely be too costly. Its not dead bc teh light still comes on when we start it. But the door has been a issue. sometimes the door will close properly and let it run and other times it does not. It has been nuanced dance of door shutting to get it to run but now it is over. You wan it?
Sometimes when you slam the door on my Panasony M O, it totally loses power, slam it again, it comes back on. It's like a loose power connection. I never opened it up. You didn't mention the HV oil filled cap, could be worse than a CRT. POP
Speaking of the secondary of a microwave. I can tell you from first hand experience don't touch it when it is operating. Threw me about 6 feet through the air.
Hi - I just got a free microwave from my neighbor, a Panasonic 800 watt, made April 2002. Do you think this is a good Microwave oven? What should I look for as far as being safe to use - ? Thanks
Sorry to inquire, I had problems with my Panasonic genius plus, I open it and check every the primary switch had a little black powder I clean and re adjust. I don’t have tools or knowledge just follow tutorials true RUclips . It works again but the fun and the lights starts on as soon you close the door, it has to open the door in order to stop this situation. I can use it normally, but if I close the door that’s happens. Do you know the issue? Also if works fixed? Is a very expensive microwave but don’t want to spend money and dealing later on with more issues, thank you!
Hi , when I start my Panasonic NN-L931BF Inverter Microwave, the timer, fan, and rotating turntable and light begin to operate but stop after exactly 5 seconds. The timer resets to start but everything else stops when the Magnetron tries to kick in. Always after 5 secs exactly. I checked all the door switches and fuses and all is OK. I'm about to pull out the Magneton Do you think this is causing the cook function to reset the oven? It is dated 2001 but I just bought it a year ago. First time this has happened. The magnetron is 2M261-M32, older than the one in your video. I don't believe the fuse is blown as it starts everytime. Do I need to replace the invertor board or the magnetron to fix this problem. Will gladly donate to you for the correct advice....Paul
Unfortunately Panasonic microwaves in the last several years have numerous quality assurance and poor reliability standards. GE is no longer making MW's, and Whirlpools are darn expensive. LG's have the keypad behind the door, and Danby's are inefficient. So what's the best 1.1 - 1.2 C.F. MW currently ?
Great video thanks. issue with my 2 year old inverter model is fuse found ok but no display. Only activity noted is If I open the door glass plate turns constantly and stops upon closing door. Everything else looks prestine inside the unit including circuit boards. Any advice appreciated cost me £250 when new!
Hi, my Panasonic model no ct878sbpq, also had a faulty micro switch, blew a trip! Replaced that, but my turntable also rotates when door open. Did you find a fix for that please. leaving mine turned seams to stop,it for a while though. Thanks.
Good units from a user perspective. I have one here but its now right down on power. 6 mins to heat 1 cup of water from 17deg C to 65 deg C. I suspect either the capacitor or diode..moreso the diode as it is heating so the magnetron is fine. I am curious to see what a magnetron stirrer looks like. They distribute the microwaves more evenly so that no turntable is needed. I wonder if they can be retrofitted.. probably not but its a thought.
It's the magnetron. They are a vacuum tube and they do get weak with age. If the diode fails you get no heat. If the capacitor failed they either go open again a no heat situation or they short and that results in a blown fuse.
A crowbar is an over voltage shut down. If a voltage goes above the set voltage of a zener diode that zener conducts and triggers an scr which puts a dead short across the power rail. There is no active components in a microwave monitor. Just a switch that closes as the door opens. The main interlock opens as the door button is pressed before the door latch is replaced. If the interlock fails to open the monitor switch will short out the mains and blow the fuse..
I have a Haier 1000 watt microwave where one of the the door switches had internally lost its mechanical integrity (I know this cause I opened it up) and just bought a normally closed and a normally open switch and replaced the faulty switch with the appropriate one ....works like a charm.
Thanks for the video. I have a Panasonic Genius Sensor 1300W inverter microwave that I rarely uses. Used like once per week. Since this morning it runs for three seconds and then shuts down. I tested the primary and secondary switches and they are fine. I disconnected the magnetron and it ran according to the timer. Once I reconnect the magnetron it stops after 3 seconds. Any suggestion?
@@12voltvids Thanks for that. I checked the magnetron and got connectivity between the two poles and none when I check the poles to the body. I figure the filament capacitor is good so I guess the issue is way in the magnetron. Thanks again. I will give and update when I get a new one sent to me in Jamaica. Not easy to find locally.
@@fffinga there will be continuity between the pins that is the filament. Remember this is a vacuum tube. Likely the seal failed and the tube has gone out of vacuum. As soon as the high voltage comes up it starts arcing internal and the power supply goes into over current protection. The 2 pins are polarized. One has the anode on it and the other the filament only. They are marked F and FA. You need to connect correctly or new magnetron will instantly burn out.
I would go by what the sticker says about power, because 1800 watts is 15 amps, so maybe the circuits plus magnatron and whatever else was on that strip, but otherwise a good find, I had one of those and I was amazed at how much lighter it was with the inverter versus a full size transformer, what it also did was ,if you use 50 percent power settings it kept the magnatron on at lower power rather than cycling on and off
I think it's a good idea to measure contact resistance of the switches and replace them if more than 1.5 ohm. the beep sound for continuity does not tell how good the switch contacts are.
Actually that's not a continuity beep. It is diode test so for a straight beep it's .2v drop or less. Above .2v drop it is a single beep as on measuring a good junction.
That's why the interlock is checked first. The plastic bracket sometimes wears out. See my video on the Kenmore microwave I did last year around this time. Bracket was worn, diagnosed it, and ordered the part, then did a second video for the part installation.
I replaced a blown 10A fuse one month ago in a 240V microwave (yes, European). It worked fine for a month, then the fuse blew again. Can't find no obvious defect. Will check the interlock. Thanks for the tip.
Hi there, I’m wondering if you could offer me some advice. I’ve watched your video and I have a panasonic nn-ct5855. Some soup blew up in there and blew the bulb. I’ve cleaned it and replaced the bulb. The microwave is still warming up food. However, there is not light and the new bulb just spins the dish in the middle when the door is open. Any ideas?
So I’m confused. You said water is bad for microwave and you put water mug to test it?? My microwave is acting weird. We have a new born and we started heating water in it to heat his milk from hot water and now the microwave sometime works and sometimes shuts off. If we wait, power cycle or hit it it starts to work and sometimes it’s doesn’t work at all. What could be the problem?
I'm coming to this party late but perhaps not so late I can't get a question answered? I have one of these inverter types which worked great up until I put it in the garage for 4 years, protected and out of weather. The time has come to use it again but I can only get it to put out 1200 watts no matter what I set it to. Do you have any feedback on fixing this? Thank you.
You know Yes, if the display does not light well look for the small electrolytic condenser you will dry over time simply change that flows the necessary power Best Regards from Frankfurt
Fuse fails yes, or the door is slammed, and the bouncing of the switch causes the shorting switch to operate and short the mains. Another thing that can blow the fuse is the lamp failing, as they typically draw a very high burst of current when the filament drops across the mains leadouts inside the glass when it dies. When buying fuses get the ones with ceramic bodies, they do not shatter like the glass ones. Very common for the fan to not run, as it is caked with dust and grease, and this eventually causes the oven to shut off after a few minutes of running as the magnetron is overheating. Clean, and put light oil on the bushes and it will work again. I have a KIC microwave made in 1984, and it still works well. Had to replace the light a few times, and eventually the magnetron got weak, so put a used one in from a later oven that rusted out. Lucky for me i live in a country with 230VAC mains, microwave fuses are 10A.
Generally when the door is slammed and the short switch contacts bounce the switch welds shorted. That is why the switches need to be checked each and every time a unit blows the fuse. On these units fuses fail after years of use just due to the springs getting weak and resistance building slightly causing heat. Seen it many times.
Hearing your story about how you got your microwave oven, I shake my head at how wasteful some people could be, throwing away a perfectly working machine. And, aaiiieee! That had to hurt. Lesson learned: don't fill a mug to the brim with water when using it as a load to test a microwave oven. Hopefully you didn't get burned, at least not too badly.
inverter versus normal transformer? whats the difference on power consumption? here in uk my old panasonic oven uses 220v 1300w ah you say 1450w at 120v interesting. wonder if would work on mains inverter off a battery?
21OCT22 Fuse blown. Ace Hardware "microwave fuse" 2ea for $6.37. Remind yourself to align both sides and top when replacing cover. Since my unit failed while running, I skipped the switch testing. I used metal polish paste, Flitz, and Q-tip to clean contacts. Smeared paste on old fuse, inserted and rotated 3x, scrubbed with Q-tip, then soft cloth. Inserted new fuse. Tested without cover. Panel light on. Check. Cup water heater for one minute, check. Replace cover and back into kitchen cubby hole. Set time: Press Time/Clock button 2x. Rotate wheel to set time. Press Time/Clock once. Ready for duty! Hopefully for another 11 years!
We had a similar model Panasonic microwave with the same power that just recently went out. The light and the timer worked fine, but it just wouldn't heat anything. There was also a bang when it was in operation when it stopped working. The microwave would attempt to heat the item for maybe 20 seconds, shut off, and give an error code that could not be cleared until the microwave was unplugged and plugged back in. We already trashed that microwave. I'm not going to worry about it now. We assumed the magnetron went out since the timer would attempt to operate it.
Could have been magnetron but the fact it went with a bang generally indicates a mosfet on the inverter blew apart. That could have been caused by a magnetron short. At that point it is a write off. Had this one had an inverter or magnetron failure it would have been trashed
@@12voltvids Mine died with a bang and some foul smoke, and it looks like the Photo SSR chip blew up. I can replace that, but I wonder if it blew up because something else shorted out too... the fuse seems fine, and nothing else looks exploded. I guess I better check the primary and secondary safety switches too, just in case, before I try to power it back up.
Looks like the thermal cutoff cut off also. (The two mechanical safety switches seem fine.) But I had a bit of trouble replacing the SSR chip and one of the pads fell off the circuit board. (The board was a bit toasted when the chip blew up) It is hard to tell what trace that pad was supposed to be attached to, and maybe it was unused. I'll try it with that pin not attached to anything and see what happens!
Yes and then some. Inverters don't have the big cap, but when energized have even higher voltages. 4100 volts as opposed to about 2100 on conventional.
My Panasonic (model NN-CT56JBBPQ, 3.5 years old) Inverter m/w combi has no display, no response of any kind with door closed BUT with mains power on, the turntable rotates with the door open. Clearly not main fuse not main door microswitch (checked). I have not checked monitor microswitch or timer microswitch (difficult for my arthritis affected fingers - so removal OK but challenge of refitting is off-putting unless there is a real prospect of it being relevant. I suspect a control panel fault giving rise to the strange malfunction. Can you help or comment please? [I have already bought a like-for-like replacement of the oven CT56JBBPQ) but I don't wish to simply throw away the faulty one - yet!]
My Panasonic NN-gd371m inverter rotating dial ( to set the mins) isn't working at all . The only thing showing on the LCD bis the 2 dots for the digital clock. iAny ideas anyone?
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Thanks man, it helped me. My microwave was dead, I opened it up and checked fuse but it had continuity. Before anything else I just cleaned and placed it back and guess what, it work fine. It just had some dust or build up around the the fuse, cleaning it helped. Thanks.
Thank you for this video. It helped me fix my NN-T795SF with a Oct 2006 build date! In my case, the primary latch NO switch had failed and was functioning as an NC switch. The button also no longer clicked. The door was not making good contact with the button due to wear, causing it to "stick" closed. The fuse would blow whenever the door was opened.
Tip 1: It's a lot easier to see and work on the switches if you remove the latch assembly altogether (just disconnect harnesses and undo two screws). I found it helpful to see and understand how the door latches and release button engage the switches too.
Tip 2: there's a sticker on the underside of the cover panel with the part numbers of the switches, relay and fuse. My model uses a 6x30mm 20A slow acting ceramic fuse.
Great video. I thought my microwave had just blown the fuse. But, discovered that it's primary switch had literally burnt itself out (actually melted the wire connector). Thanks to your video, I was able to replace the fuse, the switch and the connector and save myself a couple of hundred dollars! Cheers!
That sounds similar to my problem....
Where did you buy the parts? Would you happen to have the part numbers ?
Its amazing how a lot of the mirowave ovens from the 1980's are still working. Specifically the one from work that i use almost every day and the one that i have at home.
Yes I have a Panasonic madam grill that goes back to 87 or 88 still works.
The old ones had basically 4 parts. Transformer, Diode, Capacitor and Magnetron tube. Plus the interlock switches and timer of course.
Inverter units are much more problematic especially the early ones from the late 90's before they figured out how to make them. The new ones are far more reliable.
Many magnetrons files on the early ones too because they were being over driven.
Yes, I have a huge, third-hand, 80s one that still works, every day.
(I don't have children though...)
I trash picked a Quasar Custom Touch about 20 years ago that was made in 1984. Cleaned it up and it's still working to this day. It's outlasted several newer microwaves, so I keep it around as a backup unit.
I think the date code on mine is 1986, it's only 500W though, have to double most "regular" cooking times.
Thank You. This is a very well explained video and I was able to check the 3 limit switches and then replace the fuse. What I did find out from a different video was that the limit switch and fuse replacement part numbers (CES6) are actually written in red on top of the inside cover - this is visible as you remove the outer cover. This and the other video on the same subject by 12voltvids were very useful to also understand how to go about doing more complex repairs if one chooses to do so.
Great Video. My 7 year old Panasonic went dead recently, ready to throw out. After watching your good stuff, I opened it up and found the shorted switch. After removing the shorted microswitch I was able to make the unit work again! This will save me a few hundred dollars at least for now. Thanks a lot. I would even offer a small donation (may be $10) to your website as a token of appreciation. Please let me know.
PayPal. Volt@telus.net
Thank you very much for this well explained tutorial! I managed to fix my Panasonic inverter microwave by just replacing the fuse. It was more difficult mounting that microwave back up by myself than replacing the fuse that’s for sure!
Did you have to reset a code??
Thanks for this video. My Panasonic NN-SN686S would stop after about 3 seconds. The continuity for the 3 door switches tested OK, but I noticed some electrical residue on one of the switches, so I replaced all 3 switches, which resolved the issue. The cost was $40 from the Panasonic site.
Good job. It was detailed, informative and to the point.
Really easy to follow tutorial.
Thanks for the knowledge 👍
He mentioned not to put a cup of water without anything in it and that's exactly what he did!
I love the concept of inverter microwaves. An inverter will be the next kind I buy. I am one of the three people who actually uses the "power" controls on microwaves. Instead of cycling the magnetron in "duty cycle" fashion, the inverter- style does it with some kind of HF PWM. Way more useful for actually reducing the heating power of the unit.
Yes inverter by means of pwm will vary the hv to the magnetron and thus reduce the power. They work great.
@@12voltvids hope the skin is still attached to your hand 😳
@@DrewskisBrews
The big one I have in my kitchen the fan also slows when the magnetron comes on. The reason this one was so noticeable is because the cover was off. When the cover is on didn't spin down so much as it was actually working the air rather than just spinning. And no, it doesnt cool the fuse. It directs the air over the magnetron and inverter heat sink and then into the oven cavity and out the other side over the humidity sensor. When I ran it with the cover on the sound of the fan speed dropped about the same as my other one. I'm giving it away so if it blows up again oh well they got what they paid for.
Basically achieves the same thing and I think the older style is still more reliable
There are four of us. I find the lower power levels very useful. (But I'm also one of the few who likes fruitcake.)
Good info. I've replaced fuses before. I took the cover off our older Panasonic microwave to see if I could replace the light bulb. It has an integrated lamp assembly and I don't see any available. Now I've misplaced the screws... Microwave still works really well. I'd like to get replacement screws.
Thank you, I just fixed my inverter microwave by replacing the fuse, after checking that the switches weren't broken. I just left them in place and checked by pressing down on them. I was pretty sure it was just the fuse since the microwave stopped running during operation. The suggestion to use a small flathead screwdriver to loosen the security torx screws worked great!
i dont mean to be so offtopic but does someone know of a method to log back into an instagram account?
I was stupid lost my login password. I would appreciate any tips you can offer me
@Dylan Benedict I really appreciate your reply. I found the site thru google and Im in the hacking process now.
Seems to take a while so I will reply here later with my results.
@Dylan Benedict It did the trick and I actually got access to my account again. Im so happy:D
Thank you so much, you saved my ass :D
@Luciano Jeremy Glad I could help :D
Very informative and practical video. EXCELLENT!!!
My parents recently had to replace our old Panasonic Inverter from around the same time period (early 2000s). Not because of the electronics, but because the plastic door opener mechanism broke from so many years of heavy use. Not bad if you ask me, that thing must have been going on 15 years or more, having spent most of its life in a house with three kids who may not have been too gentle with it (myself included). They got a brand new Panasonic Inverter to replace the old one, and I'm expecting it'll last even longer than the original.
same thing with mine, and although im trying to get it fixed, repairing the broken white plastic bit is not stocked any longer so i dont think its worth the bother. and my time as my Panasonic is also about 20 years as well i should imagine
How did you go with a new Panasonic? Mine crapped itself with constant h97 errors after just a few years of light use. Absolute trash.
Thanks for sharing your expertise. It's made me pause before replacing my Panasonic NN-295. The problem is intermittent which makes trouble shooting challenging given it's an over the range model. What happens is that it will run perfectly than just stop. Power is still in the unit evidenced by the display still on when it stops. To get it up and going again it needs to be unplugged and then plugged in again and everything works fine. This happens frequently. Any thoughts or comments would be greatly appreciated.
Plse advise.. My Panasonic Microwave turn a little than STOP. I have already replaced the turn table motor. Hope to hear from you soon. Thanks.
Can you use magnetrons from other brand microwaves? ie are they all compatible?
Great vid very helpful, well explained no fluff. Just like I like it. Off to pick up a fuse. Thanks for posting :)
Nice quick fix :-D
I wonder if the display has one of those odd high voltage electro luminecent backlights, they do go very dim over time, i'm not impressed with them one bit.
I believe this one is LED backlit. Green LEDs.
If the security screws are in a hidden place I will just get a dremel with a thin cutting wheel and turn them all into flat head screws to take it apart.
Shorter mug next time boss... Oucha! Thanks for the vid, my little Panasonic Inverter NN-SD351M just started tripping my circuit today. Hopefully it will just be the fuse too! Cheers...
I did the same thing with the flat-head screwdriver 😊great video! I guess I’m on the right path already! Thanks
3:50 Mine blew the fuse as I was opening the door, so the secondary switch is a prime suspect. Thanks for posting this!
Wow, I had one of these about 5 years ago and it and couldn't figure out why it suddenly quit working. I wish I saw this video but it wasn't up yet. I bought another 1250W inverter unit at a garage sale yesterday, looked barely used and for only $40. It's manufacture date is 2016 and I hope it works a long time. It is quite a bit more powerful than my 1982 Amana radar range (which still works).
I picked up one a few years ago probably 4 years ago now in the dumpster at work or to say the recycle bin it was brand new like I'm talking brand new as in never been used I think it was pre-installed in a new house and when they first people moved in the cook didn't like Panasonic and wanted a more exotic brand so it was ripped out with the trim kit and placed on top of the recycle bin at work. I took it home works like a charm been using it ever since fantastic unit.
Great video it should go for a little while longer.
Wonder if the display voltage is low
Thanks, I just fixed one that was being thrown out.
Watched your video and then checked the main fuse and found it open.
Microwave was made in 2015 and in great shape except dead (no display).
Main fuse in mine was a 20A, guess the factory had too many of the 18A ones blowing out.
Found a 50+ year old 20A fuse in my junk cabinet and after removing the old open 20A one, installed the 20A one from the junk cabinet.
Plugged in the microwave and now had a display!
Now the BIG question, did a faulty inverter or magnitron blow the fuse or did it just open due to be running too close to it's current rating? Put the power down to P5 and time at 1 minute & it warmed up a mug of water nicely. Success!
Thanks for the great video. Saved me a bunch of time as I skipped the checking of the interlock switches and went directly to the main fuse after hearing you say quite a few have blown the main fuse with no apparent reason being found.
finally.. caught up on all the vids again... been busy past week lmao. this is good to know cause i have well one of these types my self. its been really good and its huge one. i think if i ended up one more size up it would been a 1250watt that's how large it is. im glad my wiring in my kitchen is done differently. since they use 3 breakers and use the 3 wire, black white and red. they split the plugs using red for one side of the plug then black for the other. then they alternate them in sets of 2. then other side is same way. so i could run a deep fryer and a microwave off the same plug but not blow anything since its 2 different loads. i don't know how they made it where 3rd breaker turns all 4 off though, that one is weird to me.
One thing that is odd about the inverter microwaves is that they don't have that single large high-voltage capacitor you see in 99.9% of videos and articles about microwave repair. Instead they have two smaller ones on the board near where the power comes into the unit. You can see one of them @10:09 in the video. It is a black blocky thing labeled 2.2 microfarads and 275 volts. I was going nuts trying to find the HV capacitor every video and article told me I had to discharge. In the end I just tested continuity on the fuse and found that was the culprit. Thanks for having a video on one of the Inverter microwaves so I don't feel like such a weirdo!
The inverter type do not have the large cap that conventional do. They use a flyback type transformer. Diodes and small hv caps. On these inverter type the frequency coming out of the transformer is very high and does not require a capacitor. The voltage is around 4200 volts dc. Unlike a conventional microwave which is either on or off, inverter types can dial down the voltage to reduce the power.
Hi my Panasonic inverter nn-sc668s just stop heating. Runs normal but I can hear intermittent clicks every few seconds. After a 2min run it shuts off after 45 secs and does not heat. Any ideas?
Could a failing component in the display driver circuit or its power supply have been what initially popped the fuse?
No definitely not. It is an 18 amp fuse, they just fail some times. The problem is the fuse holder. Heat generates between the holder and the fuse, and over time this weakens the fuse. I have seen this many times on many things, including my electric car charger.
I can't even find the fuse on my NN-SF564w model. & how do you get the cover back on?
Thanks for posting this video. Great information! I have no power. Over time, it was cutting out intermittently and then we could get it back by hitting the front and then eventually it never came back. Sometimes, the display would be dim, but it would still work. There is definitely 120v coming in to the unit and the fuse is good. The black live wire is powered all the way to the plug on the board on the back of the display (the one with the blue wire that leads to the inverter) All 3 of my switches work fine as you demonstrated...but the monitor/short switch acts strange. When the switch is unplugged, it acts as it should...shorting with the button up and clearing when pressed down. The problem is when I have the wires connected, it remains shorted whether the button is up or down (the beeping continues either way) Any idea what is causing that?
Hi mine has the same problem, did you get the response for the issues. Thanks for sharing
Thanks to showing us everything normally. sorry for you hand for hot water.
So I started to have an issue with my unit saying the door wasn’t closed. I would mess with the door switches manually (while on) and first time it ended up working. The second time I think it shorted when manually working the switches and turned off. Plugged in a new fuse and it didn’t turn back on. Could it just be one of the switches needs replacement and a fuse? Or did I make a bigger issue?
I’ve had several Panasonic microwaves (none ever failed, I only replaced due to moving overseas and then upgrading to a larger model), including a very similar one from just a tad earlier than the one in the video, and none have had fans that spin down. I wonder if perhaps the fan is failing, and that the fuse blew because the fan was unable to keep the electronics cool enough, including the fuse itself.
I suspect the fan slow down is due to the voltage drop on the line as the inverter comes up to full power.
My family had a 1982 vintage Panasonic Dimension 3 (named as such because it offered microwave, convection, and combination microwave and convection).
It wound up getting thrown out, but not before giving us over 30 years of service, though we never did use the convection oven operation, nor the combination convection/microwave. It was built like a tank, but it got to the point where it was too worn out; the turntable belt got stretched out and the magnetron became too weak to cook efficiently.
Your videos are wonderful!!! Would you have some tips for me please? The glass door of my panasonic inverter microwave oven has become very cloudy. Now I cannot see through it, and so i have no clues about the real temperature inside and how the baking is doing. I'd like to know how the dissemble the door so that I have do a thorough cleaning. Hope to hear from you!
I have opened up many a microwave oven in my time, but I cannot recall one looking like that! Usually they just have the usual transformer and capacitor set up; interesting to see an inverter.
Panasonic is I think the only company making them. They cook exceptionally well. That is why they exist. It wasn't to make them cheaper, it was to enhance the cooking.
@@12voltvids Indeed; pretty efficient, I should think.
Just purchased a brand new Panasonic (1.3) NN-SC669S (Canada). I dont think that the unit is working properly. It seems to run alright but 1 1/2 min at PL 10 with 8 oz of water and I can hold my fingers in it. I am pretty sure our old one, which was the same type of unit, heated things allot quicker than that. Does this sound right to you? Thanks
Hey, so I changed two of the door switches. but it didn't fix my problem. When I open the door the light comes on and the turn table, but not the magnatron.... any suggestions? Is it the third switch? I couldn't find a replacement easily so I only changed two switches.....
I find that the pins in both Torx and allen head screws break quite easily allowing the use of standard divers/bits.
They do,but my little slot driver fits in perfectly, and these screws are not driven in that tight to begin with.
Neat to see this repaired, the inside is a far cry from my 1974 Amana Radarange model RR-4D. Still in daily service and working good.
I worked as a parts subcontractor for the wiring harness for those old Amana's- built like a tank- yes, but as I recall only one interlock switch- then again maybe I recall wrong. ☺
I've got a similar Siemens HF26026EU inverter microwave that has no display. Fuse is tested and good. When I plug in the power there's no display and it won't run. If I open the door the tray motor runs. Could bad switches cause this or is the main board also bad?
Sorry about your scald. I have a [broken] panasonic microwave I am going to crack open to see what is the problem now. Thank you very much. You burn wasn't for nothing. I love fixing things.
So, being from the UK, is this the same fuse that is in the plug? Or is there another fuse within the microwave itself?
Very nice and very helpful that's awesome thanks for your help
I have a nnsd786s and its showing "SERVICE" on LCD display. Any idea what it could be?
Good work. If you can make some videos on safety? Because it may harm the inexperienced people trying to fix their devices. Specially make about handling high voltage areas in led TVs and amps. Thank you.
What do you think of Farberware vs Panasonic vs LG microwaves in the $200 and under price range as far longevity and reliability and such?
I had a third situation. The bottom attachment for the spring had broken off. I was able to wrap a couple of strands of picture wire around one of the black flanges and all is now good.
Jeez e-louise.... never treat a scalding like that.... i.e. do nut'n. The instant something like that happens chuck an ice pack (even a bag of frozens) on the area and leave it there for as long as possible to suck the heat out of the area and to cool down the tissue below the surface of the skin that has zero tolerance to becoming over heated.... This way you cover off any chance of a blister forming etc. Us tech guys who rely on our incomes from our hands just can't afford to smash them around like that!
Don't worry about me. I will survive. At least it wasn't boiling oil.
What did you do to yours where they boiled water in it how did you fix problem
Nice tidy workbench!
Looks like everybody's
I have Panasonic microwave oven ,when I’m micro power mode it’s operation for around 15 sec then it’s getting stop hearing what might be the reason
I have a Panasonic Inverter and the display is dim but I can read it OK. Mine is over 20 years old now. I did have the magnetron socket short out and I actually replaced it because I like the oven. It cost under 30. It failed in storage, maybe humidity. It actually shut down with a direct short to the magnetron and did not blow a fuse.
NTP Vlogs is my channel: specializing in sharing actual repair of Panasonic inverter microwave oven, ... you share with each other to learn from each other's experience.
so the primary switch is an open switch and secondary is a closed switch?
I never heard of an "inverter" microwave.
Does that mean it does not use a high voltage transformer? (MOV)
It uses a "flyback" type transformer to generate even higher voltages. Conventional microwave ovens operate around 2500 volts. The inverter units run closer to 4100 volts. More volts means more watts. A conventional microwave might have 700 or 800 watts, while the inverter models will put out 1250 on high power. The advantage is power control. On a conventional unit they cycle the power on and off to "lower" the power level. Basically 100% then nothing. On an inverter model, if you set it to 3, you get 30% power running 100% of the time. The defrost cycle on an inverter model actually defrosts peoperly, without starting to cook the edges. They are the best microwaves, and I would never go back to a conventional model again.
12voltvids In the inverter type instead of 100% then nothing for a duty cycle, are they using different taps of the transformer to lower the output?
@@mrsemifixit
No, they change the frequency of the oscillator for the inverter, which changes the efficiency of the transformer by moving it closer or away from resonance.
Raise the frequency and the efficiency drops off which lowers the output voltage. Switch mode power supplies do the same thing. The opto coupler changes the oscillator frequency to control the voltage in the secondary.
I have this one and it seems like the initial issue you are referring to--the switches is the problem. I'm going to get another because getting a repair guy to work on it will most likely be too costly. Its not dead bc teh light still comes on when we start it. But the door has been a issue. sometimes the door will close properly and let it run and other times it does not. It has been nuanced dance of door shutting to get it to run but now it is over. You wan it?
Thanks for the Vid. Hope your hand has healed up.
It wasn't burnt. Not even red. I get a worse burn when I am boiling belts. Hey perhaps I will keep this unit for that.
@@12voltvids That's not a bad idea at all. I think I would, that is if I had room.
Mine microwave every time I plug in power it counting P10 to P1 for two minutes then nothing works. Do you know what happen?
i bought mine used 3 years ago for about $20 and i use it multiple times every day and it's worked fantastic. so i'm not sure why they got rid of it
Any idea on how to clear a power countdown on a Panasonic NN-SN966S? It beeps, then starts a countdown from P10-P1 then 4-'s across the screen.
Sometimes when you slam the door on my Panasony M O, it totally loses power, slam it again, it comes back on.
It's like a loose power connection. I never opened it up. You didn't mention the HV oil filled cap, could be worse than a CRT. POP
No oil filled cap in this one. Inverter type, just very small ceramic caps.
Speaking of the secondary of a microwave. I can tell you from first hand experience don't touch it when it is operating. Threw me about 6 feet through the air.
You can pick up a whole set of security bits from Harbor Freight tool for just a couple bucks.
Wondering how to remove the pop out dial selector.
Hi - I just got a free microwave from my neighbor, a Panasonic 800 watt, made April 2002. Do you think this is a good Microwave oven? What should I look for as far as being safe to use - ? Thanks
Hello, I have same microwave checked all switches everything ok only problem is start and stop/reset buttons won’t work? Any idea please.
Nice video- how do I find out the size varistor to replace on a 1200 watt Panasonic unit?...
Sorry to inquire, I had problems with my Panasonic genius plus, I open it and check every the primary switch had a little black powder I clean and re adjust. I don’t have tools or knowledge just follow tutorials true RUclips . It works again but the fun and the lights starts on as soon you close the door, it has to open the door in order to stop this situation. I can use it normally, but if I close the door that’s happens. Do you know the issue? Also if works fixed? Is a very expensive microwave but don’t want to spend money and dealing later on with more issues, thank you!
Hi , when I start my Panasonic NN-L931BF Inverter Microwave, the timer, fan, and rotating turntable and light begin to operate but stop after exactly 5 seconds. The timer resets to start but everything else stops when the Magnetron tries to kick in. Always after 5 secs exactly.
I checked all the door switches and fuses and all is OK. I'm about to pull out the Magneton
Do you think this is causing the cook function to reset the oven? It is dated 2001 but I just bought it a year ago. First time this has happened. The magnetron is 2M261-M32, older than the one in your video. I don't believe the fuse is blown as it starts everytime. Do I need to replace the invertor board or the magnetron to fix this problem. Will gladly donate to you for the correct advice....Paul
My LG inverter microwave oven not hitting the food then what I m doing pls reply..
Unfortunately Panasonic microwaves in the last several years have numerous quality assurance and poor reliability standards. GE is no longer making MW's, and Whirlpools are darn expensive. LG's have the keypad behind the door, and Danby's are inefficient. So what's the best 1.1 - 1.2 C.F. MW currently ?
Could you show us how to disconnect the beeping mechanism? Thank you Kind Sir
Great video thanks. issue with my 2 year old inverter model is fuse found ok but no display. Only activity noted is If I open the door glass plate turns constantly and stops upon closing door. Everything else looks prestine inside the unit including circuit boards. Any advice appreciated cost me £250 when new!
Hi, my Panasonic model no ct878sbpq, also had a faulty micro switch, blew a trip!
Replaced that, but my turntable also rotates when door open.
Did you find a fix for that please. leaving mine turned seams to stop,it for a while though.
Thanks.
Good units from a user perspective. I have one here but its now right down on power. 6 mins to heat 1 cup of water from 17deg C to 65 deg C. I suspect either the capacitor or diode..moreso the diode as it is heating so the magnetron is fine. I am curious to see what a magnetron stirrer looks like. They distribute the microwaves more evenly so that no turntable is needed. I wonder if they can be retrofitted.. probably not but its a thought.
It's the magnetron. They are a vacuum tube and they do get weak with age. If the diode fails you get no heat. If the capacitor failed they either go open again a no heat situation or they short and that results in a blown fuse.
Isn’t the name of the type of circuit the secondary switch is part of a “crowbar” circuit?
A crowbar is an over voltage shut down. If a voltage goes above the set voltage of a zener diode that zener conducts and triggers an scr which puts a dead short across the power rail. There is no active components in a microwave monitor. Just a switch that closes as the door opens. The main interlock opens as the door button is pressed before the door latch is replaced. If the interlock fails to open the monitor switch will short out the mains and blow the fuse..
Yes, it is
I have a Haier 1000 watt microwave where one of the the door switches had internally lost its mechanical integrity (I know this cause I opened it up) and just bought a normally closed and a normally open switch and replaced the faulty switch with the appropriate one ....works like a charm.
Thanks for the video. I have a Panasonic Genius Sensor 1300W inverter microwave that I rarely uses. Used like once per week. Since this morning it runs for three seconds and then shuts down. I tested the primary and secondary switches and they are fine. I disconnected the magnetron and it ran according to the timer. Once I reconnect the magnetron it stops after 3 seconds. Any suggestion?
Ya, your magnetron is bad. Inverter went into over current shut down.
@@12voltvids Thanks for that. I checked the magnetron and got connectivity between the two poles and none when I check the poles to the body. I figure the filament capacitor is good so I guess the issue is way in the magnetron. Thanks again. I will give and update when I get a new one sent to me in Jamaica. Not easy to find locally.
@@fffinga there will be continuity between the pins that is the filament. Remember this is a vacuum tube. Likely the seal failed and the tube has gone out of vacuum. As soon as the high voltage comes up it starts arcing internal and the power supply goes into over current protection. The 2 pins are polarized. One has the anode on it and the other the filament only. They are marked F and FA. You need to connect correctly or new magnetron will instantly burn out.
@@12voltvids Thank you. A lot of us are benefiting from your advice. Keep up the great work you are doing.
My microwave (panasonic) can turn only 20 second then turn off,what is the problem you reckon? Thanks
Merci 👍🇫🇷
I would go by what the sticker says about power, because 1800 watts is 15 amps, so maybe the circuits plus magnatron and whatever else was on that strip, but otherwise a good find, I had one of those and I was amazed at how much lighter it was with the inverter versus a full size transformer, what it also did was ,if you use 50 percent power settings it kept the magnatron on at lower power rather than cycling on and off
That is the strength to these designs and the reason they exist. Power control on the magnetron.
what does a H98 fault on a microwave mean
I think it's a good idea to measure contact resistance of the switches and replace them if more than 1.5 ohm. the beep sound for continuity does not tell how good the switch contacts are.
Actually that's not a continuity beep. It is diode test so for a straight beep it's .2v drop or less. Above .2v drop it is a single beep as on measuring a good junction.
Ive seen plenty of microwaves blow the fuse because a interlock fault.
That's why the interlock is checked first. The plastic bracket sometimes wears out. See my video on the Kenmore microwave I did last year around this time. Bracket was worn, diagnosed it, and ordered the part, then did a second video for the part installation.
I replaced a blown 10A fuse one month ago in a 240V microwave (yes, European). It worked fine for a month, then the fuse blew again. Can't find no obvious defect. Will check the interlock. Thanks for the tip.
Hi there,
I’m wondering if you could offer me some advice. I’ve watched your video and I have a panasonic nn-ct5855. Some soup blew up in there and blew the bulb. I’ve cleaned it and replaced the bulb. The microwave is still warming up food. However, there is not light and the new bulb just spins the dish in the middle when the door is open. Any ideas?
I’ll happily make a donation too to your website and channel too!
How can fix H97 problem for Panasonic microwave oven NN-CD997S model?
plz help me
So I’m confused. You said water is bad for microwave and you put water mug to test it??
My microwave is acting weird. We have a new born and we started heating water in it to heat his milk from hot water and now the microwave sometime works and sometimes shuts off. If we wait, power cycle or hit it it starts to work and sometimes it’s doesn’t work at all. What could be the problem?
I never said water is bad for a microwave. A microwave needs a load to absorb the microwaves. Water is a perfect load.
I'm coming to this party late but perhaps not so late I can't get a question answered?
I have one of these inverter types which worked great up until I put it in the garage for 4 years, protected and out of weather. The time has come to use it again but I can only get it to put out 1200 watts no matter what I set it to.
Do you have any feedback on fixing this?
Thank you.
Haven't a clue.
Nice video, all useful. That 15A that tripped, what voltage? 110/220? (I'm in UK, we only have 220 in houses.)
That one running 120. We have both 120 and 240 here but small appliances like microwave run 120
You know Yes, if the display does not light well look for the small electrolytic condenser you will dry over time simply change that flows the necessary power Best Regards from Frankfurt
Fuse fails yes, or the door is slammed, and the bouncing of the switch causes the shorting switch to operate and short the mains. Another thing that can blow the fuse is the lamp failing, as they typically draw a very high burst of current when the filament drops across the mains leadouts inside the glass when it dies. When buying fuses get the ones with ceramic bodies, they do not shatter like the glass ones. Very common for the fan to not run, as it is caked with dust and grease, and this eventually causes the oven to shut off after a few minutes of running as the magnetron is overheating. Clean, and put light oil on the bushes and it will work again.
I have a KIC microwave made in 1984, and it still works well. Had to replace the light a few times, and eventually the magnetron got weak, so put a used one in from a later oven that rusted out. Lucky for me i live in a country with 230VAC mains, microwave fuses are 10A.
Yeah magnatrons are easily replaceable ,and just troubleshoot the inverter board ...dam its just a smps power supply jacked up
Generally when the door is slammed and the short switch contacts bounce the switch welds shorted. That is why the switches need to be checked each and every time a unit blows the fuse. On these units fuses fail after years of use just due to the springs getting weak and resistance building slightly causing heat. Seen it many times.
Hearing your story about how you got your microwave oven, I shake my head at how wasteful some people could be, throwing away a perfectly working machine.
And, aaiiieee! That had to hurt. Lesson learned: don't fill a mug to the brim with water when using it as a load to test a microwave oven. Hopefully you didn't get burned, at least not too badly.
Great videos, detailed and understandable, thanks.
Or use the device called a handle.
@@chazdesimone7306 You can still spill the water if you don't take the mug out of the oven carefully.
inverter versus normal transformer? whats the difference on power consumption? here in uk my old panasonic oven uses 220v 1300w ah you say 1450w at 120v interesting. wonder if would work on mains inverter off a battery?
It depends on power output. Conventional topped out at around 800 watts and inverter models up to 1200 watts.
21OCT22 Fuse blown. Ace Hardware "microwave fuse" 2ea for $6.37. Remind yourself to align both sides and top when replacing cover. Since my unit failed while running, I skipped the switch testing. I used metal polish paste, Flitz, and Q-tip to clean contacts. Smeared paste on old fuse, inserted and rotated 3x, scrubbed with Q-tip, then soft cloth. Inserted new fuse. Tested without cover. Panel light on. Check. Cup water heater for one minute, check. Replace cover and back into kitchen cubby hole. Set time: Press Time/Clock button 2x. Rotate wheel to set time. Press Time/Clock once. Ready for duty! Hopefully for another 11 years!
We had a similar model Panasonic microwave with the same power that just recently went out. The light and the timer worked fine, but it just wouldn't heat anything. There was also a bang when it was in operation when it stopped working. The microwave would attempt to heat the item for maybe 20 seconds, shut off, and give an error code that could not be cleared until the microwave was unplugged and plugged back in. We already trashed that microwave. I'm not going to worry about it now. We assumed the magnetron went out since the timer would attempt to operate it.
Could have been magnetron but the fact it went with a bang generally indicates a mosfet on the inverter blew apart. That could have been caused by a magnetron short. At that point it is a write off. Had this one had an inverter or magnetron failure it would have been trashed
@@12voltvids Mine died with a bang and some foul smoke, and it looks like the Photo SSR chip blew up. I can replace that, but I wonder if it blew up because something else shorted out too... the fuse seems fine, and nothing else looks exploded. I guess I better check the primary and secondary safety switches too, just in case, before I try to power it back up.
Looks like the thermal cutoff cut off also. (The two mechanical safety switches seem fine.) But I had a bit of trouble replacing the SSR chip and one of the pads fell off the circuit board. (The board was a bit toasted when the chip blew up) It is hard to tell what trace that pad was supposed to be attached to, and maybe it was unused. I'll try it with that pin not attached to anything and see what happens!
There’s no security measures when you open an Inverter microwave as the ones taken in a regular microwave regarding capacitors?
Yes and then some. Inverters don't have the big cap, but when energized have even higher voltages. 4100 volts as opposed to about 2100 on conventional.
Quite often the door switches will show continuity when testing but are actually bad. On load it will fail
My Panasonic (model NN-CT56JBBPQ, 3.5 years old) Inverter m/w combi has no display, no response of any kind with door closed BUT with mains power on, the turntable rotates with the door open. Clearly not main fuse not main door microswitch (checked). I have not checked monitor microswitch or timer microswitch (difficult for my arthritis affected fingers - so removal OK but challenge of refitting is off-putting unless there is a real prospect of it being relevant. I suspect a control panel fault giving rise to the strange malfunction. Can you help or comment please? [I have already bought a like-for-like replacement of the oven CT56JBBPQ) but I don't wish to simply throw away the faulty one - yet!]
My Panasonic NN-gd371m inverter rotating dial ( to set the mins) isn't working at all . The only thing showing on the LCD bis the 2 dots for the digital clock. iAny ideas anyone?