Microwave Doesn't Work? These Are The Reasons Why!
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- เผยแพร่เมื่อ 25 พ.ย. 2024
- Microwave stopped working? Here are the most common reasons why!
To learn electronics in a very different and effective way, and gain access to Mr Carlson's personal designs and inventions, visit the Mr Carlson's Lab Patreon page here: / mrcarlsonslab
#restoration #electronics #repairing
To learn electronics in a very different and effective way, and gain access to Mr Carlson's personal designs and inventions, visit the Mr Carlson's Lab Patreon page here: www.patreon.com/MrCarlsonsLab
Very good teaching video I hate the throw away time period we live in Old people bought stuff that would last and fixed it when broken Thats how they saved up all that money there kids squandered Lol you know I speak truth lol Them switches can be a pain to get working right even with good switches
@@ambersmith6517 I have a fridge that I purchased some 50years ago, and still going strong. So far, I've replaced about 5 electro-mechanical defrost timers - now using an electronic replacement - but otherwise it just works. Of course simple tech is not all rainbows and unicorns, and the downside is that it's not as energy efficient as "modern" variable speed compressor versions, but I suspect that the total energy cost with regularly replacing less robust but more energy efficient appliances, may be a wash.
Paul if I wanted to microwave my perfectly calibrated 50ohm glass of water for 2 mins should I enter 1:20 or 2:00 on the keypad? Thanks for all the great content throughout the years. ❤
😅😅😅
Left a post here about that capacitor I like that safety is job one with you. One of my co workers forgot to discharge the capacitor I saw it happen it really scared me. Lucky he wasn't injured. Really appreciate your many videos and excellent presentations.
Your brief but concise warning on the hazards of a microwave oven as with anything electronic is very much appreciated. Excellent video.
a was going to point the same, thank you Mr Carlson for the warnings, many people get hurt playing with these devices, they think high voltage and radiation are toys
Safety first always. A little knowledge is dangerous so to have all of the facts is what you need. If you still want to be stupid then it’s up to you. Love Mt Carlson’s lab. Just found it.
"A 50 Ohm glass of water" - That’s the joke you get when a electronics and radio engineer repairs and tests a microwave oven! 😂
It was actually deeper than most plebes will get.
I don’t remember the exact formula, but if you place a cup of water in a microwave oven and measure the temperature rise of that water after being heated for a certain amount of time you can determine the power output of that oven.
Dummy load.
@@stevenedington6265You could, but it wouldn’t be precise. A lot of the microwaves gets wasted by just bouncing around without hitting the water.
To the optimist, the glass is half-open.
Mr. Carlson, all your warnings and cautions are absolutely warranted. Thank you for this instructional video.
We have a Sanyo microwave oven that we bought brand new in 1976. It has been in daily operation ever since. So, you're right, they don't build them like that anymore. 😢
agreed, the 70s was the last time they built anything, 'like they used to.'
I have no idea how old my microwave is but it used to belong to my late wife and she already had it when I met her in 1991. That thing just keeps chugging along.
My mom's house has an avocado green fridge from the 70's. That thing will live to see the sun burn out and then watch the heat death of the universe
Yeah. But it probably cost the same as 10 microwaves do nowadays
When you need 4 people to move the dang thing you know it was built to last!
I worked on appliances for years. The most common problem by far was what you found, a failure of one of the micro switches on the door which then blows the fuse. If one of the door switches momentarily sticks while opening the door, which was usually the case, they are wired in such a way as to immediately blow the fuse. Often the door switches were very intermittent when they failed so i learned if there was a blow fuse to replace all the door switches, or most likely you'd get a call back. So glad you made a point about discharging the capacitor AND not plugging in the microwave with the cover off, as there is No reason to, you can do all the troubleshooting you need with the power off. A young tech, just 22 years old, working in our town back in the 80's was killed when he touched the wrong wire or connection on a plugged in microwave that had the cover off. I had talked to the lady afterwards who was in the office at that time and she had hear him yell "Oh No" and came back to find him laying on the floor.
Why would the fuse blow; some intrinsic safety design or was it due to a gross SWR imbalance?
@@BlackWolf42- Generally there are three door switches: One signals to the timer that the door is closed (so the timer stops when you open the door, also shutting off the magnetron). One is in series with the magnetron and so also turns it off when the door is opened. The third is across the magnetron and closes when you open the door, deliberately blowing the fuse if the other two switches have not shut it down yet.
Certain combinations of bad switches will then deliberately blow the fuse as a last-ditch fail-safe.
This can also happen if the door latch is worn or the door is twisted or sagging, which changes the relative timing of the operation of these three switches. Such failures tend to be intermittent (for instance they depend on where you grab the handle to pull the door open) and tricky to diagnose, and replacing the switches doesn't help.
This particular oven seems to have a fourth switch which detects when you are pressing the door release button.
Wish when mine failed it was that easy. Not sure what went wrong but every time I'd use it it would pop the breaker.
@BlackWolf42- Most Microwave ovens have 1 Switch in series with the main fuse directly across the incoming Mains if the other switches fail on with door open it blows the main fuse straight away 100% failsafe 😂😂
Good to know. Thanks! I've noticed that nearly all hardware stores sell fuses for microwave ovens. Every oven I've worked on (not that many) use the same size fuse. So evidently a blown fuse is a very common problem. I've repaired several ovens just by replacing the fuse. They work fine for long periods of time, so I always wonder what caused the fuse blow. Is the fuse itself sometimes defective? Good to know the problem might be related to sticking door switches.
To an electronics engineer a half filled glass of water is 3db down.
Oh, I thought it was the glass was twice as big as it needed to be.
@@scottpelletier1370 Sure, the glass is 0dB!
Nice.
Pessimist engineer: The glass is 3db down.
Optomist engineer: The glass is 3db up!
@richardgoebel226
I think you mean a glass 0.707 full is 3db down....🤣
Thank you Mr. Carlson. One of your best videos. Here is an object lesson in what can go wrong. My mother's microwave oven had a door seal failure of some type, she closed the door and set it to cook some food. She stayed near it and it burnt her arm. I have no idea how the door seal failed, but the door was closed. My sister threw it away before I could investigate the cause. All those door switches and sensors are needed and should never be bypassed.
Your caution is entirely justified. Your distain for present appliance construction is so true. I loved your 50 ohm glass of water.
all microwaves leak, some real bad and some not so bad. ours, you have to stay back at least 15 feet. some its only around 6 feet.
@@curtbilyeu8701 Health Canada regualations say "Part III (Microwave Ovens) of the Radiation Emitting Devices Regulations (C.R.C., C. 1370) specifies the following limits for the leakage radiation at 5 cm from the surface of the microwave oven:
1.0 mW/cm2 with test load
5.0 mW/cm2 without test load
To cause burns requires 1 watt or more of radiation/cm2 . That is 200 times the allowable radiation. That was a nearly new oven with defective safety devices.
The plastic hooks that hold the door shut broke on our microwave after barely 3 years of use. Now... I'm not wanting to replace a $200 appliance for lack of a $0.20 part. I didn't trust the janky replacement the vendor wanted me to buy, which looked worse than the original. Fully aware of the face-melting magic of the Magnetron, I decided to make my own. It took a couple dozen iterations of CAD+3D printer, with fitment experimentation on the unplugged appliance. I'd managed to make a replacement part that opened and closed with the rest of the mechanism flawlessly, tripped all the safety switches appropriately, and it held the door shut better than the factory part. Added bonus, I could now close and latch the microwave door with just one finger, in one motion, which I couldn't even do when it was new.
5+ years later, that microwave is still in service, with that same part, nobody's been irradiated, and no fires started. Aside from the bulb burning out since then, it's been perfectly reliable. If one understands the machine, and understands the problem, one can fix it. I learned that with this channel. Thanks Mr. C!
Microwaves aren't that bad. Ive played with bare magnetrons and if you come closer they feel like getting close to a fire, you can feel the heat before you get burned. The cornea fogging, balls cooking tales of microwaves are just exaggerations or product of extreme exposures, is far more dangerous to stare into a charcoal fire, glassblower's glory hole or a forge than a microwave oven with the door open.
This is an illustration of my preferred approach (not that I have anything like those skills):
“I don’t repair. I reengineer.”
Thank you for this! I have this exact microwave. It still works, but sooner or later.... We have no problem latching the door, but it often refuses to release when you press the big button. I designed and 3d-printed a door handle, and stuck it to the door with 3M command straps. What were they thinking when they used aluminum connectors?
@@xptechmikie Did the whole thing with Autodesk's TinkerCAD. Totally free to use. There are probably better tools to do that kind of thing, but brute force combo of patience and design iteration worked for me. 😅 NGL -- ended up with a stack of scrap parts that ranged from "didn't work at all" to "almost working, but..."
A microwave in 1982 costs 500$US, made by Gibson.
I think that is 500$US * 5 = 2,500$ in today’s money.
That is probably why it lasts so long.
Today’s 200$ microwave is suppose to break in 1 y.
A washer and dryer by SpeedQueen costs 1000$US in 1982. That’s 5000$US.
How much do they cost now?
Family member's 90s microwave failed a couple months ago. It was the door safety switch, replaced it with one I had lying around and it is as good as new. The thing has a massive blower assembly with a shroud around the magnetron to cool it. Almost like they wanted it to last. Strange, right?
One more thing: when I opened the front, there was a piece of paper stuffed inside with a wiring schematic on it.
I told them if they ever want to get rid of the thing, I'll take it.
some of them have the schematic plastered on the inside of the cover.
Designed for serviceability... Good.
I took apart an older faux wood ge spacemaker. It probably had a 20 page service manual inside it. It was tossed because the deflector thingy was getting stuck on grime.
@@joshluvhalo yep, you have to look for those, my dishwasher had a small folded paper taped to the frame, it unfolded like a roadmap with all the schematics and tech tips like what button sequence to invoke the diagnostic modes. Saves service calls!
I have had a few with the schem right inside. Super convenient!
Smiling!
Built in wall unit microwave over the oven. Microwave quit working so wife called sears because she saw a recall on door switch. I had replaced it a couple years ago, but she wanted them to come out anyway. Sometimes you just have to let them do what they want, even if I knew it was a waste of time. Sears tec Told her 800 dollars to repair but didn't charge for service call.
Turns out the magnetron was bad, ordered new on from the part number along with cap and diode. 75 dollars and working good now for years.
50 years of ham radio has saved me a lot of money, knowing what little I do about electronics.
Good one sir.
73
That is the cleanest interior of the cooking chamber of a used microwave I have seen. Qudos to those responsible for keeping it spotless.
Clean is right, it was probably cleaned before making the video. I repair Industrial dual magnetron Microwaves for restaurants. Managers need to train the employees proper maintenance procedures. Cooking grease and half cooked burritos are really gross. Some of these oven cavities really turn my stomach when I work on them.
I had this problem twice on my 40 year old Quasar microwave. After the second repair, I changed my way of using it. Instead of opening the door to stir the food while cooking, I now use the ""Hold"" (or "Pause") button to stop the oven before opening the door. So no more sparks on the contacts of the micro switches.
Blame the kids. Did my part as an 8 year old. Old plates with gold trim made a nice lightshow.
The "fine china" that the 'rents saved for guests.🤣🤣
When I came to Japan, my wife freaked me out by putting metal mixing bowls in the microwave - the stainless steel bowls seem to work fine with no issues - but the gold trim on her souvenir cups really arced!
Taking danger to the next step 40++ years ago, why just risk RF radiation and electrical hazards, let's add toxicity into the mix.
Test the microwave by putting the mercury thermometer in and turning it on.
Very spectacular as the mercury vaporised, shattered the tube and formed a plasma cloud.
The ignorance and stupidity of youth.
lol
I did worse, far worse. The glass door of my microwave litterally exploded. How did I manage to blow up my oven ? I tried to cook an egg ! I thought I was smarter than that: I knew an egg wasn't a great thing to cook in a microwave, but I figured that if I put it in a glass of water, the water would get all the energy, boil, and cook the egg... well, obviously that's not what happened. The egg turned into a bomb and when the shell failed, the pressure inside was so huge that it shattered the door into pieces. I would never have thought that an egg shell was so strong... I suspect what happened is the layers of albumin near the inside of the shell cooked first, making it stronger and stronger, until the inside boiled. Fortunately, noone was in the kitchen at that moment, else that would have been a very very bad trip to the hospital with lifelong sequels. I'm surprised there were no warning in the user manual that trying to cook an egg wasn't just a bad idea, but a very dangerous one.
Dad was the first certified microwave oven technician in Arizona; he had to attend a class and use a leak detector on every unit they sold or repaired. Most problems were with the multiple micro switches on the doors. When ours failed at home in 2014 it was the high voltage transformer secondary winding so it was a little spectacular, and smelly. 😊
There is nothing like the smell of burnt transformer.
That usually happens when the transformer core cracks, and it essentially saturates the coil much easier - things tend to get real hot real quick, and wire insulation starts melting
@@gorak9000 Ones I've seen all had EI cores. I can understand it if it was a ferrite core but I've never seen one. Maybe the more recent ones are?
@@stevenedington6265 Try a burnt florescent ballast!
You can usually tell when the transformer is on its way out as they often start to make a pronounced humming/buzzing sound and as you say there is usually the stink of burning lacquer on the copper windings.
Mr. Carlson: Oh the microwave died, don't worry, I can fix it.
Mrs. Carlson: This is why we can't have new things!
That what my wife said 30 years ago. No kidding.😅
Mr. Carlson's microwave oven is as clean as brand new like the clothes dryer repair video. 😆. Ever cook bacon in it?
@@petermetro4686 They sell lids for a couple of bucks you know, you can put them over plates and it keeps all the spatter and gunk to the inside of the lid. Then you put the lid in the dishwasher, and presto, your microwave stays cleaner.
@@gorak9000 yes we now have a dedicated covered bacon fryer for the uwave. Still a lot of steam from cooking foods clings to the inside of the cavity . Boiling some vinegar and wiping out the cavity keeps it fairly clean. Add some cloves to eliminate cooking odors.
My missus was delighted when I told her I was bringing a new dishwasher home,
....until I brought the dishwasher in and showed her where the sink was..😆
Sears Home Services here. We do indeed wear Kevlar gloves and yes when a door switch goes out it is policy to replace all three.
Nice to see someone else who keeps their over clean. I have a very old set of appliances and they all look new. Even the stovetop.
Every microwave I had in my shop to service was filthy. I did a 10 minute test on one once. I placed a large bowl of water in the oven and let it run for 10 minutes. When I came back there were roaches crawling out of it.
When you said you had a fridge from the 1950 and it never failed, I recall the first fridge we had when I was a child. It was way older than I was born in 1963 and it went into the basement when we got a new one in the mid 1970’s then handed down to my cousin after that. It’s probably still running somewhere. Built to last is a forgotten saying. Good for you Mr. C. Love your channel. BTW I fixed my microwave 10 years ago still going strong.
We used to nickname one of the door switches the 'crowbar switch' - it's purpose was, if the door hooks engage the switches out of sequence, such as someone trying to bypass the door safety or if the door hooks were worn out - to link live to neutral and blow the internal fuse (And usually the switch itself) Any time the unit was completely dead the first thing we would test was the door hook to see if either had too much play, followed by the internal fuse (As the hooks could be checked without opening the case) and the interlock switches.
Noisy operation - diode and capacitor test, followed by examining the magnetron antenna and waveguide for damage. One brand used to LOVE burning holes into the waveguide.
Clouds of white smoke in operation - Transformer failure.
Note - we used to come in after the unit had failed so we didn't generally get to intercept the problem early, these were also commercial microwaves tending to output 1800 / 1900W. Fun times.
Ah, too bad. I junked an 80's microwave from childhood because it was blowing fuses pretty much immediately and I figured something big shorted out. Had no idea that the switches were designed to short out on purpose. I thought my magnetron or something shorted. Was planning on replacing it with another 80's model, as they're far better built, but the only thrift shop locally that would put old microwave ovens out burned down not long ago - perhaps because they put old microwaves out, among other things. My mother won a microwave in 1981 and it's still running in 2024 so far, thankfully.
I thought there might have been something like that because I noticed that at least one of the switches closed when the door opened instead of opening.
In electronics there is actually such a thing as a "crowbar circuit" that is designed to blow the fuse in case of a voltage surge. So calling it a "crowbar switch" is pretty accurate.
@@soundspark Crowbar circuits don't always blow a fuse, but they do stop something from raising by shorting to the opposite rail. Crowbar voltage regulation with a zener for example.
@mikafoxx2717 I was tought a crowbar circuit in electronics was a circuit where when tripped would trigger a SCR to short the power rail to ground blowing the PSU fuse.
In 1985 I bought a top of the line Tappan touchpad microwave and aside from a couple 15 amp glass screw in fuses and 3 light bulbs it's been flawless to this day...
My Dad showed me a magnatron he extracted from a broken microwave when I was a kid (early 90's) and he explained what it did, which I kind of understood, but he didn't scare the bejeebus out of me like this did :D
😂
Absolutely!! Mr. C. is RIGHT!! A microwave is not to be fooled with. The tiny holes in the front cover are engineered; designed; selected so as to prevent rf energy of the microwave's frequency from escaping. If your microwave misbehaves toss it out. Get a new one or get a professional to repair the broken one. Microwave energy RAPIDLY excites the tissue of protein causing water to boil off and rapid heating results. KNOW YOUR LIMITS.
the pink part on the magnetron is quite toxic if it breaks or crumbles..
Be afraid very ack!
@@bashchelik100 They don't use beryllium on consumer microwaves. The pink insulator is the same material that tig welding cups are made out of - it's essentially just alumina / aluminum oxide / man made ruby
I just wanted to say that you are one in a million. You definitely are a genius at fixing stuff. Love your videos!!!
Thank You for your kind comment Mitchel.
I've tested the diodes by putting them in series with a bulb. It it glows at half brightness and somewhat flickery, you know it works. If it is shorted, you'd get nearly full brightness, and if it is open, you'd get nothing or near nothing. If you want to get fancy, use 2 of those diodes, one stationary and one to test. It should either be half-bright or nothing, depending how you turn the test diode. Half or nothing both ways would be a problem.
Thanx so much Paul! Sometimes we all forget that your 'knowledge' cost YOU something, either in time spent learning, or in the acquisition of test equipment.
Nice to show how a microwave works with all those safety devices and the electronics behind it. Got a 1996 Sears
Kenmore microwave that may just poop out tomorrow but still works like new.🤞Mr. Carlson's has an excellent
microwave that since now repaired should last twice as long since he bought it. Great video Paul!
Mr Carlton you’re a very intelligent man. Blessings to you.
I was impressed on how clean the inside was, mine looks like modern art with all the constant splats
This was a very practical video, Paul. Thanks for taking the time. I'm a broadcast transmitter guy who's been in a bunch of microwave ovens and this looked like virtually all of my troubleshooting sessions and was resolved pretty much like all of them too -- those pesky switches just don't like switching line voltage across a transformer thousands of times and eventually fail. I just think of these things as a little tube transmitter with interlocks that fail and it's just like the day job!
18:52 The switches and holder are sold as separate items. The switches can be removed without breaking the retainers. On that particular switch, the tab at the very bottom of the holder is the key. Pressing that tab will allow the switch to rotate on the pin counterclockwise. When the front of the switch is pointing downward, there should be enough clearance, to pull the switch straight up out of the holder. Also, it's common for people to just open the door to stop a cook cycle. This is very hard on the switches and can cause them to fail prematurely. It's best to use the stop or cancel button instead.
...Excellent info re rotating the switch to release it. Thanks
"Also, it's common for people to just open the door to stop a cook cycle" We call this "normal operation". If they didn't want you doing this, they'd lock the door shut while it is running.
@@stargazer7644 The interlock switches are there for safety, not normal operation. Opening the door during operation causes arching across the microswitch contacts, leading to failure.
@@GenerationXT That is utterly ridiculous. All switches are DESIGNED to break current. Again, if they weren't, then they wouldn't let you open the door during operation.
I never knew/thought that high current would flow through the micro switches, but thought that they'd trigger something else (like a relay, either mechanical or solid state) to stop the magnetron.
And I've opened microwaves during the cycle a gazillion times without problem. Guess I was lucky 😂
I also repaired a few of the newer ones, had one that needed bulbs for the screen, then I accidentally broke the tv screen, that tv belonged to my brothers wife. Transceiver repairs temp me but at age 77 that soldering iron is getting shaky, and taking the transceiver apart is pain to say the least. Thanks for sharing your videos!
I wonder how many microwaves get tossed in a dumpster for a problem that is this simple. Safety tips, as always, are much appreciated.
The answer is loads of them do. It is rare that the magnetron or the large step up transformer are the culprits.
It is more often a minor component such as a relay,a micro switch or a thermal fuse that stops play.
My slow-blow fuse goes every few years, just due to heat break-down. I'd be on my 4th microwave if I didn't know better.
I have a collection of microwaves that I have repaired with just these type of problems. The last one Had a few roaches stretched across the control panel shorting out the panel. They were electrocuted and were stuck in place.
Great channel, watch it often. As a RF engineer, I love anything related to radio testing. Just a thought, you can use a simple DC power supply to check the diode...... well sort of. I set the power supply to its max output of about 40v dc and current limit the supply to say 200mA. A good diode will show a forward current flow, and no (zero) reverse current flow. I acknowledge that the diode may have a damaged reverse breakdown issue at higher voltages but at least its a good start, and have measured several diodes using this method and they worked in the microwave oven. Obviously if you have a power supply that goes up to > 9000v DC then you can check if its reverse voltage is within specs. Most microwave diodes are rated to about 12kV reverse voltage. .
The trick to getting the switch out is to move the first tab like you did then pivot the switch around the post you pointed out instead of trying to bend the second tab.
Fifteen years ago... microwave stopped cold. Open it and shorted across cap to discharge. Tested everything... all good. Two weeks, later... quit working. Opened, again, and R&Red all of the spade connectors, suspecting galvanic corrosion, like you found. Back together. Two weeks, later... quit working. Getting frustrated. Open it up, again, and R&Red all spades, again... but, this time I recrimped the spades, while they were off the posts. Fixed! Fifteen years, later, still works better than new. Yeah! Thanks for your info... good job covering the bases!
I had a sears kenmore microwave that was made in the mid to late 90's that lasted for over 25 years and then I bought a new one right before the lockdowns in 2020 and it only lasted 3 years and the sears was blowing the breaker and the other one would not stop running unless you opened the door and now I have a new one. Also listen to what Paul says guys cause my brother in law tried to fix a microwave back in the 90's and he touched the wrong part and it threw him across the garage.
A Kenmore microwave will last about 25 years from back then. Can't say that about any microwave made today
by a longshot.
@@hestheMaster I agree
@@hestheMaster Amana makes commercial grade microwave ovens that are designed to last a very long time under heavy use. I bought an Amana RCS10DSE for home. No frills, no gimmicks, just twist the dial to the time you want and it goes instantly.
Man, I hope your in-law didn't get hurt too much.
Sears Kenmore, KitchenAid, Roper, Estate etc, are all made by Whirlpool. Prices depend on the bells and whistles they put in them, but anything made by Whirlpool is very good.
Mine is a Whirlpool and it has lasted over 20 years, it was top of the line under cabin with lights n fan but I found it in the trash, so fixed n used it.
Magnetron: probably the only vacuum tube that's still around in modern households (not counting nerds and people who had devices from 2000s and earlier).
The VFDs and CRTs common in the '90s/2000s? Gone...
I still need to get that bottle of Tarn-X, it's just hard to come by here in Poland.
Hi Keri !!!!,.lol, how r u? LIVE this sunday?
i might have told ya,. im 48% Polish per 23@me,. i wish i could visit the mother land,.lol
@@0ctopities feeling a bit sick now, not sure if I'll be there.
"go look for some tamper proof bits" - I usually use the universal tamper proof bit - the angle grinder! J/King of course, but almost any screw becomes a slot screw with a dremel and a little cutoff disk (including carb needle valves that need "special tools" to adjust them - not after a slot is cut into the top of it :) )
An easy hack with these type screws is to give them a nice tap with a screwdriver and hammer. Then you can usually wedge a small screwdriver in it and take them out that way. That way they’re still intact and you can put them all back when you’re buttoning everything up.
I'm not a Neanderthaler , I just use the correct bits, they cost not much 🙂
@@pa4tim But you're failing to consider the most expensive commodity - time - you have an unknown yet finite amount of it - don't waste any. Waiting for cheap bits wastes time.
@@gorak9000 I do not understand. I have several set with special bits ready to grab at my workbench. Why does that take more time? When I say they do not cost much, I do not mean they are max cheap. Good tools cost money. What I call "cost not much" could be expensive in your vision.
I have, among others, a set from Wiha (99 euros) and one from iFixit. (59 euro) And about 10 sets not holding all sizes.
Ifixit are small sizes, Wiha too, but also has some bigger sizes, the others have for most only medium to bigger sizes.
Grinding a slit and then grab a screwdriver for that costs way more time, besides that, I do not think my customers like it. 😁
@@pa4tim The term BUTCHER applies.
Here in Europe, those thermal cutouts in microwaves are either self-resetting, or manually resettable with a button. I bet those spade terminals are not aluminium, but some kind of brass or bronze with nickel plating. The terminals on the cutouts are silver plated, hence the tarnishing.
They do not fail with 230V, because of the lower current draw. Only 115V where you need 20A rating, instead of the common 15A rating for 230V use. Switching 20A is what kills those switches and trips.
@@SeanBZA That's true for the door switch, but the thermal cutouts should not switch the mains current under normal operation, only in case of malfunction, like a failed cooling fan. On the other hand, increased failure rates for the door switches in 120V areas should not be true either, becuase no one should stop the microwave by opening the door. It should be stopped, than the door opened.
I'm also guilty of sometimes stopping it by opening the door, but only becuse some microwaves have no 'pause' function, and the only way to continue cooking without having to re-enter the time is to open the door.
A lot of the silver coloured ones are actually steel plated with a zinc coating like 'Zintec' The brass spades are normally just left as they are without plating.
@@howardosborne8647 Yes, I know, but he tested it with a magnet, so they are not steel. Or they might be, but in that case they are stainless steel.
@@mrnmrn1 Nope, those spade lugs are definitely Brass. They don't use stainless steel on electrical connections in microwaves. Remember, these things are made cheap and Quick.
I Have a Microwave from the 70s with a wood grain surround and vacuum fluorescent display made by Toshiba Model No ER-893ETA Still works like the day it was new
It's amazing how fast you diagnosed the problem with this unit. Additionally, I see that the only tool you used was a multi-meter. I reckon the multi-meter is by far, one of the most valuable tools you can have at your disposal for doing electric and electronics work.
One trivia point worth noting about microwave ovens. Regardless of the brand and model, there are only about three actual companies who actually make these units and they are all nearly identical. A microwave costing $799 or $1299 will be no better than one costing $299.
I've had the same microwave oven for more than 30 years now, it's my first and only.
I had to fix the time handle once, and IIRC I changed the light bulb once - no other maintenance at all besides cleaning. It's a 900W super cheapo no-name I paid around $100 for. I could buy any other brand/model now, but it works 100% and most of all I can't find a modern one with the same functions and dimensions.
my discount store nuker from 2006 has the same oven cavity as mr. carlson's.
The same was true of VCR's from back in the day.
i know of sharp and panasonic, who's the 3rd?
@@voltare2amstereo The third seems to be a company named Midea in China.
Great channel!
One comment on aluminum connections. They are usually coated with a zinc cotaining contact fluid at the factory. The zinc particles pierce the aluminum oxide coating to attempt to maintain a good electrical connection. What you see may be the reaction product of the contact fluid with the aluminum rather than oxidation. Without the contact fluid aluminum mechanical connections are very likely to become resistive over time.
Keep up your educational series.
Jimmy Johnson
This guy really can repair almost everything, his vehicle, his power generator, his fridge, and now microwave.
😂 Has anything you can not repair so far ?
I have no idea at all about your electrical work, but I am very happy watching your videos.
Really made me fall to sleep easily at night ! ! 😅😅
I believe the Cybertruck is designed to be impossible to repair.
Took mine down from over the stove & took it all apart & could not find anything wrong. I was surprised that Amana included a troubleshooting chart for the Magnatron. So I put is all together & plugged it in & VIOLA!!! It'd been working ever since. The "Laying of the hands".
🙌 too often true!!
18:58......OOPS!!!!! Press tab down at lower left of switch and they swing right out and off. No need to break plastic tabs. Ask me how I know-LOL!! Excellent vid-keep em coming!!!! :)
In the past I repaired lots of TV’s that had 30 to 40 thousand vdc on the tube. I was very careful about draining off that voltage. I think I will stay away from microwave repairs. I do wonder what that microwave tube looks like. Great video Paul and great knowledge you shared about being safe. I enjoyed!👍
"These things are put together in 5 seconds- and- you only get one chance".
TRUE!
Hello I just wanted you to know how much I appreciate you sharing your knowledge I have learned so much from you and others on TH-cam and I can't thank you enough
You are so welcome
your microwave is so clean, lol most of them of them look like a crime scene inside
Fascinating. I have a turn-dial microwave that was gifted me, back in the late 1990s. I use it nearly every day. In 2024 it works fine. Though the plastic is turning a bit yellow.
Keep it. It will never fail.
I had a fetish for a while....I was collecting dead microwaves for parts. Especially the transformers. My 20A ham shack 13.8V DC supply uses 2 in series. They both had rewound secondaries to take the down from kV to V....by putting them in series you lower the magnetising current from 1.7A to 300mA. So I homebrewed a DC supply in an old PC case. The magnetrons may contain Beryllium Oxide as an insulator which has dust that will cause deadly lung disease. So NEVER bust the magnetron open!
Great video Paul. It annoys me to no end that at our local transfer station, there’s a palette that I call “mount microwave”. So many dead microwaves that are failed for simple reasons like yours. If only the manufacturers would spend a couple of bucks more, they’d last way longer. My current microwave failed because the PCB mounted relay that triggers the magnetron was at the ragged limit of current capacity. Replaced it with two relays, one pilot, and one with contacts beefy enough to last a long time.
Very smart of you to not have that water in a closed container like a PET bottle - i found that out 30 years ago. The explosion destroyed the lamp and caused much hilarity in the repair center where i did my apprenticeship. This video would have come in so handy back then.
I've heard one can have a lot of fun loading a PET bottle with some dry ice and some warm water too
@@gorak9000 Drain cleaner and aluminum foil tends to do the trick as well.
@@JulianA-tr6pt dry ice and water has the advantage that it doesn't spray concentrated sodium hydroxide all over the place though
Who in their right mind heats anything in a closed container?
@@stargazer7644 dumb 20 year olds, starved of excitement
Great video as always Mr Carlson. We had a microwave at work that when you opened the door it would still work. Rather than change the 50 cent switch they threw it out since it was very old. I should have grabbed that sucker for the parts or fixed it myself.
Back in the 80s. I know a guy who put a dozen of eggs in his Microwave without poking a hole in the shell's. It took him a week to clean the kitchen. 🥚 (blew the door right open)
0:30 I have two fridges from the 1950's, one in my house, one in my 32ft RV, they both work flawless. 🥰
Your microwave is immaculate inside! Mine looks like a nuclear disaster, a waveguide shield failure waiting to happen...🤣
Had a microwave for 30yrs finally wore out but the new one lasted only 18months, it blew the high voltage fuse so i replaced it and now I only run at 75% and it seems fine but time will tell. When it stopped working I came to the realisation that there must be thousands of MW Ovens thrown away that were quite fixable. Good vid Paul.
I think they use " tamper proof " to keep you from finding they have fuses inside !!1
I have scrapped at least 50++ , most of them failed because of " BLONE FUSE " ?
Thanks again ;)
Very cool. I like to endeavor into fixing any of my home appliances or electronics in my house, I have whirlpool microwave that have not used for about 12 years now because most likely it has a bad switch it in but then again I am not a big fan of using microwaves to warm up food. One day when i get some spare time will open it and take a look at it. Most likely it has the same switch issue as this one. Thanks for the tip.
Cleanest inside of a microwave I have ever seen
I used the TarnX idea to get my garage opener light working. I enjoy your channel.
I like the 50 ohm glass of water part. Let’s measure it with the multimeter to make sure it is 50 ohms!! Hahaha
I hear you should always change the electrolytic resistors on old appliances.
@@drworm5007 very funny. I like that response. You think like I do.
Hmmmmm.......... how do you measure the surge impedance of a glass of water? I guess some sort of sonar process. I remember seeing the derivation of the impedance of air (377 ohms) in the ARRL microwave manual.
Old electrolytic caps should be replaced, as they may leak out over your circuit board.
Powerful and clear speech. You are the bestest.
Unironically, my microwave died last week, and I, too, had to dig in and diagnose the issue. Turns out that the door interlock that passes the mains current to the transformer must have arced out a bit and would lose contact after about 45 seconds. Let's see what yours turns out to be.
I also spent more time searching for my darned tamper driver kit than I did actually fixing my unit. 😂
Great video Mr. C and honestly a very helpful and practical one. I bet this happens more than we think. Just the explanation of the internal operation was worth the watch for sure. I doubt if many folks will repair their own microwaves but this was valuable knowledge none the less. Thanks for the education as always. 73
Glad you enjoyed it!
0:46 thats some spite right there!
**REBELLION INTENSIFIES**
Excellent Paul ! Now a days I fix M-waves for folks all the time. I test the HV Diode WITH a 9 volt battery in series with it. It has just enough umph.
I have never seen a cleaner microwave.
It was cleaned prior to the video. Nobody wants to see the aftermath of an overcooked bowl of chili.
i love high voltage,. great video and diagnosis, THX Mr. C
If Ive learened anything from you ive learned one thing. If its from the 50s and it still works, itll work for probably another 100 years.
Fun fact also, all microwaves are built in a single factory in China.
Nice to watch this. Thank you! 😊
I especially liked seeing that variable voltage Octopus tester in use with a vintage O'scope. Those vintage instruments when repaired and enhanced are really nice to use. ❤😊
sometimes it's not the door switches but the door latch followers cut a groves into the plastic ramps they ride on and not actuate the switches correctly. So i cut some hard plastic and used some epoxy to glue the new ramp surface in place. The switches usually also blow a protection fuse when they don't work correctly.
HOw do you have a microwave long enough for it to fail and yet it still looks brand new inside?
@2:27 - I am still rocking an old Maytag washer and dryer from the early 80's. Sharp edges - yes. Reliability - rock solid. We also own a particular brand of Kenmore/Sears microwave with a pizza oven in the bottom. A dual unit if you will. My wife and I got ours for our wedding in 2011. We still use it daily. My father purchased the exact model about 15 years before we even got married. He gave it to me and my next door neighbor still rocks it today. Needless to say - they took that most reliable machine off the market.
Man posted in one minute and four unseeable spam responses. Unbelievable
Once you get popular enough the bots latch on to your channel...
Amazing that TH-cam can't even catch them re using the exact same profile pictures on every new account. They aren't even trying...
Google is in cahoots with the Spam bots. They don't ever try to stop them.
Greetings. Thanks for sharing. It is always absolutely a pleasure watching your videos. I watched the video not to learn since I am already quite experienced in microwave oven troubleshooting and repairs but to immerse myself in the mastery of your electronics knowledge.
My microwave is starting to fail, but it's nothing to do with the magnetron circuit. The vacuum fluorescent display is getting dimmer and dimmer.
Of course it's been operating nearly 24x7 for 16 years.
Microwave ovens are rated for 5 years in Europe
I have a built-in microwave oven (Kitchenaid) made in 2005. A few years ago, the display and controls stopped working. Taking the oven apart, I discovered a resistor in the low voltage power supply had burned up. Using my resistance substitution box I determined that it was a 100 ohm resistor. I replaced the resistor with a 100 ohm, 1/2 watt resistor and the oven worked. It was surprising to me that the original resistor was only a 1/4 watt resistor, and it was dissipating over 1/4 watt. Looks to me like they planned for it to fail......
@@keitha.9788 possibly indeed, but microwaves are unfortunately very dangerous if broken
Great video! Be safe, do the easy things first. This is my philosophy on most things, but I didn't know much about the inside of a microwave oven. Now I feel like I know a little.
Never stop a microwave by opening the door, always just press the cancel button. When you open the door while the microwave is on, there is a chance that a large current goes through the fuse, which then blows.
Thank you! You just fixed my old microwave!
Fixed my Bosch from 1995 in 2018, the HV cap shorted after leaking oil, we've replaced that (and fan a couple times in its long life) and it is still going strong.
That was quite interesting. All those sharp edges and brittle plastics are par for the course I think. I tried heating a glass of water in 20 seconds in my 1100w microwave and it was just luke warm, maybe I used 100 ohm water by mistake. 😊👍
Love keeping my appliances going, and my Emerson Microwave, it still looks nice with all the stainless. Got tired of the bulb failing every so many years so I installed an LED.
Nice to watch. Microwaves always scared me. This made it more understandable how they work in action. I like all the safety switches they put in to make it safe. I'm buying one soon. Thanks!
Have you ever used this microwave oven? It is absolutely spotless both inside and outside.
When my parent's microwave stopped working, it was the electrolytic capacitor in the controller board (for the voltage regulator). It's a "made in USA" unit from the 90s. I replaced the capacitor about 10 years ago, and it still works.
Pushing the door closed at the center and not at the top or bottom can save you from a fuse being blown, as the door can flex and not activate the door switches properly in turn shorting a switch and maybe blowing the main line fuse. I’ve seen this many times, usually with the over the range microwaves, good video regardless, thanks.
Big help thanks so much.
I think I have something similar going on with my microwave.👍
No problem 👍
Nice video I will keep that in mind when I have future troubles with my Microwave. Thanks Mike
Interesting. Still using my old Auntys Sharp MW with the big rotary dial.. its thirty yrs old.. solid as a rock.
Mrister Carlsons lab you are good at restoring antique radios and alignment of antique radios my friend
Interesting repair video. I had not realized there were Aluminum faston connectors, something to keep in mind if I ever run across them. Aluminum is a strange material for that type of contact but as you said built to the lowest cost.
I can see no sensible reason to think they are aluminum.
They weren't aluminum, they were made of Brass. They don't use Aluminum connectors in microwaves.
I have the same screwdriver set as you . I bought mine at Aldi
I had the same issue few months ago. Main magnetron power interlock micoswitch was defect. Got a new one for around $5 and hope it will last anoter 20 years!
Great as usual, I have changed out many Door Switches, Thank God They use multiple.
So true about "(too) fast assembly", my grandma's modern microwave wouldn't start, and it appeared to have entire case misaligned, so that door wouldn't fully close. It did close enough to work initially, but over time the plastic scrapped off the door and piled under the metal, eventually blocking the door enough for the switch to stop closing.
I've had one fuse failure, one controller board rot out due to bad design Samsung knew about and kept shipping anyway, and two power transformers gone open (on very old microwaves) and I've never seen anything like those aluminium clips. That's some real yikes right there.
(And thanks for the validation of never plugging it in with the case off. I've not done and wouldn't, but still.)
Okay, that was pretty good, Paul. Now let's see you tackle a new GE top loading washing machine. Complex to the max and prone to failure. Built to frustrate. A real marriage tester. Mine came new with a known factory defect. Fortunately, the repair tech turned out to be a Mr. Carlson's Lab fan and we got along fine. He clued me in to some other common failure points so I'm all set for the next time.