Thanks for a great video that has diagnosis, repair as well as circuit schematic explaining the failure of the microwave followed by demonstration of the success of the repair. From your explanation in the video, I consider you very knowledgeable, and highly motivated in explaining to others. Hats off to you, Sir.
Nailed the opening sequence, Dave! That's an intro I can get behind! You still get your opening sequence, but we get an explanation during the intro. Brilliant move. As I said, I'm not fond of intros, but yours just became unskippable and informative. Nice!
thank you for your video. i finally understand the door switches now! please keep posting videos, you explain things clearly and concisely. thanks again!
Great video as always. Just completed on one LG having keypad problem. I didn't just replaced the keypad with a new one but changed the design entirely to eliminate the bloody dirty problematic keypad design to illuminate the trouble chance in future. Excellent video.
Thanks for a great video that has diagnosis, repair as well as circuit schematic explaining the failure of the microwave followed by demonstration of the success of the repair. From your explanation in the video as well as replies to viewers’ comments, I consider you very knowledgeable, and highly motivated in troubleshooting. Hats off to you, Sir.
Smashing you recovered it sir. Im with you with switchmode nastyness, i knew it wasnt a good replacement for the old reliable iron core transformer. Ive seen fuses pop for no real reason, never found a faulty switch. The machine is usually around 4 years old before the fuse fails.
My microwave panasonic inverter metal inside and out not cheap plastic is still going strong and it is just over 7 years old and is used daily.. the only thing that might be getting worn is the fan it sounds louder than when it was new. As the fan runs for a full minute after the microwave stops to help the inside cool down
@@paulsanderson8804 maybe see if the bottom of the microwave will come off to access the motor. One drop of light oil on the bearings should help. I have a cheap 800watt microwave, still ok 11 years later, but i bet the emissions from the magnetron have gone down a bit.
They sure do make them cheap and light these days. At work we have an original "Amana Radarange" in the kitchen at work. The company bought it new in 1975. Weighs a bloody ton and has more chrome on it then a 57 Chevy! It has been heating coffee and cooking frozen lunches for 42 years and still works perfectly.
They don't make em like they used to. I have 2 microwaves, the cheap Danby I use for heating my lunch, and my wife uses the old 1989 Panasonic Madam Grill. It bakes as well as nukes. She uses it more as a conventional oven than as a microwave, but when she does a roast in it, she uses both radiant heat and the microwaves. Food comes out brown like a regular oven but in half the time. Has never let us down. Got it as a wedding gift and it gets used every day. The old ones just keep on going. They were built like brick you know what.
Use the light bulb. When it tries to start you will see the brightness ramp up and down on the lamp. That means that the inverter is drawing power. If it goes to full brightness and stays there you have a dead short. As you saw I disconnected the magnetron to verify that it wasn't the cause of an overload. Then connected it, and observed the start up cycle again before connecting with full power on the current protected power bar. This one normally uses an 18 amp fuse, but I have stuck 15 amp in, and they seem to hold as long. The unit draws just under 15 amps when running.
I hope you will work on.some tube radios in the future,I love all your fixes ,the are all something to learn from.I always like your safety tips ,thank for this video.
Thanks! Your video allowed me to check the door switches which are functional. Any chance you’d have a schematic for the NN-SN778S Panasonic Inverter Microwave? My oven heats, but no power to the lamp or the carousel? Any ideas? Thanks!
They may be a pain to service but they are a joy to use. Mine has been fine but after I left it in storage a few years, the socket on the magnetron shorted so I got a used one and all is fine. Moisture killed it.
Nice video, THANKS! My model NN-SD986S has had both the switch connector problem and most recently needed a new inverter. The switch was the first to cause a problem a couple of years into service. I did NOT replace it because the switch is not the problem, the connector is. I cleaned the connector up then soldered the wire to the pin to allow better current flow and it has worked fine for years until the inverter. By disconnecting separately from the circuit both the magnatron and inverter, as you show in your video, I was able to isolate that the inverter was the component tripping the circuit breaker and confidently buy a new one. MCM electronics had the cheapest F606Y6G00CP at $80 (I spent $18 on clearance items to get free shipping, which paid for itself because my wife had just over paid by double the cost of shipping for three watch batteries that she was able to take back to the grocery store :-). Now, I wonder what went bad on the inverter? Fixing that would have been awesome.
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.
A good magnameter and radiation leak detector sure are good additions to service microwaves. But man are those things costly. When I got mine back in the day i paid out the ying yang lol. Always great videos Sir.
I had a leakage detector in the shop, and yes they cost a fortune. Never detected leakage on modern designed units. The old first generation with the doors that opened down was a different story. People would lean on them, or rest cookware on them when loading and unloading, and bend hinges and then there was a gap, and leakage. When they switches to the side opening door this problem went away. If the door is loose then that more of a concern, but modern units are pretty good.
My primary switch overheated and has very high contact resistance when closed. The fuse is okay but the unit doesn’t power up at all. Does the main circuit board get control power through the primary switch?
I have always been lucky because all of the microwave ovens that I have picked up from peoples' garbage,, except for some blown fuses, have worked. Then, i would spend at least an hour cleaning each microwave until it was clean enough to donate. Frank
We have a Panasonic inverter fridge and I personally thing it's awesome because it can run the compressor and the blower fan at variable speeds using variable voltages and high frequencies not the 60hz from mains, this makes it very quiet and very cold with energy savings up to 30% and it doesn't click and dim the lights for a second when it starts which means no causing of voltage spikes.
Yes they are very efficient. My electric car uses an 3 phase drive inverter for both the traction motor and the HVAC heat pump compressor. This is a slightly different application though. The early inverter supplies for the microwaves were relatively unreliable, as it is driving the magnetron tube,and people running them with less than the minimum load, such as cooking popcorn causes excessive VSWR in the oven cavity / waveguide which was very hard on the early designs. I am sure they are better now, but the early ones had very high failure rates.
Good evening, I had a problem with the same panasonic microwave oven. But my problem was the inverter circuit which gives sparks on it. I have dismounted the board and found out the power resistor was open. I have measured the power resistor and it doesn't gives me any reading in ohms. Do you know where I can buy this ceramic power resistor. Your videos are very good. Thanks!
Hi pls advice I have same model and it off and lock only after 3 second of running, it's inverter based. And as soon as it on it off and display shows lock. Fan runs properly
I have a Panasonic Inverter and it is showing SERVICE sign in the display. Lights turn on and the touch panel seems to work. When I press the start butting, it works for half a second and then with a click sound turns off and the display screen goes blank. Cant find any code like SERVICE through the internet search. Any thoughts? Thank yoU!
Hi I have inverter in the microwave, when I switch on the power there is no problem but when I press any button on the panel the mcb trips please suggest me to rectify the microwave
Good day, Sir. I have a Panasonic inverter "genie" microwave (Model PN-T17955FX) and it has been behaving erratically. Sometimes it works and other times when I shut the door, all signs of disappears. Other times when I open the door, the plate starts to rotate and the internal light is on. The switches seem to check out. However the black wire to the board seems to trigger the Welcome message. Any idea what to look at. Much obliged in anticipation of your response.
similar to our's, we got it at Sam's a couple years ago. So far, so good, does a nice job for a microwave. it's defrost is very good. thanks 12! btw, you did not mention discharging that nasty HV cap in there. Does it have a bleeder resister on it? They can pop pretty good when charged. I warn anyone who opens a microwave to beware of the megnatron cap. We had an Amana with the bottum hunge door, the 57 Chevy of ovens, liked the chrome door, lol. I used Litton commercial at my coffee shop, talk about a tank, indestructable. Don
umajunkcollector the inverter models do not have the big oil filled cap. they have a few ceramics on the inverter. modern conventional microwaves that use the old iron transformer, stack diode and cap usually have a bleeder resistor internal as well. just the really old ones like the old Amana don't and most of those also have a nasty surprise. pcb filled capacitors.
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,
I have Panasonic model nn-sd972s checked the fuse and switches are good, checked the thermal coupler is good....., there is no power or display. I have replaced all new switches and fuse and thermal coupler just to cover my apples and no power or display! Would you have any other suggestions that I may overlooked.
Do you think you should check the wall outlet with some lamp or test it with a line tester to see that there is power at that outlet. Alternatively plug the microwave to a different outlet where nothing else is connected since the microwave may draw approx 15 amp. I am no expert in this, just to eliminate. Your post was 2 Yrs ago. By now you might have already taken care of it.
Hi there. Thanks for the details of your repairing sequence. My question: I've got an NN-CS598. It stopped a few times and only an asterix could be seen on the display. After plug out and in, it could work. However it stopped now and plugging-in-out doesn't help. I can set languages but when I push buttons only an asterix comes. Fuses are all right, swiches are all right. If any of the fans becomes faulty may it end up in this trouble? Thanks for your support.
Hello, I have a Panasonic Microwave I need help with. Model NNCD989s, get a code on screen KG-C, dish inside turn but it docent heat, keeps turning when door is closed, can you help?
Show how to discharge the capacitor 1st. Also can a 2013 inverter unit be replaced with the new cyclonic unit? Or does the magnetron also need to "match: I've cyclonic donor unit which has smashed door etc , parts are good
What was the current rating of the fuse? What current limiter were you using that you set to 100 watts and what is the max setting? Okay, found one answer further down in the comments. Fuse was 18A SB.
Hi sir i watch a lot of you vedio it 's very inspiring and i learn a lot from them , i am working on a panasonic inverter microwave similar to the one in this vedio suddenly the display went off and microprocessor is getting hot and it emits a little smoke .Sir is there any way to do a bypass on controller board or any thing i can do turn on the inverter circuit.
Thanks for your videos. I have Panasonic genius sensor 1300W inverter microwave that chips the breaker after 2-3 secs. After disconnecting the magnetron it runs fully for the time set. I checked the magnetron and it appeared fine. No cracks seen in the magnets either. Any suggestion?
We had a Sharp Carousel 2 microwave with a mechanical timer. It lasted almost 28 years with no repair. Had to stop using it when plastic inside the door broke. It fell when I opened the door.
Is it normal for a 1250 watt micr to draw 16.7 amps when the conversion on 1250 watts to amps of 120 volts is 10.4 amps? the instructions say it'll draw 12.7 approx but when I did an amp draw after replacing the fuse it draws 16.7. That doesnt sound right to me... I need answers please...
People confuse microwave output power with input wattage which is way higher especially with the inefficient transformer types which the poster seems to prefer.
Is the Inverter a ROYER Power oscillator you know the one that has a feedback coil across the bases of the power transistors and biased via a 56K resistor.
I didn't look at the design. Back when I was still in service these units were just hitting the market, and we were not permitted to repair them. All we could do was determine if the fault was the inverter or the magnetron. When the inverter was bad it was sent back to Panasonic. They were all sealed up, and potted at the time, so all we had access to were the input plugs and HV terminals. Someone at Panasonic deemed they were too dangerous to repair. I didn't remove the shield on this to see if the parts were accessible.
Hello, I have a Panasonic Inverter 1200W (NN-T695SF) bought like 10 years ago and it started to do some free games couple of month ago. Sometimes, it takes weeks before it fails again, it's a very intermittent problem. The problem is the unit shutoff like 20-30 sec after it started. When it want to fails, it makes like a couple of buzz sounds and the light flickers a little bit inside it (at the same time of the buzz) until it shutoff. After that, if I restart it, it will shutoff again and again couple of seconds after it started. For now, the only quick way to fix the issue I have found is to unplug it and replug it to the wall. After this trick it will works perfectly (no buzz, no flickers) again for a couple of days in a row until it will restart to fail again. Always the same way, buzz sounds, flickering light and shutoff. What do you guys think? Can it be the fuse or a switch? Thanks!
I've just brought a panny inverter microwave and felt like watching some diagnostic videos for reference. Anyway, although this video is old, I noticed when the microwave in this video was cycled.. The turntable only partly worked and stopped. Not sure you had noticed that. I replayed the video to check and handle of the mug didn't come around. Could a non rotation cause fuse to overload or pop?
Turntable wasn't sitting in the spindle correct. It popped off and just dust there even if the motor totally seized up it couldn't draw enough current to blow an 18 amp fuse. It is a small motor like an old clock uses with gear reduction.
@@12voltvids oh I see, that makes sense. I was wondering if you noticed a slight somewhat judder as the plate turns.. The one I have does not revolve smoothly, with slight momentary pauses, but then at other times (programs) it seems to be smoother. Do you think this is inherent in the engineering and function? Thx
Nope. Transformers are just that. A big iron core transformer that steps 60Hz 120V to 60hz 2100 volts. Rectified by a HV diode, and filtered by an oil filled capacitor then to the magnetron. An inverter changed the 120V AC to about 160VDC, then a high frequency switching mode power creates a high frequency PWM waveform that goes to a smaller HV "Flyback" type transformer, which generates the 2100 to 2400 volts for the magnetron. Filtering is done with small ceramic caps. The advantage with inverter type microwaves is true variable power, as they just vary the duty cycle of the PWM going into the inverter drive. Conventional microwaves are either on or off. Power levels are set by cycling the full power on and off. Inverter types have true variable power. So if you set the unit to 50%, you get 600 watts. On a conventional you get 15 seconds of 1000 watts, 15 seconds of 0, Then 15 seconds of 1000 watts again and so on. Inverters cook better, but are more complex, and the early models were very problematic. Conventional is cheaper, and far more reliable. My own microwave is conventional, and it works fine for what I use it for, reheating stuff.
When a magnetron fails it will either loose power taking longer to cook or it will just stop heating completely. If it is making a humming it could be the transformer, capacitor or stack diode, or the cooling fan.
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.
Likely the inverter is blown, or solder connections burnt up. One word of caution about the magnetron. If you get the leads reversed you will blow the magnetron and the inverter. The leads on t he magnetron are polarized. One side goes just to the filament, and the other one goes to the filament and anode. (One side has an F and the other FA). The Anode side has over 4Kv on it, and the filament only side about 1.5 volts difference from the anode. Get them reversed and it will arc internal and burn the tube out and take out the power supply. Stack diode in conventional unit, or inverter board on an inverter model.
@@12voltvids .... The Inverter was the only thing that was arcing.......the capacitors look pretty burnt. I pulled it out but am debating whether it is worth the $100+ bucks to replace it. The trouble I have is I cannot find a combo Convection oven/microwave to replace it. I can find just a Microwave but then I lose the convection feature. Everything else looks in perfect condition. Any thoughts?
@@kredfish00 Yes I would replace the board. I also have a convection microwave and would definitely spend money on it because as you said they are hard to replace. If it was a straight micro then forget it.
OK I replaced the Inverter. I tested the microwave with a cup of water and it tripped the overload switch on the powerstrip it was plugged into after about 10 to 15 seconds. I checked the water and it was warm. Where do I turn next? Do I replace the magnetron?
@@12voltvids OK I replaced the Inverter. I tested the microwave with a cup of water and it tripped the overload switch on the powerstrip it was plugged into after about 10 to 15 seconds. I checked the water and it was warm. Where do I turn next? Do I replace the magnetron?
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
Disconnect the 2 red leads from magnetron and keep them away from anything metal. Try starting it. If it runs through the time cycle and doesn't shut down, then you know the magnetron is bad. If it still shuts down, then the inverter board is bad.
On mine a NN-CD545B I came home to a burning smell. The input filter pcb was black and had been smoldering away for some time. The T15A fuse was ok so it did not protect against this fault. The pcb is beyond repair so if I can't find a replacement I will make something on a bit of vero board
CAN ANYONE HELP? I have a Panasonic 1200w inverter microwave. The turn table did not turn, I went to you Tube and thought was the motor, so I changed a brand new motor. It runs a few time and it stop. now it back to the square one. Please advise, what else can go wrong with this Microwave? Looking forward to hear from you. Thank you.
Hello i have a Panasonic Microwave Model no. NN-C784MF so the problem that i have are some of program pad could not working so what is the cause behind that ?
Something strange. On my panasonic microwave. The light cover on the inside next to the magnetron is melted. I do boil a lot of water. But also, my microwave shuts off after 32 seconds.
Hello sir I have a Panasonic inverter and I don’t have any issues with the door switches but I am getting an h97 on the display and the magneto is making a sound like marbles rubbing together
Unplug the magnetron wires and try starting it (stay well clear of the wires as they will energize to about 4000 volts. If the noise goes away then it is likely your magnetron has lost it's vacuum and is arcing internally. Time for a new magnetrom or oven.
Nice video, i have just one question there's no high power capacitor on inverter models, how do you discharge this equipment before is safe to handle? I have one panasonic with a bad door switch i think, it doesn't recognise the door closed and nothing happens when start button it's pressed display its fine.
There are a few capacitors on the inverter board, but if the inverter is working, they discharge as soon as power is cut (as the inverter is running, and will discharge them quickly) There are also HV capacitors but they are very low capacity, and are on the inverter board as well, so as long as you are not removing the inverter board you are safe. The switches are on the AC side, and as long as the unit is unplugged there is no risk. Where there is risk if if you have shorted inverter transistors, as this will pop the fusable resistors on the inverter, and thus the primary capacitors will hang on to a charge for a few minutes after the power is removed, but as most power supplies these days, there are bleeder resistors to discharge them in the event that the inverter is not working.
This is the second Panasonic Microwave video with a bad fuse I have watched, I wonder how many Panasonic Microwaves have been scrapped for the sake of a dollar fuse? Very bad design on one hand or very good design if you want to keep selling microwave ovens.
They can be serviced, but I would not recommend because they are extremely dangerous to work on. 4000 volts 1200 watts, you do the math. Enough current to kill you in an instant. I have repaired them but would never show servicing one doe to the extreme danger on that board.
knunne1 the turntable is turning fine. the fuse popped due to the owner heating those gel heating packs that you put on sprains and sore joints. those things are supposed to be heated in a pot hot water as they are very hard on microwave ovens. of course I wasn't told this initially. regardless when the fuse blows the switches need to be removed and checked as they only protect once.
I have a Panasonic inverter mico and it worked fine till I decided to put a square bowl that was to bigto turn in in. Then after that I tried to reheat something and the breaker started tripping then the micro stopped working all together. I did some research and found that the fuse was blown so I repaced it with a new one but, The microwave I have is supposed to draw 12.7 amps and its drawing now 16.7 which will trip the breaker when anything else on the same circuit is running. I cant find anyone or anything on line that talkes about too high of an amperage draw so I'm stuck. The micro is only 2 years old and was a good one. So we bought a new one which is fine but I still want to know what the part is that is making the thing draw too high of amps. If anyone has any idea I would greatly appreciate your advise. Thanks for reading my rant...:-)
I have a Panasonic microwave that has suddenly decided to work for three seconds before shutting down. From what I've read here it sounds like I might be better off just putting it in the dumpster and buying a new. BTW, it's an overhead microwave (as in over the oven). Any suggestions?
Might be the magnetron. You can disconnect the HV leads from it and see if it still shuts down. If it doesn't then the magnetron is bad. If it still does then the problem is likely the inverter, and you are correct when inverter goes bad you might want to just replace the oven as the are pretty cheap these days, and those inverter modules are not easy to service, and have some extremely high voltages and currents that are lethal.
@@12voltvids have tested my switches will have to try this thanks. I measures the resistance of the magnetron some where I read a short circuit is a sign of failure but they are expensive too any way. perhaps not worth mucking around with can be dangerous I hear!
@@cerulyse You can't test the resistance of a magnetron. It is a vacuum tube. The 2 terminals sticking out are the filament / cathode. They will measure a dead short because the filament is only running about 2 volts at about 40 amps The antenna is the anode, and it will measure open between the cathode and anode. The only way you can test a magnetron is to put power to it and see if it enits any microwaves (heats the food or water)
@@12voltvids ok thanks, someone else on here said you can check for any sort of connection between case and the terms is bad ie Meg ohms scale but sounds pretty unscientific 😕
It most certainly DOES work. Too bright in the shop. Lots of lights. Camera doesn't pick it up but it definitely works. It is back with it's owner, and if it didn't work, I would hear about it.
Sad you don't like repairing these. We LOVE the true fractional power output. better than any other microwave technology... if only thy would make it more repair-friendly!
Back in the day authorized repair centers were not permitted to repair the inverter boards. They generate 4200 volts at what about 300ma. That's a whack of power, enough to generate 1200 watts. Will kill you before you know what hit you if you are not careful. For liability reasons the warranty centers were only permitted to swap them out. I heard something about service kits to fix them but that was after i left the business.
Hi from the UK, find your videos very informative, thank you. However, I have a problem and dont know if you could or would give me some advice. I have a Panasonic dimension 4 Inverter 1000 watt microwave and it seems Ive had it forever, always been brilliant and I love it. The white fuse recently blew, so we replaced it My son put the casing over it but didnt screw it in, then plugged it in, & it all lit up as it normally would. But before I could test it with the cup of water, my son decided to move the st/steel casing, against my advice, it then touched the spade connection that powers the bulb, which is on the top on this model, (pink & white wires) it shorted and now we have no power at all. we have tested the 3 switches which are all fine. The white fuse is ok and the glass fuse is also ok. Cant see any scorch or burn marks anywhere. Power is coming into the unit, through the glass fuse, but no power to the white fuse. Call us stupid, I would agree. Do you have any ideas as to what the problem might be please. I would like to have a last try before I send it to the microwave grave yard. Thank you in advance and Ill keep my fingers crossed you can/will help. Kindest regards, Jules x
A conventional microwave has a simple HV transformer and a capacitor / diode operating as a voltage doubler. This pumps the 2100 volts from the transformer to about 4200 volts DC that feeds the magnetron tube. It is either on or off. No in-between. To lower the power for defrosting for example, the system is turned on a few seconds at full power and then off for several seconds as the intense heat in the edges of the food conducts towards the center to defrost it. The problem is the surface gets hot and the food starts cooking while the core is still frozen. On the inverter microwaves the mains AC is turned to DC, and then back to a high frequency square wave drive signal that drives a pair of MOSFETs that switch on and off to drive a flyback type transformer to produce the high voltage for the magnetron. By varying the duty cycle and or frequency of the switching waveform driving the transformer will bring the transformer closer or further from its resonate frequency therefore changing its effiency just like any smps. This allows variable output voltages from as low as a few hundred volts all the way to 4200 volts. By doing this the magnetron power can be accurately controlled from as little as 100 watts to 1200 watts. So for slow cooking or defrosting the power can be turned way down and kept constantly running allowing the good to defrost without cooking the edges. I use it all the time. Take a steak that is frozen solid. Punch in the weight and hit go. It is defrosted perfectly in a couple of minutes ready to hit the grill.
Do you have a video on replacing the inverter board? I have one similar to one of the other people on this chat Panasonic I have replaced the wire harness and a switch that was burnt I also checked the magnetron and the fuse that only leaves the inverter board to replace thank you so much for showing us this tutorial if you have an answer please notify
Phillip Jones I don't have a video showing inverter replacement but I just found another Panasonic inverter microwave. The last one I found ended up being in perfect working condition and I am using that one now at home as my main microwave. Someone tossed a brand new one in the trash if you can believe that. I think the overheated water and it erupted inside the oven and they got scared and thought something was wrong with it and turfed it. Anyway I have another one I will be working on relatively soon and it might need an inverter repair. Haven't plugged it in yet.
Well shit happens. Sometimes this is all that is wrong. I was hoping for a switch failure. Had it been the inverter it would have been scrapped. The reason is those inverter boards are extremely dangerous to service. Even for very experienced servicers. They generate 4kv at close to an amp. Panasonic never offered service parts for these units just an entire board replacement. What you learned is fuse holder causes fuse to overheat.
That will pass 10+ amps no problem. I ran it up on a light bulb first to verify no dead short. How big do you think the conductor is in a 15 amp fuse? The jumper as you saw did not over heat. This was for a test to verify that there was no other fault. Now the proper size fuse goes in, and the unit goes back into service.
This is how testing is done. A current limiter (light bulb) is put on line to verify that the unit has not suffered a catastrophic failure on the inverter, and the magnetron is not shorted. Had I had the correct fuse I could have put that in, but I didn't so I plugged the unit into a 15 amp circuit breaker, which was also on a 15 amp breaker to the plug. So it is not like I took the protection out, I just moved it back to the other side of the AC plug. Go poke your head into repair shops, and see how it is done. Nobody wants to blow a fuse UN-necessarily. When I was taking my apprentiship and a TV came in with a blown fuse and nothing obvious a resettable circuit breaker of the fuse rating was jumpered in while the unit was tested, and if all OK then the fuse was replaced. The KEY here is I HAD A SECONDARY breaker between the plug and the microwave in the form of a fused power bar. So I am still testing under overload protection.
Go listen at 10:27. "It is plugged into my 15 amp power bar, so if it draws too much power it is going to trip the breaker in the power bar" So, there you have it. I replaced the fuse, for testing with a 15 amp breaker. The fuse incidentally is an 18Amp ABC microwave (which is a sloblow fuse) so I actually have better protection than just replacing the fuse. I do know what I am doing, and I wouldn't be showing dangerous things. It makes NO difference if it is protected at the fuse holder or at the other end of the plug, as long as there is protection between the mains outlet and the unit. As you saw I did trip the breaker in the shop, as I had my plasma, and monitor, and the lights on the same circuit, and that oven draws a lot of power. My bench power is actually on a 20 amp circuit though, so the power bar with it's 15 amp breaker protects anything under test. Now, if it was a 5 amp fuse I wouldn't do this, but the fact that the original fuse was a higher rating than circuit breaker in the power bar, I am safe. No go back and wipe that egg off your face. Obviously you haven't been in the game, long enough. Every shop I worked for used circuit breakers during testing. It just doesn't make financial sense to stick a new fuse in just to have it blow if there is a fault. Sure you might say it is only a buck. Add that up, and those dollars add up quick when you are running a business. So we used re settable circuit breakers. I had a set ranging from .5 amps to 10 amps. We used them in ALL repairs while units were under test, and then replaced the fuses just before sending them out. This is how competent technicians work and we always look for a way to save a buck, because a buck saved on materials used in a repair is an extra buck in profits. Now today I picked up a pack of new fuses, and the unit is awaiting pickup, good as new.
@seventeesweremagic - I'd draw a line when saying someone is stupid... definitely not called for. FWIW, I've been doing this over 40 years and every time I run across some good silicone-wire, I save it to make up decent leads. I can spot a cheapie at 10-yards and it moved by itself at the end of each run. Since this channel is quickly building an audience and maybe headed for star-stats, he sets an example - that's all... Try to be a little more civil.
Omgs bypassing a fuse with a jumper wire you're insane! lol the comments... I've done a lot worse than that, people would have a heart attack if I made a video fixing some mains powered device Jumping out a fuse is standard practice anyway when you know what you're doing, and it saves fuses
As I already pointed out to Einstein, go back and listen to 10:25. Quote: "It is plugged into my 15 amp power bar so if it draws too much power it is going to trip the breaker in the power bar" There I saved you the time. I am not stupid, and I work very safe, and would never suggest removing fuses. All I did was move the protection from the fuse holder, to the end of the power cord. All done to save fuses as they are expensive, especially these microwave fuses. Nothing insane or dangerous or hazardous. Over current protection is still present, actually more, because I ran with a 15 amp breaker, and the fuse is an 18 AMP slo blow.
Lol I think you just repeated what I said. I was laughing at the comments who got all upset about you jumping a fuse, not saying what you did was stupid. I'd have to call myself stupid at that point because I do same thing all the time when I'm troubleshooting. And I already know that everything you were doing was current limited, I have almost the same setup with a dim bulb tester and a fused variac and iso transformer. I don't think my sense of humor gets across sometimes, sorry about that. Youre still one of my fav channels out there lol
12voltvids In our business repairing commercial micro's, I made 2 gizmos to clip onto the fuzeholder,made from 10 and 15 amp circuit breakers. Used only for testing.
I have a Panasonic 1200w inverter microwave. The turn table did not turn, I went to you Tube and thought was the motor, so I changed a brand new motor. It runs a few time and it stop. now it back to the square one. Please advise, what else can go wrong with this Microwave? Looking forward to hear from you. Thank you sir.
It's called isolating the fault. Fuse was blown but we don't know why. In this case it was just fuse fatigue, but usually they will fail due to either one of the switches failing, the magnetron failing, or the power inverter. So we tested using a limited current source in this case an incandescent light bulb and we test it with the magnetron disconnected. If a switch was the cause of the problem the light bulb would have glowed bright even before starting the unit. Had it been the inverter the light bulb would have glowed bright as soon as the unit was started. Had it been the magnetron as soon as the magnetron was connected it would have drawn excessive current. As we reconnect one stage at a time there's no fault showing so then the unit can be safely powered up from direct connection to main voltage and tested and it worked thereby proving that the fault was actually a weak fuse. More than likely the connection between the fuse holder and the fuse was not good which caused heat in the end of the fuse which ultimately stressed the fuse like and caused it to fail.
