Great instructional video, a true professor of electrical / electronic mix technology. Thank you for sharing your knowledge and skills with the rest of us that enjoy understanding rather than just tossing, when something simple seems to be possibly fixable. I'm from the mighty USA, as you are from the mighty Canada, both are awesome countries with knowledge abounding forward. Brilliance comes with willing effort. May peace and great success be with you always. A brother in life, no doubt. ; )
Very helpful video. I opened the case on mine and noticed 2 wires (orange and black) had melted off the connection. All fixed and works like a charm. Most expensive coffee warmer upper haha
Thank you for this great video. You obviously work very well and know what you are doing. I'll be sure to save this video and your channel in my lifelong references.
Thanks so much for the video. My last microwave lasted me 10 years and was a hand me down from my mother. a Samsung probably 15 years old, still works but the wife wanted stainless steel. The expression "they don't make 'em like they used too" really applies.
A nice primer on the insides of my Panasonic Inverter MW. About 9 years old it was beginning to start-stop-start in mid-operation which I correctly surmised as an intermittent connection. I used a small flat head precision driver to remove those 4 Torx anti-tamper screws plus one Philips head on the right side of the case. Sure enough the primary micro switch showed heat damage due to the failing contact. I got a V-15G-3C25K on order. Thanks for your expertise and floating camera work.
UPDATE: Got the switch from Mouser. The connector lugs were damaged from the arching of the bad switch and had to be replaced. The new switch would not snap into place because of the mounting post wouldn't fit into the switch's hole. I drilled the hole one millimeter larger and it finally fit. The oven works like new. Parts: $3, Shipping: $8, My labor: $100, Aggravation charge: $200. Green Points: 10 (for not adding to the dead appliance dump).
Great video, thanks for sharing it. Years ago I repaired our Kenmore microwave, it was an easy fix (the door micro switch was shot) Apparently if you open the door while the microwave is doing its thing it creates an arc across the contacts and after a few times doing that the switch no longer works. I was told by a neighbor and friend that if you want to avoid damage to the door micro switch you have to turn off the power (by pressing the stop/pause button first) before opening the door. My question for you is this... Two years ago I bought one of the newer microwaves that you showed at the beginning of the video and in the past week or so it has started to intermittently turn off while operating. If we closed the door hard it would sometimes work but when it turned off the turntable motor continuously turned. Yesterday I decided to take it apart and try to see if there was a loose connection inside or maybe a bad ground. After taking the cover off I wiggled many of the wire connections and checked for any burnt wires but I didn't see any. After that I took out the micro switch on the door and it seems to work fine. After putting it all back together the thing doesn't even power up the display. The funny thing is the motor which turns the turntable inside is always on from the second you plug it in but no display, nothing. Any idea what might be causing this?
@Metalcastr These definitely heat fast, but they do have continuously variable power down to 40%, unlike the pulsed mode that normal microwaves run. No one seems to use the proper gauge wire anymore, especially in white goods. The profit margins are just too small to use any quality parts. The big players seem to be able to push UL or ETL into allowing them to do things smaller guys wouldn't be allowed to do, like drawing 17A from a 15A circuit or running 17A through such thin wire.
@Garcansdad Yes, that's a lot of current for a microswitch. It may very well be the microswitch dying, not the faston. I've got some NSTs, a 15/60, 12/60 and a 12/30. Never heard of a 30kV one, 15kV is the highest I've seen. I've heard of (but never seen) a legendary 15kV 120mA NST, but they're very rare.
@ubuntupokemoninc Not quite, there's a 3rd switch that tells the control board to turn on the inverter, so all 3 switches would have to fail in just the right way for it to run with the door open.
It is common for those film caps to make noise. It isn't easily heard though unless they're up near ear level like that. It's very common in computer power supplies, but usually covered up by the fan noise.
I understand an additional ohm check on a Magnetron is to check the terminals individually to the outside casing of the Magnetron. They sometimes short at the terminals.
Hi, for the first machine you fix in this video, that switch you replace--the one connected to the door opening device--what is the part number for that and where can I order one? Thanks!
As a qualified electronics engineer with forty years of repairing products and 30 years of microwave repairs trained by Sharp and others I am horrified that you have not mentioned how accidental contact with the high voltage areas around the magnetron can easily prove lethal. These appliances were repaired by a company I used to work for and a colleague (Television Engineer) used to debate with me how a high voltage shock would hurt but not do any more damage when I warned him about working on live units. He was used to accidentally receiving shocks from CRT screens of 25 000 volts but only a few Milli amps that would sting. Our training always told us to Disconnect before repair, open the door so no chance of powering up (should we have failed to disconnect) and Discharge any High voltage left that had not been bled away from the magnetron. My colleague was complacent and ignored this and was found dead in our company's workshop in 1995 when he had worked through his tea break and accidentally touched a working microwave, I know there is a lot of safety warnings that anybody with a little knowledge tends to ignore but when you are putting up a video that actually encourages others to work in such a high danger area without any warnings I find it very responsible..
I completely agree with you. I am also a qualified tech, but even before I was qualified I did factory training with Sharp 30 years ago. When we walked into class on the first day, "MICROWAVE OVENS KILL TECHNICIANS" was written across the blackboard. 2 guys walked out never to return. The instructor certainly had the full attention of those of us remaining. This video like many others like it, is reckless. I hope nobody having viewed this has hurt themselves or heaven forbid, died as a result. I've put in my suggestion to youtube that it be removed.
Nobody not familiar with electricity should be working on anything electrical! That is a given in most peoples eyes. I do believe that he is trying to help us that do know that these things are dangerous and do know how to implement safety precautions. So... Get your head out of your engineers ass and help us out here!!!
So how do I ask you the questions I have on my micro? You seem to have experience with these and the one I have is pretty much the same as whats shown on these vids but bigger. Would you reply to my questions on this comment page of his? I need to know whats going on with this...thank you for replying back to me though We that do know electricity need real help.
Great instructional video! Thanks! I have an NN-C994S and it has been working fine for 10 years. It recently started blowing the power strip I have it plugged into and I have had to reset it about 3 times in the last 6 months. Most recently, it started turning off 5 secs into a heating cycle. Now this just has to do with the microwave. The convection operation works fine which is why I am hesitant to just ditch it. I took the shell off and looked at switches in the door and nothing seemed burned. So, experimenting, I disconnected one of the connections to the magnetron and ran the unit. It shut off again but went about 10 seconds. I disconnected both leads to the magnetron and ran the unit and again, ran about 10 seconds and shut off. Then I plugged both leads back into the magnetron and ran the unit again and something close to the heat sink looking part on the Inverter board started arcing and the inverter burned pretty bad. No fuses blew and i turned everything off immediately. Is it safe to say the Inverter needs to be replaced? Is it worth the cost of the inverter? or could the magnetron still be the problem? I am at a loss as to how to proceed and like I said, hate to pitch it since the convection function still works and the combo is hard to find! Thanks for your guidance.
I found this video very informative. I worry about people with no electrical/electronics background working on these machines. I don't know why so many people have asked questions. The author of this video like most obviously doesn't have the time to answer everyone's queries about a myriad of fault conditions. This must be one of the most dangerous items to be found in a domestic environment for the unwary diy fixer.
I've seen burnt connectors (underrated for the current) way more than I can remember. The built up heat then has caused all kinds of different problems. I think most common has been on a regular oven the main over heating protector to fail because the bad contact burned the whole protector. After changing the (spade?) connectors I use pliers to tighten them even more. Manufactures tend to use those connectors that have lock mechanism so that the connectors don't disconnect from vibrations. But the problem is then that the connector itself is loose and cannot carry the current propely and thus heating up. I guess it faster to assemble appliances that have loose connectors with lock mechanism than to use a bit more force to push in a stiff (proper) connector. Those loose connectors with locks are worst when used with magnetron. The ~3V heating current is quite high...
Hey I have the exact model in the video on the first two. The settings and everything work. I just can't seem to hit the start button after setting to the desired time. What should I do?
18 gauge wire can handle up to 28A depending upon the insulation. UL / ETL has lower limits depending upon the class of device and its function. Residential and commercial electrical codes for building purposes derate things even further. Alas, these are the only the specs on the wire. In this case, the problem is likely to be hot spots with the crimped faston causing the microswitch to fail prematurely. Die wear, alignment, and pressure variation at the factory can all contribute to a crimp not meeting manufacturers current ratings. In addition, had that faston been replaced in the field at some point, its a real pig in a poke, as most hand tools do a pretty poor job at making crimps capable of handling that level of current. I learned this the hard way as a n00b engineer many years ago... A semitrailor full of rejected units due to harness failures leaves a lasting impression. Thanks for the video, now I know exactly what to look for. I may end up replacing that wire in my Panasonic with something far more robust to prevent a future failure.
@filipkof I'll try drawing some arcs off one of these inverters. I have no idea what it'll do, but I know the inverter will survive a short circuit, so there's a chance it'll work. On a 15A breaker, typically you can draw about 17-18A continuously on a good (new) one, and perhaps 30A for 5-10 seconds or so.
I would really appreciate your advice. I have easily repaired dead microwaves over the years just by replacing the micro switches on the door latches, and one by replacing the magnetron, but after a month of tinkering with my Model NN-H965wfx Panasonic Inverter microwave, I am stumped. The fuse, thermostat, and all three door switches work perfectly. I tested the switches both in and out of the microwave to ensure the latch was actuating the switches correctly. I get power through the fuse, but there are no signs of life anywhere else. The display and interior light do not light up and the microwave is totally dead. As it began to fail this microwave would randomly power off like it was unplugged, and come on when you bumped the front side near the control panel. Over a period of a few days, it required more bumping till it just quit altogether. I thought it was just a door switch, but they all tested as good. What else could totally kill all power to the microwave? I am not a repairman or electrician, but I do have a micrometer and am determined to learn what is wrong. Any help would be appreciated.
The problem is popping the door latch before the microwave has timed out. You are therefore opening the door interlock microswitch under load causing sparking and overheating which extends out the switch to the connected wiring. You did exactly that in your test of the repaired unit. Use the stop or wait until timed out.
I just learned this 2 weeks ago when trying to find out why my 6 year old Panasonic would only run for a couple of seconds. I've been doing it wrong for 30 years. Old habits are hard to break. LOL
I have a newer one of these [Panasonic [NN-T6648FX], got a Code 98. Fuse is fine. I checked the continuity on the Magnatron, have continuity between the leads, but also have continuity between the each lead and ground (this seems odd to me). Does this mean the Magnatron is bad? I looked at the manual but could not exactly figure out how to check the volts at the Inverter connectors CN702 (120v AC) and CN701 (3v AC) Also the manual says to press CLOCK TIME START POWER LEVEL to test. When I do this displays 88.90 (I think) but testing at the leads unplugged from the board I get no AC reading. So, what I really want to know is it the Magnatron, or the Inverter circuit that's bad. I want to get the diagnostics right first, then order the part. Thanks for any help you can provide! Thanks for your videos!
Hi there, My microwave similar to these trips the circuit breaker in the house when I open the door. The door switches(3) all seem good. If I remove the earth wire nothing is tripped and all appears good.I tried using the garage outlet as it has a different breaker. When I do and I open the door the fan starts as well as the carousel motor and nothing trips. Any ideas?
Rickmoses: This was my problem too, but after watching this video and seeing that the current is too high for the door switch design, as soon as I opened my unit up and saw a burned connector to the very same switch Telsa500 showed us how to fix, I was convinced the burned connector was limiting current flow and that is why the unit was shutting down. That the switch was still working is why the unit operates for a little while before shutting down. I opted to repair the connector by soldering
Hi. I have an NN-ST761SF that runs for exactly 23sec whatever time you set. If you stop it after 10 or 20sec by opening the door, it runs for another 23sec! There is no heat at all. All 3 door switches appear fine - though one is N/C and 2 are N/O... I don't have a wiring diagram but presume that's normal. Any ideas?
5 years ago I bought Kenmore's best microwave. 13 months later, smoke started coming out of the the top vent and you could hear it was loaded up, pulling a lot of amps. Found a couple of loose spade connectors at the high voltage diode and the diode checked as being shorted. $15 replaced the high voltage diode and the cap it was connected to. Everything was back to normal. I don't know the differences between types, does this sound like an inverter microwave and what are the differences?
My photo electric smoke alarm had a false alarm the day before my inverter microwave quit. After watching your video, i guess it wasn't a false alarm after all. Same thing happened with my furnace a few years ago. It triggered an alarm and i thought it was a false alarm. Gotta learn to believe the alarm.
Thanks for the video! I have a Panasonic Inverter Microwave and hope you can help figure my problem. The microwave plugs in and lights up, when I push a minute and start, the LED light turns off, but screen is on. Interior light turns on, but microwave doesn't start. Buttons still make sounds and work. Any ideas and advice?
I have one similar to the first one you posted. I checked switches, megnetron, thermal switch, everything are good. But when I press START, no action, no sound, no fan, no light. Do you think it is the START button goes wrong or other issue ? Thank you .
Hi Tesla500, I have microwave inverter nn-cf770m just two years, and it just suddenly stop working. Led is still on. when started it 1st run for 30' and stop. After few times like that, when started it turn off one of the the Isolator switch of the house. Do you have any suggestion on the cause.
Good post - thank you! I'd be more concerned about the integrity of the spade connector rather than the wire itself. The contact area is minimal even when they are tight and in good condition. If they are slightly loose, the end result will eventually be the failure that you illustrate.
NTP Vlogs are my channel. I share the reality. repairing Panasonic inverter.cho microwave oven You learn from each other's experience. A reference channel is very useful.
I am replacing my Panasonic NN-SA651S Inverter board. I forgot the mark the wire. I don't have problem this wires yellow, Brown and Orange, cos the it can only poke in one way, next I have this White and 2 brown wires, this I can plug in either way. I want to know is the White I believe is (Neutural) face outer side of the board and the remaining two Brown wires are face inside OR it can be on either side. Lastly the Two Red wires connect to the Magnetron from the Power can it be connect to either side? Thank you and hope to hear from you soon.
I have a Panasonic Inverter Microwave that trips the breaker at the end of the cooking when the timer is done and the microwave switches off. Where do you think the problem is? If I pull the plug out before the timer is done then the breaker does not trip
Question is at the end of this You spoke of electronics safe cleaner . I have one, however customer left plastic container for 10 min, container liquidized and made a light orange film all over inside of oven, a very horrid smell like burnt popcorn x100, I managed to remove it (hours ) with a solvent. However the electronics area including inverter board still has it . I cleaned the fan , the sensor etc. Question you mention a electronic safe cleaning spray, what spray would you recommend? Needed a solvent inside the oven as a thin layer of plastic was causing the white inside to appear yellow.
My micro failed earlier this week. Was gonna open it and see if it was just a fuse, but decided against it. Just brought a new unit. I wanted to try an inverter type, but *people* just got to have a "pretty blue display" ugh.
Hi my national microwave oven convection inverter type has an issue as soon as the start button is on the fuse gets blown out could u suggest an solution to this thanks
Very interesting and well presented. I have a NN-ST657S which the microwave is still working but the turntable and light suddenly went off. I checked the fuse which is still OK - nothing looks untoward - Only about 2 years old
yep I think it might be normal the buzzing I have a red Mainstays (not an inverter) that also does the same thing I think it might be coming from one of the small transformers on one of the controle boards. Those tend to get noisy.
I've a Panasonic microwave Model number NN-A574SBBTQ about 6 years old and 2 years ago the bulb stopped working. Today I tested the continuity of the spade connections to make sure power was applied when the door was open... I figured the bulb was faulty. Anyway my multi meter accidentally touched together the spade connections of the bulb and this has now caused the microwave to blow. No power to it st all. It tripped out at the Mains, I checked the plug fuse which was ok, along with the 10amp and 16amp fuse inside the microwave. All ok but no display coming on microwave. Any idea what might be the issue?
I have an Panasonic Inverter combination oven. After setting a program, the oven starts working then immediately switches off ( issue with all programs, whether on Microwave or Oven mode).. Any idea what the problem might be?
What can I do mine the door springs in and slowly pops back out, and when setting the timer nothing happens also it goes back to clock display.we give it a couple of bangs and we might get lucky and it starts.its the same model Panasonic inverter you are working on now.Help please thank you 🙏🏼
Hi i have an issue with my national convection inverter microwave as soon as the start button is started the fuse get blown out could u advice me with a suitable solution thanks
That noise that you hear from the filter circuit is cause my hi frequency noise on the AC line. If you where to plug a lamp with a dimmer in the same outlet that your microwave is plug into and dim the lamp, You will really hear is buzz from the triac noise cause by the dimmer.
so the new microwave inverters dont have stored charge ? i have 1 of them but waiting to see if it is safe to take apart for parts its been unplugged for about a week ?
I have a similar full size panasonic inverter microwave NN-L931BF built in December 2001. There is no light or anything on when plugged in. It was used regularly and was functioning properly during the last use. The power filter and inverter are on the same board for mine unit. Both buss ABC18A and temperature fuse are good. Do you have any suggestion for where to look afterwards? I am a novice but always interested in fixing everything in the house. Thanks. Gary
Nice tutorial. I can't believe they are running that much current through a microswitch. Along the lines of high voltage transformers - have you used any old school neon transformers? They used to sell units with 30Kv output at 60 Ma. They made great Jacob's ladders.
Hi, any help you can give me would be great thanks. I was wonder what can be wrong with my panasonic inverter microwave 1250. Every time you go and push the start button, it will reset. The microwave wont allow me to hit the start button. Everything goes blank like if I were to push the reset button. Thanks in advance
Hi, Have you ever modified the Panasonic Microwave so that there is no 10 Seconds delay before full power is emitted ? I am trying to reduce the time to get it to start cooking right away (or close to it) at max power.
13:44 It is called *piezoelectric effect.* And generally is more noticeable with ceramic capacitors. If ceramic caps are used in sensitive circuits such as audio amplification stages, they can also pickup vibrations on the PCB, just like a microphone.
There isn't 17 amps going through a 18 awg wire. The problem is popping the door latch before the microwave has timed out. You are therefore opening the door interlock microswitch under load causing sparking and overheating which extends out the switch to the connected wiring. You did exactly that in your test of the repaired unit. Use the stop or wait until timed out.
G’day Tesla500. I don’t know if you still monitor this post but if you do..... My Panasonic NNCD987W Dimension4 microwave runs for exactly 1 minute at any setting then restarts with the “Welcome” message. If I set the timer for less than a minute it finishes correctly with the “Enjoy your meal” message. The machine is 7 years old but looks as good as new. Do you have any advice as to the problem, can I replace or adjust something to fix it? Your assistance will be greatly appreciated. Cheers, Bazza.
I have a nn-sd978s panasonic microwave it worked great for years, then it started to smell burnt, and stopped working replaced the fuse and worked before we saw that the power supply connection had melted. Does anyone know where I can get a replacement psu board and the actual power cord. Can't find one for my microwave
Impressive, have had the same model for over 7 yrs. no problems except for that control knob. Is that part of a sub control board or is a single control board? My control knob turns of course, but no longer will allow me to set any parameters any thoughts, and where can I pick these parts up??? Great video.
Interesting, I had no idea they even made inverter microwaves - maybe I should dig through some next time I go to the junkyard. They look pretty flimsy though, I imagine they're a lot more prone to failure versus a plain ol laminated iron and copper transformer.
Hi Tesla. I want to ask you for help... My MW Model NN - T695SFX has this problem... After I put over 30 Secs on the clock and press Start, around 30 - 40 Secs it stops and on the screen shows H98 .. Only that. And it's not heating anything at all... I'd like your thoughts... Even better if you show us how to fix it since there's more people with this same problem... Thanks in advance.
The error codes H97, H98, and H99 are used to indicate problems related to the inverter circuit and the magnetron. These codes appear on the display window after the start key is pressed and there is no microwave oscillation. Check for magnetron filament continuity.
What causes the startup "squeal" or "screech" heard at 11:24 and 13:33? Is this a component of the inverter going bad, or a failing magnetron (inverter can't supply enough initial power)? This is a common symptom of many Panny inverter microwaves, but I haven't found the answer yet. Anyone?
Good video, troubleshooting... I recovered many uwaves when they were worth something - still have one old Amana - first of the consumer real stainless Inside too) when they were $900 in the 70s. Once my son called me "Dad the new microwave in the office brought down the power - they are throwing it out - do you want it?" I stiil have that one :) I too hate to see the stuff go to "recycling" which is mostly just metal recovery. Have one Panasonic inverter in the kitchen, likely 2nd gen. I then bought an clean older one for the cabin for $12 and it flaked a bit , blowing fuses. I thought it was the crowbar switch but no. After your vid I took another look as I had assumed it was the inverter. Guess what? Magnetron was 220 Ohms filament to ground :{ Problem fixing them is room for that stack of carcasses! So I said nuts and scored a rarer white one (NNST651W) cyber Monday Bbuy $99. We will see how it does. Cheers
I have a panasonic sd277wr. It is about a year old. starting about a month ago some times when I press start it only turns on for about 1 second and then stops. I try again and it does the same thing. I have pressed about every button I can, I removed the power from the wall and it still happens. I disabled the turntable but no luck. Eventually it will start working just like normal. It may work for a week without problems but then it will do this again. What could be wrong?
I have a question: Do all microwaves use rotor blade fans (which we see in this video) as opposed to squirrel wheel blowers, the types found in stove exhaust vents? Blower wheel fans tend to be much more powerful; Have you come across any microwave ovens that use them?
Maybe you can help me, i have my mothers old NN-S577WC 1997 microwave, it heats but the light, the blower motor and the rotissorri motor does not spin,( although it works with 110 volts when disconnected hooked up to the wall socket ) i smell a burnt electrical smell but dont see anything but guessing from where the wires come from the main board to the blower and rottisorri motor i guess there is a problem in the main board, everything elseworks fine, even the srolling messages on the screen,
@ihatespam1977 It is unfortunate that good old iron and copper transformers are being pushed out of the market. They're very reliable, and good for experimenters. But if the inverters take over completely, I'm sure people will find ways to make use of them for HV experiments.
How can you manually turn on the inverter? When I shut my door, the screen turns off and it automatically spins the table for a few seconds and then everything turns off... I'm assuming something is wrong with the boards... I crossed the power wires on the board (blue and black) to bypass that relay.. and (while the display is off, because the door is shut) the table turns, and the fan runs... but it doesn't heat.... It still shuts off when I open the door (so that's good). I'm assuming the three smaller wires that go to the inverter are there for the safety switches ect.. but I'm not sure how to bypass them. ................. I use this in the shop, and can run it on a switch... I just want it to run automatically when the door is shut... I'll turn it off on my own by putting a switch on the power cord... any help would be super appreciated.
I believe the 3 wires are control wires, to start the board without the microwave control circuit, the brown wire has to be grounded, the orange wire has to be grounded through a 1k ohm resister and the yellow wire needs a square wave of 220 Hz at 3.3 to 5 volts and a variable duty cycle to change the inverted output, the duty cycle needs to be atleast 43% or lower on start up then can be ramped up. Hoped I helped!
Excellent video. My Panasonic inverter Microwave blows fuse while sitting idle. Sometimes after one hour and sometimes after one or few days while door stays closed. I checked all parts are ok and the microwave works good while fuse is not blown. Please give your comments. Thanks,
Hi i have a similar microwave. It is the one without the knob. My microwave turns on and every thing looks fine. The fuse is good. But when i put in the time it rurns off after counting down 2 seconds.
I have a NN-T994 series. I did the water test, each in 03 one minute intervals. Each minute test, is faintly heard as, "bzzzt-pop!" (the sound lasting 02 seconds). A slight odor is also smelled, each time getting progressively stronger. I presume this is because the fan is cooling it. The last minute test produced a very light puff of faint greyish-white smoke. Any ides? Thanks, Gordon
hello... could you please show how you arrive to discharge the capacitor? in a panasonic inverter? for example I have a NN-SD277SR and they dont have the big capacitors everybody mention in the videos. It is amazing but most of the videos you find assume you already discharged this capacitor. can you help me on this? I just can see a 2 like a mica capacitor close to the macnetron. It has been hard for me even to access to where it is
Thanks for the video. I'm about to open up my 4 year old Panasonic Inverter MWO, model NN-SN797S. It started kicking off after 3 or 4 seconds (clock stays on) but will run continuously on power level 5 - most of the time. When it does shut off on level 5 it won't run again unless I let it rest 30 seconds. This will be a tougher one for me to diagnose as there is no total component failure. I'm hoping it's the thermal cutout switch, Part # F61456N60AP.
After removing the cover I immediately noticed the melted connections to the door switch. Found it at my local Fry's for $2.19. Cleaned up and retensioned the connections, oven works great!
I have one of the inverter power supplies (the newer type) on my desk to refurbish a iron core transformer model, but only have the -4KV and the AC connectors. Where does the magnetron heater supply come from!?
The HV connections (two spade connectors near each other) drive the magnetron heater, and supply the HV as well, relative to case ground. Make sure you connect the ground strap from the inverter to the oven case. You'll need to transfer the magnetron from the inverter oven as well, the heater in the inverter magnetron is higher voltage and lower current than the one driven by the iron core transformer. The inverter won't be able to power the heater in the old oven's magnetron, I've tried this before.
tesla500 Hello Sir, I have the same inverter problem, i don't know how it is call but it burn anyway also the board, so i bought a new inverter change it but it is that it powers up okay but shuts off 3 seconds after I start it. Please advice.
I have a Panasonic NNSD377S like your silver ones, it says 800W high power. It works fine but it has a loud buzz when in operation. Is that cause for concern? thanks
Thanks! It has been easier than expected to repair my microwave after watching your video. I saved a lot of money.
Great instructional video, a true professor of electrical / electronic mix technology. Thank you for sharing your knowledge and skills with the rest of us that enjoy understanding rather than just tossing, when something simple seems to be possibly fixable.
I'm from the mighty USA, as you are from the mighty Canada, both are awesome countries with knowledge abounding forward.
Brilliance comes with willing effort.
May peace and great success be with you always.
A brother in life, no doubt. ; )
Enjoyed the video. Thanks for taking the time to upload it.
Very helpful video.
I opened the case on mine and noticed 2 wires (orange and black) had melted off the connection. All fixed and works like a charm.
Most expensive coffee warmer upper haha
Thanks for the video. It helped me fix the problem with the door interlock switch.
Thank you for this great video. You obviously work very well and know what you are doing. I'll be sure to save this video and your channel in my lifelong references.
Thank you very much....This video helped me....i just finished repairing my Panasonic inverter...it was the fuse and the switches at the door...
Thanks so much for the video. My last microwave lasted me 10 years and was a hand me down from my mother. a Samsung probably 15 years old, still works but the wife wanted stainless steel. The expression "they don't make 'em like they used too" really applies.
Just repaired my microwave thanks to this video. Thanks!
A nice primer on the insides of my Panasonic Inverter MW. About 9 years old it was beginning to start-stop-start in mid-operation which I correctly surmised as an intermittent connection. I used a small flat head precision driver to remove those 4 Torx anti-tamper screws plus one Philips head on the right side of the case. Sure enough the primary micro switch showed heat damage due to the failing contact. I got a V-15G-3C25K on order. Thanks for your expertise and floating camera work.
UPDATE: Got the switch from Mouser. The connector lugs were damaged from the arching of the bad switch and had to be replaced. The new switch would not snap into place because of the mounting post wouldn't fit into the switch's hole. I drilled the hole one millimeter larger and it finally fit. The oven works like new. Parts: $3, Shipping: $8, My labor: $100, Aggravation charge: $200. Green Points: 10 (for not adding to the dead appliance dump).
Thanks for that comment about being able to use the small flat screwdriver! Saved me digging out my security bit set (wherever it went to!)
Great video, thanks for sharing it. Years ago I repaired our Kenmore microwave, it was an easy fix (the door micro switch was shot) Apparently if you open the door while the microwave is doing its thing it creates an arc across the contacts and after a few times doing that the switch no longer works. I was told by a neighbor and friend that if you want to avoid damage to the door micro switch you have to turn off the power (by pressing the stop/pause button first) before opening the door. My question for you is this... Two years ago I bought one of the newer microwaves that you showed at the beginning of the video and in the past week or so it has started to intermittently turn off while operating. If we closed the door hard it would sometimes work but when it turned off the turntable motor continuously turned.
Yesterday I decided to take it apart and try to see if there was a loose connection inside or maybe a bad ground. After taking the cover off I wiggled many of the wire connections and checked for any burnt wires but I didn't see any. After that I took out the micro switch on the door and it seems to work fine. After putting it all back together the thing doesn't even power up the display. The funny thing is the motor which turns the turntable inside is always on from the second you plug it in but no display, nothing. Any idea what might be causing this?
Love the kitty, always inquisitive....
@Metalcastr These definitely heat fast, but they do have continuously variable power down to 40%, unlike the pulsed mode that normal microwaves run.
No one seems to use the proper gauge wire anymore, especially in white goods. The profit margins are just too small to use any quality parts. The big players seem to be able to push UL or ETL into allowing them to do things smaller guys wouldn't be allowed to do, like drawing 17A from a 15A circuit or running 17A through such thin wire.
Haha, great video! I had the exact same microwave as the one that was already open at the start.
@Garcansdad Yes, that's a lot of current for a microswitch. It may very well be the microswitch dying, not the faston.
I've got some NSTs, a 15/60, 12/60 and a 12/30. Never heard of a 30kV one, 15kV is the highest I've seen. I've heard of (but never seen) a legendary 15kV 120mA NST, but they're very rare.
@ubuntupokemoninc Not quite, there's a 3rd switch that tells the control board to turn on the inverter, so all 3 switches would have to fail in just the right way for it to run with the door open.
went to see microwave, stayed for the cat. the hero! here is the switch.
It is common for those film caps to make noise. It isn't easily heard though unless they're up near ear level like that. It's very common in computer power supplies, but usually covered up by the fan noise.
I understand an additional ohm check on a Magnetron is to check the terminals individually to the outside casing of the Magnetron. They sometimes short at the terminals.
Hi, for the first machine you fix in this video, that switch you replace--the one connected to the door opening device--what is the part number for that and where can I order one?
Thanks!
As a qualified electronics engineer with forty years of repairing products and 30 years of microwave repairs trained by Sharp and others I am horrified that you have not mentioned how accidental contact with the high voltage areas around the magnetron can easily prove lethal. These appliances were repaired by a company I used to work for and a colleague (Television Engineer) used to debate with me how a high voltage shock would hurt but not do any more damage when I warned him about working on live units. He was used to accidentally receiving shocks from CRT screens of 25 000 volts but only a few Milli amps that would sting. Our training always told us to Disconnect before repair, open the door so no chance of powering up (should we have failed to disconnect) and Discharge any High voltage left that had not been bled away from the magnetron. My colleague was complacent and ignored this and was found dead in our company's workshop in 1995 when he had worked through his tea break and accidentally touched a working microwave, I know there is a lot of safety warnings that anybody with a little knowledge tends to ignore but when you are putting up a video that actually encourages others to work in such a high danger area without any warnings I find it very responsible..
I completely agree with you. I am also a qualified tech, but even before I was qualified I did factory training with Sharp 30 years ago. When we walked into class on the first day, "MICROWAVE OVENS KILL TECHNICIANS" was written across the blackboard. 2 guys walked out never to return. The instructor certainly had the full attention of those of us remaining. This video like many others like it, is reckless. I hope nobody having viewed this has hurt themselves or heaven forbid, died as a result. I've put in my suggestion to youtube that it be removed.
Nobody not familiar with electricity should be working on anything electrical! That is a given in most peoples eyes. I do believe that he is trying to help us that do know that these things are dangerous and do know how to implement safety precautions. So... Get your head out of your engineers ass and help us out here!!!
So how do I ask you the questions I have on my micro? You seem to have experience with these and the one I have is pretty much the same as whats shown on these vids but bigger. Would you reply to my questions on this comment page of his? I need to know whats going on with this...thank you for replying back to me though We that do know electricity need real help.
I know why the filter boards make that noise, it is normal (Panasonic said so)
He moved the cat.
Great instructional video! Thanks!
I have an NN-C994S and it has been working fine for 10 years. It recently started blowing the power strip I have it plugged into and I have had to reset it about 3 times in the last 6 months. Most recently, it started turning off 5 secs into a heating cycle. Now this just has to do with the microwave. The convection operation works fine which is why I am hesitant to just ditch it. I took the shell off and looked at switches in the door and nothing seemed burned. So, experimenting, I disconnected one of the connections to the magnetron and ran the unit. It shut off again but went about 10 seconds. I disconnected both leads to the magnetron and ran the unit and again, ran about 10 seconds and shut off. Then I plugged both leads back into the magnetron and ran the unit again and something close to the heat sink looking part on the Inverter board started arcing and the inverter burned pretty bad. No fuses blew and i turned everything off immediately. Is it safe to say the Inverter needs to be replaced? Is it worth the cost of the inverter? or could the magnetron still be the problem? I am at a loss as to how to proceed and like I said, hate to pitch it since the convection function still works and the combo is hard to find! Thanks for your guidance.
I found this video very informative. I worry about people with no electrical/electronics background working on these machines. I don't know why so many people have asked questions. The author of this video like most obviously doesn't have the time to answer everyone's queries about a myriad of fault conditions. This must be one of the most dangerous items to be found in a domestic environment for the unwary diy fixer.
I've seen burnt connectors (underrated for the current) way more than I can remember. The built up heat then has caused all kinds of different problems. I think most common has been on a regular oven the main over heating protector to fail because the bad contact burned the whole protector. After changing the (spade?) connectors I use pliers to tighten them even more. Manufactures tend to use those connectors that have lock mechanism so that the connectors don't disconnect from vibrations. But the problem is then that the connector itself is loose and cannot carry the current propely and thus heating up. I guess it faster to assemble appliances that have loose connectors with lock mechanism than to use a bit more force to push in a stiff (proper) connector.
Those loose connectors with locks are worst when used with magnetron. The ~3V heating current is quite high...
Hey I have the exact model in the video on the first two. The settings and everything work. I just can't seem to hit the start button after setting to the desired time. What should I do?
18 gauge wire can handle up to 28A depending upon the insulation. UL / ETL has lower limits depending upon the class of device and its function. Residential and commercial electrical codes for building purposes derate things even further. Alas, these are the only the specs on the wire.
In this case, the problem is likely to be hot spots with the crimped faston causing the microswitch to fail prematurely. Die wear, alignment, and pressure variation at the factory can all contribute to a crimp not meeting manufacturers current ratings. In addition, had that faston been replaced in the field at some point, its a real pig in a poke, as most hand tools do a pretty poor job at making crimps capable of handling that level of current. I learned this the hard way as a n00b engineer many years ago... A semitrailor full of rejected units due to harness failures leaves a lasting impression.
Thanks for the video, now I know exactly what to look for. I may end up replacing that wire in my Panasonic with something far more robust to prevent a future failure.
Is there any way that I can bypass the comms from the inverter to the control board at connector CN701?
I've tested my door switches (3 of them) for continuity, and they work OK. Is there another possibility for Fuse blown?
@filipkof I'll try drawing some arcs off one of these inverters. I have no idea what it'll do, but I know the inverter will survive a short circuit, so there's a chance it'll work.
On a 15A breaker, typically you can draw about 17-18A continuously on a good (new) one, and perhaps 30A for 5-10 seconds or so.
I want to see this video heh
I would really appreciate your advice. I have easily repaired dead microwaves over the years just by replacing the micro switches on the door latches, and one by replacing the magnetron, but after a month of tinkering with my Model NN-H965wfx Panasonic Inverter microwave, I am stumped. The fuse, thermostat, and all three door switches work perfectly. I tested the switches both in and out of the microwave to ensure the latch was actuating the switches correctly. I get power through the fuse, but there are no signs of life anywhere else. The display and interior light do not light up and the microwave is totally dead. As it began to fail this microwave would randomly power off like it was unplugged, and come on when you bumped the front side near the control panel. Over a period of a few days, it required more bumping till it just quit altogether. I thought it was just a door switch, but they all tested as good. What else could totally kill all power to the microwave? I am not a repairman or electrician, but I do have a micrometer and am determined to learn what is wrong. Any help would be appreciated.
The problem is popping the door latch before the microwave has timed out. You are therefore opening the door interlock microswitch under load causing sparking and overheating which extends out the switch to the connected wiring. You did exactly that in your test of the repaired unit. Use the stop or wait until timed out.
I just learned this 2 weeks ago when trying to find out why my 6 year old Panasonic would only run for a couple of seconds.
I've been doing it wrong for 30 years. Old habits are hard to break. LOL
I have a newer one of these [Panasonic [NN-T6648FX], got a Code 98. Fuse is fine. I checked the continuity on the Magnatron, have continuity between the leads, but also have continuity between the each lead and ground (this seems odd to me). Does this mean the Magnatron is bad? I looked at the manual but could not exactly figure out how to check the volts at the Inverter connectors CN702 (120v AC) and CN701 (3v AC) Also the manual says to press CLOCK TIME START POWER LEVEL to test. When I do this displays 88.90 (I think) but testing at the leads unplugged from the board I get no AC reading. So, what I really want to know is it the Magnatron, or the Inverter circuit that's bad. I want to get the diagnostics right first, then order the part. Thanks for any help you can provide! Thanks for your videos!
Hi there,
My microwave similar to these trips the circuit breaker in the house when I open the door. The door switches(3) all seem good. If I remove the earth wire nothing is tripped and all appears good.I tried using the garage outlet as it has a different breaker. When I do and I open the door the fan starts as well as the carousel motor and nothing trips. Any ideas?
Rickmoses: This was my problem too, but after watching this video and seeing that the current is too high for the door switch design, as soon as I opened my unit up and saw a burned connector to the very same switch Telsa500 showed us how to fix, I was convinced the burned connector was limiting current flow and that is why the unit was shutting down. That the switch was still working is why the unit operates for a little while before shutting down. I opted to repair the connector by soldering
Hi. I have an NN-ST761SF that runs for exactly 23sec whatever time you set. If you stop it after 10 or 20sec by opening the door, it runs for another 23sec! There is no heat at all. All 3 door switches appear fine - though one is N/C and 2 are N/O... I don't have a wiring diagram but presume that's normal. Any ideas?
5 years ago I bought Kenmore's best microwave. 13 months later, smoke started coming out of the the top vent and you could hear it was loaded up, pulling a lot of amps. Found a couple of loose spade connectors at the high voltage diode and the diode checked as being shorted. $15 replaced the high voltage diode and the cap it was connected to. Everything was back to normal. I don't know the differences between types, does this sound like an inverter microwave and what are the differences?
My photo electric smoke alarm had a false alarm the day before my inverter microwave quit. After watching your video, i guess it wasn't a false alarm after all. Same thing happened with my furnace a few years ago. It triggered an alarm and i thought it was a false alarm. Gotta learn to believe the alarm.
Thanks for the video! I have a Panasonic Inverter Microwave and hope you can help figure my problem. The microwave plugs in and lights up, when I push a minute and start, the LED light turns off, but screen is on. Interior light turns on, but microwave doesn't start. Buttons still make sounds and work. Any ideas and advice?
i have a few mosfets from those inverter boards - data sheets show the IGBT has a 60 amp rating! (with heat sink of coarse)
I have one similar to the first one you posted. I checked switches, megnetron, thermal switch, everything are good. But when I press START, no action, no sound, no fan, no light. Do you think it is the START button goes wrong or other issue ? Thank you .
Hi Tesla500,
I have microwave inverter nn-cf770m just two years, and it just suddenly stop working. Led is still on. when started it 1st run for 30' and stop. After few times like that, when started it turn off one of the the Isolator switch of the house. Do you have any suggestion on the cause.
Good post - thank you!
I'd be more concerned about the integrity of the spade connector rather than the wire itself. The contact area is minimal even when they are tight and in good condition.
If they are slightly loose, the end result will eventually be the failure that you illustrate.
Simple fix for me. The magnetron connectors were not snapped on securely. Thank you for the knowlege of this video.
NTP Vlogs are my channel. I share the reality. repairing Panasonic inverter.cho microwave oven You learn from each other's experience. A reference channel is very useful.
I am replacing my Panasonic NN-SA651S Inverter board. I forgot the mark the wire. I don't have problem this wires yellow, Brown and Orange, cos the it can only poke in one way, next I have this White and 2 brown wires, this I can plug in either way. I want to know is the White I believe is (Neutural) face outer side of the board and the remaining two Brown wires are face inside OR it can be on either side. Lastly the Two Red wires connect to the Magnetron from the Power can it be connect to either side?
Thank you and hope to hear from you soon.
I have a Panasonic Inverter Microwave that trips the breaker at the end of the cooking when the timer is done and the microwave switches off. Where do you think the problem is? If I pull the plug out before the timer is done then the breaker does not trip
Question is at the end of this You spoke of electronics safe cleaner . I have one, however customer left plastic container for 10 min, container liquidized and made a light orange film all over inside of oven, a very horrid smell like burnt popcorn x100, I managed to remove it (hours ) with a solvent. However the electronics area including inverter board still has it . I cleaned the fan , the sensor etc. Question you mention a electronic safe cleaning spray, what spray would you recommend? Needed a solvent inside the oven as a thin layer of plastic was causing the white inside to appear yellow.
My micro failed earlier this week. Was gonna open it and see if it was just a fuse, but decided against it. Just brought a new unit. I wanted to try an inverter type, but *people* just got to have a "pretty blue display" ugh.
Good job mate.. thanks GBU.
Hi my national microwave oven convection inverter type has an issue as soon as the start button is on the fuse gets blown out could u suggest an solution to this thanks
Hi do these inverter microwaves have thermal fuse in addition to the main powers upply ceramic fuse? Thanks
Very interesting and well presented. I have a NN-ST657S which the microwave is still working but the turntable and light suddenly went off. I checked the fuse which is still OK - nothing looks untoward - Only about 2 years old
yep I think it might be normal the buzzing
I have a red Mainstays (not an inverter) that also does the same thing
I think it might be coming from one of the small transformers on one of the controle boards.
Those tend to get noisy.
I've a Panasonic microwave Model number NN-A574SBBTQ about 6 years old and 2 years ago the bulb stopped working. Today I tested the continuity of the spade connections to make sure power was applied when the door was open... I figured the bulb was faulty. Anyway my multi meter accidentally touched together the spade connections of the bulb and this has now caused the microwave to blow. No power to it st all. It tripped out at the Mains, I checked the plug fuse which was ok, along with the 10amp and 16amp fuse inside the microwave. All ok but no display coming on microwave. Any idea what might be the issue?
I have an Panasonic Inverter combination oven. After setting a program, the oven starts working then immediately switches off ( issue with all programs, whether on Microwave or Oven mode).. Any idea what the problem might be?
Did you find the reason it was doing that ? (yeah i know after 4 years sorry...)
What can I do mine the door springs in and slowly pops back out, and when setting the timer nothing happens also it goes back to clock display.we give it a couple of bangs and we might get lucky and it starts.its the same model Panasonic inverter you are working on now.Help please thank you 🙏🏼
Hi i have an issue with my national convection inverter microwave as soon as the start button is started the fuse get blown out could u advice me with a suitable solution thanks
That noise that you hear from the filter circuit is cause my hi frequency noise on the AC line. If you where to plug a lamp with a dimmer in the same outlet that your microwave is plug into and dim the lamp, You will really hear is buzz from the triac noise cause by the dimmer.
so the new microwave inverters dont have stored charge ? i have 1 of them but waiting to see if it is safe to take apart for parts its been unplugged for about a week ?
I have a similar full size panasonic inverter microwave NN-L931BF built in December 2001. There is no light or anything on when plugged in. It was used regularly and was functioning properly during the last use. The power filter and inverter are on the same board for mine unit. Both buss ABC18A and temperature fuse are good. Do you have any suggestion for where to look afterwards? I am a novice but always interested in fixing everything in the house. Thanks. Gary
Nice tutorial. I can't believe they are running that much current through a microswitch. Along the lines of high voltage transformers - have you used any old school neon transformers? They used to sell units with 30Kv output at 60 Ma. They made great Jacob's ladders.
The last time I saw a 30Kv NST was when I was in high school (40 years ago). All I've seen since then is the 15Kv units.
hi i have amicorwave just like that one u using but the keybroad can deal anything
Hi, any help you can give me would be great thanks. I was wonder what can be wrong with my panasonic inverter microwave 1250. Every time you go and push the start button, it will reset. The microwave wont allow me to hit the start button. Everything goes blank like if I were to push the reset button. Thanks in advance
Hi, Have you ever modified the Panasonic Microwave so that there is no 10 Seconds delay before full power is emitted ?
I am trying to reduce the time to get it to start cooking right away (or close to it) at max power.
Nice video thanks sir
My fuse is blown too. How do I know which one to get for a replacement?
Where do you get the 17 amp figure?
13:44 It is called *piezoelectric effect.* And generally is more noticeable with ceramic capacitors. If ceramic caps are used in sensitive circuits such as audio amplification stages, they can also pickup vibrations on the PCB, just like a microphone.
interesting
It may be magnetostriction in the common mode choke.
@@whitcwa Didn't he remove the cm choke and the noise persisted?
There isn't 17 amps going through a 18 awg wire. The problem is popping the door latch before the microwave has timed out. You are therefore opening the door interlock microswitch under load causing sparking and overheating which extends out the switch to the connected wiring. You did exactly that in your test of the repaired unit. Use the stop or wait until timed out.
dont you check for continuity between magnatron filament and the magnatron casing?
Hi sir i have same like this every things working except to make heating So what can i do thanks
G’day Tesla500. I don’t know if you still monitor this post but if you do.....
My Panasonic NNCD987W Dimension4 microwave runs for exactly 1 minute at any setting then restarts with the “Welcome” message.
If I set the timer for less than a minute it finishes correctly with the “Enjoy your meal” message.
The machine is 7 years old but looks as good as new.
Do you have any advice as to the problem, can I replace or adjust something to fix it?
Your assistance will be greatly appreciated.
Cheers, Bazza.
I have a nn-sd978s panasonic microwave it worked great for years, then it started to smell burnt, and stopped working replaced the fuse and worked before we saw that the power supply connection had melted. Does anyone know where I can get a replacement psu board and the actual power cord. Can't find one for my microwave
my problem is the over the oven lights on the microwave dont work. Yes i have changed the bulbs . Any ideas ???
hey there I've been watching your video and I got the same problem. .... where can I get the the switch? ....really appreciated thanks
Impressive, have had the same model for over 7 yrs. no problems except for that control knob. Is that part of a sub control board or is a single control board? My control knob turns of course, but no longer will allow me to set any parameters any thoughts, and where can I pick these parts up??? Great video.
In your videos you dont seem to deal with discharging the capacitor before working on the components. Do you have any advice regarding this?
Interesting, I had no idea they even made inverter microwaves - maybe I should dig through some next time I go to the junkyard. They look pretty flimsy though, I imagine they're a lot more prone to failure versus a plain ol laminated iron and copper transformer.
Hi Tesla. I want to ask you for help... My MW Model NN - T695SFX has this problem... After I put over 30 Secs on the clock and press Start, around 30 - 40 Secs it stops and on the screen shows H98 .. Only that. And it's not heating anything at all... I'd like your thoughts... Even better if you show us how to fix it since there's more people with this same problem... Thanks in advance.
Carlos Gómez 😔I have same problem. my microwave shows H98 nothing else
My Panasonic microwave, model NN-T945SFX is behaving exactly as you describe. From this video, I'm thinking the inverter has a problem.
Did you ever get your problem fixed on your model NN-T945SFX? Mine is doing just what you mentioned showing the code H98 and not heating.
The error codes H97, H98, and H99 are used to indicate problems related to the inverter circuit and the magnetron. These codes appear on the display window
after the start key is pressed and there is no microwave oscillation. Check for magnetron filament continuity.
What causes the startup "squeal" or "screech" heard at 11:24 and 13:33? Is this a component of the inverter going bad, or a failing magnetron (inverter can't supply enough initial power)? This is a common symptom of many Panny inverter microwaves, but I haven't found the answer yet. Anyone?
"Let's get that thing running..."
"Beep... Beep... Beep... ZZZZZZZZZZZZZZZZAAAAAAAAAPP!..."
what is the name of the switch in the first microwave that u fixed sir?
Good video, troubleshooting... I recovered many uwaves when they were worth something - still have one old Amana - first of the consumer real stainless Inside too) when they were $900 in the 70s. Once my son called me "Dad the new microwave in the office brought down the power - they are throwing it out - do you want it?" I stiil have that one :)
I too hate to see the stuff go to "recycling" which is mostly just metal recovery. Have one Panasonic inverter in the kitchen, likely 2nd gen. I then bought an clean older one for the cabin for $12 and it flaked a bit , blowing fuses. I thought it was the crowbar switch but no. After your vid I took another look as I had assumed it was the inverter. Guess what? Magnetron was 220 Ohms filament to ground :{ Problem fixing them is room for that stack of carcasses! So I said nuts and scored a rarer white one (NNST651W) cyber Monday Bbuy $99. We will see how it does. Cheers
I have a panasonic sd277wr. It is about a year old. starting about a month ago some times when I press start it only turns on for about 1 second and then stops. I try again and it does the same thing. I have pressed about every button I can, I removed the power from the wall and it still happens. I disabled the turntable but no luck. Eventually it will start working just like normal. It may work for a week without problems but then it will do this again. What could be wrong?
hi have a micro wave that cut of after 2 sec can u help
I have a question: Do all microwaves use rotor blade fans (which we see in this video) as opposed to squirrel wheel blowers, the types found in stove exhaust vents? Blower wheel fans tend to be much more powerful; Have you come across any microwave ovens that use them?
Maybe you can help me, i have my mothers old NN-S577WC 1997 microwave, it heats but the light, the blower motor and the rotissorri motor does not spin,( although it works with 110 volts when disconnected hooked up to the wall socket ) i smell a burnt electrical smell but dont see anything but guessing from where the wires come from the main board to the blower and rottisorri motor i guess there is a problem in the main board, everything elseworks fine, even the srolling messages on the screen,
Thanks...nice video.
Mine is making a short circuit sound and smells really bad...kinda like burnt wires but worse.
That was exactly my thoughts when I saw it, seams a little unlikely that it would be something overlooked tho? for the few cents of thicker gauge wire
@ihatespam1977 It is unfortunate that good old iron and copper transformers are being pushed out of the market. They're very reliable, and good for experimenters. But if the inverters take over completely, I'm sure people will find ways to make use of them for HV experiments.
Gotta love modular components 12:05
How can you manually turn on the inverter? When I shut my door, the screen turns off and it automatically spins the table for a few seconds and then everything turns off... I'm assuming something is wrong with the boards...
I crossed the power wires on the board (blue and black) to bypass that relay.. and (while the display is off, because the door is shut) the table turns, and the fan runs... but it doesn't heat.... It still shuts off when I open the door (so that's good).
I'm assuming the three smaller wires that go to the inverter are there for the safety switches ect.. but I'm not sure how to bypass them. ................. I use this in the shop, and can run it on a switch... I just want it to run automatically when the door is shut... I'll turn it off on my own by putting a switch on the power cord... any help would be super appreciated.
I believe the 3 wires are control wires, to start the board without the microwave control circuit, the brown wire has to be grounded, the orange wire has to be grounded through a 1k ohm resister and the yellow wire needs a square wave of 220 Hz at 3.3 to 5 volts and a variable duty cycle to change the inverted output, the duty cycle needs to be atleast 43% or lower on start up then can be ramped up. Hoped I helped!
Excellent video. My Panasonic inverter Microwave blows fuse while sitting idle. Sometimes after one hour and sometimes after one or few days while door stays closed. I checked all parts are ok and the microwave works good while fuse is not blown. Please give your comments. Thanks,
Hi i have a similar microwave. It is the one without the knob. My microwave turns on and every thing looks fine. The fuse is good. But when i put in the time it rurns off after counting down 2 seconds.
I have a NN-T994 series. I did the water test, each in 03 one minute intervals. Each minute test, is faintly heard as, "bzzzt-pop!" (the sound lasting 02 seconds). A slight odor is also smelled, each time getting progressively stronger. I presume this is because the fan is cooling it. The last minute test produced a very light puff of faint greyish-white smoke. Any ides? Thanks, Gordon
hello... could you please show how you arrive to discharge the capacitor? in a panasonic inverter? for example I have a NN-SD277SR and they dont have the big capacitors everybody mention in the videos. It is amazing but most of the videos you find assume you already discharged this capacitor. can you help me on this? I just can see a 2 like a mica capacitor close to the macnetron. It has been hard for me even to access to where it is
+Angelica Escobar Just short the caps out with a screw driver
Thanks for the video. I'm about to open up my 4 year old Panasonic Inverter MWO, model NN-SN797S. It started kicking off after 3 or 4 seconds (clock stays on) but will run continuously on power level 5 - most of the time. When it does shut off on level 5 it won't run again unless I let it rest 30 seconds. This will be a tougher one for me to diagnose as there is no total component failure. I'm hoping it's the thermal cutout switch, Part # F61456N60AP.
After removing the cover I immediately noticed the melted connections to the door switch. Found it at my local Fry's for $2.19. Cleaned up and retensioned the
connections, oven works great!
I have one of the inverter power supplies (the newer type) on my desk to refurbish a iron core transformer model, but only have the -4KV and the AC connectors. Where does the magnetron heater supply come from!?
The HV connections (two spade connectors near each other) drive the magnetron heater, and supply the HV as well, relative to case ground. Make sure you connect the ground strap from the inverter to the oven case.
You'll need to transfer the magnetron from the inverter oven as well, the heater in the inverter magnetron is higher voltage and lower current than the one driven by the iron core transformer. The inverter won't be able to power the heater in the old oven's magnetron, I've tried this before.
tesla500 Hello Sir, I have the same inverter problem, i don't know how it is call but it burn anyway also the board, so i bought a new inverter change it but it is that it powers up okay but shuts off 3 seconds after I start it. Please advice.
tesla500 model is nn-c980b
i have this microwave that went i close the door the magnetron actives only. do you know why?
I have a Panasonic NNSD377S like your silver ones, it says 800W high power.
It works fine but it has a loud buzz when in operation.
Is that cause for concern?
thanks
+ᗒ╬ᗕ1112223333111ᗒ╬ᗕ
interesting, i have a gd566m panasonice, which has the fizzing/buzzing noise too
i wanted to know about it too
does anyone know?