Thank you for sharing this video with us. It just goes to show that while the product may bear the name of a well known manufacturer on the outside the workings inside may be from a totally different company!

@michaeldranfield7140

6 ай бұрын

Its a bit of a shame as I bet they will still change extortionate prices for the new ovens .

@paul-c7541

5 ай бұрын

@@michaeldranfield7140 Of course they will, happy days for the bean counters.

Another classic case of the switch mode supply replacing the trusty power transformer.

@michaeldranfield7140

6 ай бұрын

Strange how they have reverted back to a transformer though , maybe its cheaper to make a transformer now ?

@user-uc5vr8le7y

6 ай бұрын

@michaeldranfield7140 Possibly. Could have something to do with the supply of silicone over the past few years.

@aga5897

6 ай бұрын

@@michaeldranfield7140 MOTs are mostly iron with aluminium windings, so they're much cheaper than ever before. The coils look like copper - just scrape away the surface and be greeted with shiny silver.

Looking forward to a follow up on this. I have a Panasonic inverter microwave myself.

@michaeldranfield7140

6 ай бұрын

Next few weeks I should have it ready .

We've used a cheap (just two knobs) Chinese microwave for 20 years and it just keeps on going. Who can compete with that? This might sound crazy but maybe the Chinese last longer than Panasonic nowadays.

@6AK5W-JAN

6 ай бұрын

Its not Chinese vs Panasonic that is the difference, its transformer vs SMPS. Transformers are reliable and last for decades, whereas high voltage SMPSes are fragile and fail within years. I remember when it was normal for microwaves to last decades. They all had steel transformers. People used to have microwaves that were inherited from their parents.

@michaeldranfield7140

6 ай бұрын

the thing is something very old will last much longer because all though it may have been cheap years ago I will be of a much better build quality and much better parts, the stuff they produce now is more or less disposable , just not designed to last many years .

The insides of that Neff microwave, looks the same as the insides of my £50 2005 Hinari from Argos! ... 19 years old, and still going strong! Just like my £199.99 2005 Candy washing machine from Argos!

I got out of repairing microwave ovens in the 1990s just as Panasonic were releasing their new "Inverter" type units. I remember looking at the inverter board of one which had blown up and thinking then that the idea was crazy. Semiconductors and high voltage / current don't play nicely together.

@michaeldranfield7140

6 ай бұрын

to be fair though the inverter boards have stood the test of time , I remember in the 90s when I was a sharp dealer we were shown a prototype on a sharp training course and told this would be the future , strangely enough though sharp never produced any over with a switched mode psu , in the UK anyway so I dont know why .

@PlatypusPerspective

6 ай бұрын

@@michaeldranfield7140 It took Sharp quite a while to get inverters online - in Australia they converted the entire model range to inverter. We started seeing a few for repair in the final years of my working life, under warranty the inverters were not a repair item, we would RMA the inverter module to SCA (Sharp Corporation of Australia) for exchange on their rework program.

@Indiskret1

6 ай бұрын

I bought a Panasonic microwave oven in the late 1990's, Inverter-type. It still works to this day, even the incandescent bulb inside (big thing with long filament, looks like for a very old projector). The white plastic case has yellowed though, so it looks a bit off. Edit: About quality from the past, I bought a cooler/freezer at the time, Swedish brand (Cylinda) but made in Denmark by Vestfrost. Standard model, nothing fancy at all. Still works to this day. I had to change the old typ capillary thermostat for the refrigerator part after 6 years, corroded away, new part was dipped in plastic. 25+ years this year. Practically unheard of if you buy newer stuff, which too often fails far sooner. Many later Cylinda were made by Turkish Arcelik, and they among other things managed to use untreated iron tubing for the condenser coils, så ALL those refrigerators failed within 3-5 years, first symptoms inside filling up with brown rust! Crazy, but true.

@PlatypusPerspective

6 ай бұрын

@@Indiskret1 The Series 1 Panasonics released in 1998 were manufactured in the US, the white plastic did go yellow over time. There were also some paint issues where the door pulled paint off the front mullion the first time it was opened. But they were very reliable. Here in Australia, I'm pretty sure they didn't have the tubular halogen floodlight style lamps, they were expensive to replace and with 240V mains here rather than 120V (so thin filaments), the halogens were rather delicate and prone to short life. (Some Sharp convection ovens used them since they handled heat well, but people didn't like having to replace them.) The US Panasonic models weren't manufactured for that long - divisions within Panasonic used to bid for production allocation and for the next model run the Chinese arm PHAMOS won the bidding.

Now you got my attention when you said IGBTS breakdown over time (with use I am guessing) as I have often wondered this myself. I repair a lot of Yamaha Power amps with IGBTs switch mode PSUs and I never see any reason why the IGBTs in them are always blown but the rest of the amp is working just fine when the PSU is repaired. This might explain the reason. Just the way they are made makes them go bad over time!

@michaeldranfield7140

6 ай бұрын

Yes, it was a very interesting and quite lengthy document detailing aging of a Igbt and it's failure mechanisms and the conclusion was a definitive degradation of the substrate of the device after prolonged use, eventually leading to failure, this is what prompted me to buy those 5 used Igbt s to do some comparative tests against a new device, however my simple tests all gave a pretty much identical results, the university were using x ray to examine the internal structure, like you I have replaced Igbt s with no other parts required which seems to suggest that they do degrade with use.

Did you check Mouser, Newark, or Digikey? They receive the products directly from the manufacturer. They have procedures in place to protect their supply chain so as to avoid fake and counterfeit products.

@cerulyse

6 ай бұрын

They are Panasonic only chips in a lot of of cases I think I can't imagine why they do that lol

@michaeldranfield7140

6 ай бұрын

Yes , checked all these , these transistors have been out of production for a long time hence the big fake market .

Very insightful - thanks. The very first appliance I bought when I entered the "real world" when I started working and my rented flat didn't have a microwave was a bog standard x-former Panasonic - it's been going 20+ years now but the inside is starting to rust under the wheels of the turntable - my parents replaced their old style microwave/grill with an inverter type about a decade ago and haven't had any issues (yet) - the appeal for me is the power control as we have PV/battery so being able to control the power would be useful, albeit not at the expense of reliability!

Midea is pronounced MAY-DEE in Mandarin. It is a big brand in China and considered reasonable quality for the price. We have lots of their products here in NZ and they seem to be ok mid range products. My Panasonic microwave has just started tripping my breaker when I pressed start last night. I guess it's gonna be a shorted IGBT and destined for the recyclers. Oh well. It was a roadside freebie and I got about 2 years from it, so I'm fine with it.

@michaeldranfield7140

6 ай бұрын

Many thanks for that , I wouldn't throw away your oven just yet , many different things can trip a breaker , water in the turntable motor is a very common cause .

@tenmillionvolts

6 ай бұрын

@@michaeldranfield7140 Yeah, I'll still diagnose it first. The turntable motor has always rotated when the door is open. I never bothered fixing that, so it is still rotating normally. I can program in the cooking time but as soon as I hit start, the breaker trips.

@tenmillionvolts

6 ай бұрын

@@michaeldranfield7140 Pulled my board out. It looks to have two IGBTs (high and low side?). Both measure shorted. I guess it's time to take her to the recyclers.

@interstat2222

5 ай бұрын

Midea has the Toshiba microwaves and appliances license in Europe. They also make decent fridges. Haier is another decent Chinese one who now own ex Italian brands Candy and Hoover. China not to be sniffed at anymore.

Thank you for the great video

@michaeldranfield7140

6 ай бұрын

No problem , many thanks for watching .

One of the bags says GT60N321. Digikey lists Toshiba GT60N321(Q), it is obsolete. However they give some of the specifications, this should help to find a substitute. Do you have any other part numbers?

@michaeldranfield7140

6 ай бұрын

I am not sure what the Q means at the end as I didn't find this on the data sheet , but yes this is the problem , the device is old and went out of production quite a while ago , hence the big market in fake parts .

Hi Michael I too have an integrated Neff microwave and was wondering what I would do if it failed, so will be looking forward to your Mosfet replacements. I find it’s normally the magnetron that fails with the cheaper microwaves, I think the caps failing is pretty rare, but then I may only repair 6-7 a year. Love your repair videos

@michaeldranfield7140

6 ай бұрын

Many thanks for that , keep watching in the next few weeks or so .

Hello, Panasonic for a long while use the non inverter tech in their base model microwave but they do still use inverters in the rest of their model range. The inverter they use is quire robust, id say we get more blown bulbs with melted DU PCB's than failed inverters. Wierdly i had a couple of failed inverters where the IGBT was short but the bridge rectifier was fine!

@michaeldranfield7140

6 ай бұрын

the bulb , yes you have to watch out for that one , bulb blows the pcb fuse that flashes over to the micro and writes the oven off as the micro is now no longer available .

always interesting to watch

@michaeldranfield7140

6 ай бұрын

Many thanks for that .

I would be pretty upset to find that my expensive Neff microwave contains a £50 no name Chinese chassis! I was given a Panasonic inverter microwave a few years ago, luckily has given no problems.

@sw6188

6 ай бұрын

Brand names mean nothing these days. Companies are incestuous and will put any name on something, regardless of who made it just to sell it. It used to be that once upon a time you could trust an appliance made by a certain company, but these days it's likely the company just gets cheap china junk with their logo and name on it.

@michaeldranfield7140

6 ай бұрын

Same here but I guess it had to happen , about a year ago I had in a industrial microwave in , made by Buffalow and that was the same , gone over to a Chinese chassis .

@kevvywevvywoo

6 ай бұрын

buffalo are are brand of Nisbets Catering Wholesalers, most buffalo stuff is made in china and they use the brand on alsorts of things for caterers

old transformer microwaves are much more reliable but weighs a ton and simpler to fix

@michaeldranfield7140

6 ай бұрын

Of course , the transformer microwave is largely unchanged technology from when they first came out .

Not nice to get something and it is a cheap copy . Good on you Michael for finding substitutes . Hope all goes well Cheers

@michaeldranfield7140

6 ай бұрын

I suppose it had to happen, just like everything else is badge engineered these days.

@Tegelane5

6 ай бұрын

Atleast one could get spares for them now.

Any component that meets or exceeds the original parameters is fit for replacing an original. A replacement IGBT, as an example, can be replaced with any other that matches or exceeds the original collector current and collector-emitter voltage, matches gate capacitance and total charge as close as possible. The emitter-collector max drop is of less importance and TDP should be equal or exceed OEMs. There are advances even in discreet semiconductors. Look up reputable sellers for original parts with warranty. I can recommend a couple if you're from the EU.

@michaeldranfield7140

6 ай бұрын

substituting an IGBT is not something I have ever done before , I have always used the correct part , but in this case its almost impossible to get as panasonic no longer have these , I was lucky to find a company with some old stock but I dont think that will happen again . The gate capacitance of the original part is very high no doubt due to the size of the device so its going to be very difficult to closely match this part , but as I understand it one with a lower gate capacitance will turn on quicker .

6 ай бұрын

@@michaeldranfield7140 you can substitute with lower gate charge. It will be fine as these are not self oscillators and it will only be easier on the driving totem. That is one of the advantages of newer transistors. And you could also increase gate dampening (resistor and ferrite bead) to avoid hf ringing. But for that you should carefully scope the gate slope and collector current to avoid any unnecessary lingering in the linear region. But in my opinion... I'd just throw in any beefy-enough igbt. Fakes are everywhere. Recently had a batch of 20 mosfets blow on me at 1/4th of the rated specs... And I should've known as they cost 1/3rd of OEMs =))

@michaeldranfield7140

6 ай бұрын

Many thanks for that , I will come back with another video soon .@

@kevvywevvywoo

6 ай бұрын

some IGBTs have integral inverse fast diodes, some do not, so dont fit one without a diode when the circuit needs one! Big bang!

6 ай бұрын

@@kevvywevvywoo I guess that should be obvious. But nowadays, pretty much all sport integrated fast diodes.

Midea makes all sorts of stuff. For example IKEA:s large cooler/freezer "Vinterkall" for a lot of money, is cheapo made by Midea.

@michaeldranfield7140

6 ай бұрын

I have no doubt I will be seeing more of the Midea stuff then .

O.k. most Microwave here in Australia use that type of system even Panasonic. Now days the inverter types are coming infrom China. I use to only have to repair the magnetron as they were made here so caps where good.

@michaeldranfield7140

6 ай бұрын

Its a wonder the Chinese have not been replicating the inverter boards as yet !

@chuxxsss

6 ай бұрын

@michaeldranfield7140 Well, the cheap microwaves here from kmart now have your system. I'm them.

That Neff looks very similar in build the my Cuisinart here in the states even down to the same Mag used. I still like the heavy transformer ovens, they've gotten pretty reliable over the years. On the flip side the Panasonic's are easier to move around.

@michaeldranfield7140

6 ай бұрын

Quite possible that the same oven appears with different names in different country's, the transformer ovens are much easier to repair due to the virtually unchanged design since they first came out .

@andrew_koala2974

6 ай бұрын

@@michaeldranfield7140 The plural of country is countries NOT country's

I took a trip to my local Curry’s the other day and couldn’t help noticing that pretty much all of the microwaves steel casings were identical (vents/pressings) all exactly the same with different plastics on the front. Whether it’s Panasonic, Sharp through to Morphy Richards, all the casings are identical. Has it got that way now where most microwaves are made by one manufacturer like Vestel with their TVs?

As soon as I saw the front of that Neff microwave I started typing this reply. And was about to say the most recent Bosch/Neff Microwaves are made by Midea who make most of the world's microwaves. Im not sure if the higher models are though as they look a bit different. I'm not familiar with Neff's model naming but Bosch has 2/4/6/8 etc series.

CORRECTED EDITED FORMATTED TEXT ; NEFF microwave ovens use to be made by PANASONIC and used the PANASONIC ; inverter - where the high voltage is generated by a switch mode power ; supply rather than an iron core mains transformer . ; Although from the outside this looks just like the previous model ; there was a nasty surprise lurking inside !

That looks like the 6 yerar old £80 cheapo MW that my daughter had. The display would hang up and the controls would not work. I you left it off for a while it worked for 5 mins then it would hang up. I did a quick check on caps and power supply, all seemed ok. I assumed it was the controller. It's now at the dump in the section reserved for new looking white goods but faulty.

@michaeldranfield7140

6 ай бұрын

True , I see loads of brand new looking white goods at out local tip, trouble is you cant get them !

@triodehexode

6 ай бұрын

@@michaeldranfield7140 Not like the good old days. I used to know the man at the dump in the 70s early 80s.

Have just used a substitute IGBT in another product and it seemed to go well so like others here I'd suggest trying a modern equivalent. Don't know what the operating frequency of these ovens are but if not too high maybe gate capacitance is not so much of a problem.

@jonathaneastwood2927

6 ай бұрын

2450mhz

@hoverbovver

6 ай бұрын

I was talking about the switching frequency of the IGBT, which is likely around 20kHz and not the microwave frequency.

So Neff is now just a brand on whatever things from China, and not the noble German manufacturer it once was. I've heard of Midea, they are are large manufacturer of domestic products, like HVAC, washing machines, microwaves. induction-cookers, rice-cookers, etc.

@sw6188

6 ай бұрын

Many things now are just "names" on china appliances. Here in NZ we had a famous appliance company called Fisher and Paykel. They started here in 1934 and made a wide range of things from washing machines to fridges and dryers. They were known for their quality. In 2012 they sold out to Haier of China, and now the appliances they sell here are mostly chinese junk with the Fisher and Paykel name and logo on them. Once upon a time you could find quality with a name such as Neff - as you say, they were a good German brand. Not so much these days.

@michaeldranfield7140

6 ай бұрын

although branded Neff they were made by Panasonic so not such a big deal as Panasonic was once a high end brand but it would appear they have gone the same as everyone else , just get it made as cheaply as possible to give the manufacture the biggest profit .

@michaeldranfield7140

6 ай бұрын

@@sw6188 This is what I tell people , paying much more money no longer guarantees it will last any longer so you might as well just buy a cheap one .

@sw6188

6 ай бұрын

@@michaeldranfield7140 Yes, and the people were victorious! They got what they asked for which was cheaper goods. No one wanted to pay more - they all wanted to pay less. Well, now they are paying less, a lot less - and getting a piece of junk that reflects the low price they are paying. Those same people will now complain that the items they buy don't last or they keep breaking down. You can't please them.

@andrew_koala2974

6 ай бұрын

​@@michaeldranfield7140 I have 4 Microwave ovens at home - One came from a Mosque - and given to me as they purchased a new one. Another PANASONIC found by the Kerb-Side store (That has been repaired ) another PANASONIC inverter MW I saw on the patio of a customer who called and wanted his SONY TV repaired - I asked him about the Microwave oven - He said "" It's going to recycling - The display does not work " He let me take it -- Took me half an hour to fix Another MW I purchased for AU $200 (Chinese made) I only bought it because it also operated as a toaster oven and an Air-Fryer - I also switch it OFF at the wall socket when not in use. So it is never ON continuously 24/7 It is kept clean inside -- I did notice however corrosion appearing around the exhaust vent. It would not be justified to send the case to have it powder coated. As the corrosion is minimal - I m not worrying about it - should it become worse - I will remove the cover - remove the corrosion and spray it with Black Epoxy Paint

That must be incredibly frustrating to spend quite a while fault finding an appliance only to have fake parts being installed & still not working.. it would make you scratch ya head a bit.

@michaeldranfield7140

6 ай бұрын

I got the money back for the fake supplied from a distributor, this is a huge problem now though fake parts , I would say most of the stuff sold on the internet is fake but unless you know how to spot a fake you wont know its fake until it blows again, quite possibly causing more damage that you had to start with .

Hi Michael - I hope your proposed test works well because I have two combo flat-bed Panasonics which we use every day and I'm banking on you being able to fix them when they eventually break down! This particular model, whilst absolutely brilliant, is sadly no longer available! Great video again.

@michaeldranfield7140

6 ай бұрын

Fingers crossed it should be ok , however there are different inverter boards used , this will cover the earlier version , then I will look into the later board as parts for these are also no longer available .

I bought my Sharp in 2006 and it's still working great. Sorry Sharp ! But I probably will buy another Sharp.

@michaeldranfield7140

6 ай бұрын

I still have a sharp at home from the mid 90 s , you might have a soft spot for sharp but did you know Sharp no longer exists ? they closed down many years ago and sold the brand name off , UMC produce sharp branded TV s and Vestel produce the Sharp branded microwaves .

@robertroe1956

6 ай бұрын

Also have a + - 30 year old Sharp Carousel. Brilliant

@andrew_koala2974

6 ай бұрын

SHARP was sold to CHINA in 1989

@andrew_koala2974

6 ай бұрын

@@robertroe1956 Note that the name is SHARP and not Sharp. Pay attention to detail. Make sure the brain sees exactly what the eyes are L00KING at. Unfortunately you were programmed to be a ZOMBIE and you do not realize it. ZOMBIES have eyes but cannot see - ears and cannot hear

That would explain why with the replacement for the lady giving you the donor microwave she said it was cheaper than her original. Cheaper yes, Panasonic no, quality dubious.

@michaeldranfield7140

6 ай бұрын

exactly , wonder how she will feel in another 18 months time .

So all electric cars use IGBTs in the power delivery stages - makes me wonder how long they will last before giving up the ghost - since IGBTS (and most semiconductors) almost always fail shorted, I do hope they have decent protection in place as usually the "fuse" is always just fine in most SMPS I repair!

@sw6188

6 ай бұрын

The IGBT in cars might last longer as they are dealing with comparatively lower voltages (but higher currents).

@mattsan70

6 ай бұрын

@@sw6188 I think its the heat cycling and vibration that's killing them according to what I have read so far. So higher currents will kill them quicker in this case.

@sw6188

6 ай бұрын

@@mattsan70 It's not something I have much experience with. All I know is that semiconductors and high voltage / current don't play nicely together! When I saw the Panasonic inverter boards when they first hit the market I remember thinking it was a crazy idea.

@michaeldranfield7140

6 ай бұрын

quite possibly , however there is a possibility they are better designed for a harsh environment , like a mil spec part .

Will replacing IGBT with MOSFET make it more durable? With the usual MOSFET 80N60

@michaeldranfield7140

6 ай бұрын

I don't know if this will be possible as the base /gate drive circuit will be different .

Random question: do you know how to silence the beep on microwaves? Got a Russell Hobbs RHM2362S. Can beeps be silenced through 'secret' key presses or only via physical modification inside?

@michaeldranfield7140

6 ай бұрын

if there is no mention of secret key strokes in the instruction book you could just take out the piezeo sounder off the control board .

@robertroe1956

6 ай бұрын

I tried that with a UPS, then it stopped working. I have no idea why. I put the speaker back then pushed some prestik in the speaker. Muffled the annoying beep nicely and you can still just hear it. (And much easier than taking out the speaker)

WoW ! i didn't know microwave oven inverter boards even existed ! Do they run the magnetron the same way as the good old MOT, i.e. 3kVDC + 3.6VAC for the heater ?

@PlatypusPerspective

6 ай бұрын

Same principle, low voltage for the heater, which is pulled negative as the cathode, but the inverter has somewhat different waveshape which peaks more towards 6kV for a 1200W or 1300W oven, Switching frequency of tens of kHz and the magnetrons are designed to have suitable characteristics for inverter drive.

I thought you was going find a rodent or large insects inside

@markcase11

6 ай бұрын

I had one full of cockroaches once, I didn't fix that one 😂

@michaeldranfield7140

6 ай бұрын

sorry , no , but I did have one in once with a dead mouse lying across the mains input board .

I've had three inverter "Pan o' Bangers" over the years, and always felt that the reliability was not all that good. I know I still have two duffers here, right now. One is a basic microwave only, and the other is an all singing, all dancing microwave, convector, grill combination. Now, I'm going to be having a clear out in the weeks ahead. If/when I find them, would you still be interested in them? I don't know what state they'll be in, but I can let you know as and when I turn them up. Interested?

@michaeldranfield7140

6 ай бұрын

Yes I would be very interested in some inverter boards, the model number of your combi would also be of interest as I have a nearley new one, well it was nearley new a couple of years ago! The control panel has blown up but there's no circuit diagram for it so I can't identify the parts that have blown, it's board only replacement but the customer didn't want to pay and gave it to me but it was far too good to scrap and not worth buying a new pcb.

@whitesapphire5865

6 ай бұрын

@@michaeldranfield7140 I will definitely let you know what I find as I dig my way through. The combi is a fairly old beast, all brushed stainless steel trim and polished stainless steel cabinet. The other is a plain white painted cabinet with plain white plastic control panel and door. Is it just the PCBs you want? Or the the entire ovens?

@michaeldranfield7140

6 ай бұрын

@@whitesapphire5865 Just the PCB should be fine thanks .

@whitesapphire5865

6 ай бұрын

@@michaeldranfield7140 In that case, I'll take them out as and when I find them, then they can be boxed up for posting. Do you want the magnetrons as well?

the number of microwave OEMs is getting fewer and fewer, I heard somewhere that the biggest microwave oem in the world is Galanz, who make 90-something percent of the world's microwaves. Mine's a 28-year old panasonic. Made in uk. With a transformer. Never been fixed, all working. Bought it when I left home!!

@PlatypusPerspective

6 ай бұрын

Yes, when I was doing bench repairs, many small/mid size models of various brands were Galanz inside. Keep on with that Panasonic as long as you can. 🙂

"food rotator"

Do these "inverter" microwaves have any advantages over the conventional transformer types?

@PlatypusPerspective

6 ай бұрын

For the user, it is good to be able to have the oven actually run at a lower power output when heating or cooking something delicate. A standard microwave reduces power by cycling between full power and off periodically (since it only has full power or off), which can sometimes overdo things during the full-on period. Setting 50% on an inverter actually runs continuously outputting half the power. Very low power outputs still have an on-off cycle. Defrosting in an inverter unit tends to be more refined than a standard unit. The inverter ovens are a bit more efficient in power consumption. An important factor from the manufacturing and distribution point of view is considerable reduction in weight. Since shipping is a big contributor to distribution costs, it can be either higher return to the manufacturer or lower cost to the end user if shipping costs are lower.

'Only £450 for a new one' lol. I think my current microwave oven cost about £20

@michaeldranfield7140

6 ай бұрын

It was a build in microwave they are much more expensive and don't forget your also paying a large premium for the name on the front .

@bigbasil1908

6 ай бұрын

@@michaeldranfield7140 I feel bad for people who have to buy certain brands because they don't want to feel they can be looked down on by others because of it lol

What about On semi FGA30N120FTDTU

@michaeldranfield7140

6 ай бұрын

I don't know off the top of my head as I'm at home now but that number sounds similar if not the same as I have already bought from RS , the package is different so it requires the drilling of another hole , I couldn't find anything suitable in the original package .

Great! Always enjoy your videos, Michael. Could anyone help, please? I recently bought a working 80s Sharp R-7100 microwave from an eBay business seller, who sent it at my request to someone I know who rebuilds Kenwood Chefs - I have two of his and they’re great - and other small appliances, plus PAT tests then. He’s agreed to look at it but admits he hasn’t serviced microwaves. Is there anything he should look out for? Is it a case of “if it ain’t broke, don’t fix it” and would it be OK to use without extensive examination and testing inside by someone experienced with microwaves? Is there anyone with microwave experience I can post it to who might be able to refurbish it? Many thanks. :)

@PlatypusPerspective

5 ай бұрын

The R-7100 is from an era when microwaves were built like little tanks and went until they stopped. If you want to confirm safety regarding microwave leakage, you should be able to find a workshop with a leakage detector, or your small appliance guy might be able to borrow one. Those units have a very tight door construction though, and I never found any with leakage apart from actual physical damage to the door. A general inspection for condition is what I would do first, particularly the black plastic "filler" piece around the inner edge of the door facing the mullion (the outward facing flat surface that the door closes against). The plastic insert is called the choke, and is part of the leakage prevention, the plastic is filled with magnetic powder. It should not be cracked or have any portion missing. The door should close cleanly and firmly, without being over-tight. If it's sloppy, there is adjustment inside on the latch assembly, accessed by removing the outer casing. I think the door hinge on those is a piano hinge, a light machine oil can be wicked in between the hinge segments to prevent squeaking or binding. Light application of silicone grease to the door hooks makes the latching action smoother. It's not a high powered oven, so overheating usually isn't a problem, but all the air circulation vents can be checked and cleaned of fluff/grease buildup. When the outer casing is removed, it can be seen if the fan blades and magnetron cooling fins are gunked up, and can be gently cleaned with long cotton tips moistened with alcohol. The fan motor would benefit from application of machine oil to the bearings, for the sintered bronze to absorb. If any of the magnetron cooling fins are getting bendy/warped or are loose and can be jiggled about, the magnetron isn't happy. But the lower powered ones can actually soldier on like that for some time before ceasing to work. The waveguide cover inside the oven cavity (silvery rectangular plate usually held in by one or two screws), should be replaced if it is very dirty/greasy or has black burnt patches. It's a mica or polycarbonate material that a MWO workshop will normally have bulk to cut from, a genuine part for that age is probably not going to be found. If the cover looks clean and sound (e.g. not half missing) it will be fine. If there is any paint missing (I don't think the 7100 had a stainless steel cavity), like on the cavity floor or mullion, and it has rusted or burnt (arcing) it might be feasible to touch it up with an enamel touch-up paint. If there is arcing/burning on the front mullion or door, that isn't good - this is also part of the leakage protection system. It may be able to be carefully cleaned up and a paint touch-up done. Sometimes this isn't successful and it arcs again through the new paint. Your small appliance guy should be used to applying standard electrical safety measures, remember a MWO also has very high voltage sections and avoid running the oven with the outer cover removed. If I think of anything else, I'll add it later.

@carlstock

5 ай бұрын

@@PlatypusPerspective Thank you so much for this incredibly detailed information. It has been well received by my appliance guy.

@PlatypusPerspective

4 ай бұрын

@@carlstock Glad to have been able to offer some help.

could you get those igbts from farnell or rs ?

@michaeldranfield7140

6 ай бұрын

Not the correct Toshiba device , they went out of production many years ago but I did get the replacements I am planning to use from RS .

Midea make a lot of low budget white goods (washing machines, dishwashers etc ) often the Currys own brand stuff Logik . Wonder what the Neff customer would think if he knew it was low budget Midea inside his microwave .

@sw6188

6 ай бұрын

People often get a shock these days when they find out their supposed "quality" name-brand appliance is just a cheap piece of chinese rubbish with a previously "good" name on it.

@andrew_koala2974

6 ай бұрын

What would the customer with the NEFF think if he knew it was low cost budget Midea inside his microwave ? NoIdea.

Did you say the client purchased a new microwave for £450 and thought it was cheep? They are about £75-100 for a basic one. Even the expensive ones do the same as the £75 ones - warm your food! I brought what i considered an expensive one at £279 a few years ago, but never have used any of the features (grill/oven/steamer) apart from throw a plate of food in and press start a couple of times to warm something up lol

@bigbasil1908

6 ай бұрын

My microwave cost about £20 in tesco. It does the job and has a halogen grill in it too.

@AnotherPointOfView944

6 ай бұрын

@@bigbasil1908 I twice bought a sub-£50 microwave from Tesco. Light failure within a a few weeks. Microwave dead within 6 months, both. Not great.

@michaeldranfield7140

6 ай бұрын

yes £450 but its a build in one which are much more expensive than just a stand alone microwave and don't forget your also paying a big premium for the name , which actually means nothing now , Couple of years ago I had a customer who paid something like £130 for a high end German brand of toaster, he brought it to me for repair , element had failed , underneath it said made in china , when I checked with my supplier no parts available, it was classed as a disposable item .so as you say , might as well just have bought a cheap one .

@michaeldranfield7140

6 ай бұрын

and some microwaves are now using LED light bulbs which are not available , I just fit an incandescent bulb .@@AnotherPointOfView944

@bigbasil1908

6 ай бұрын

@@AnotherPointOfView944 I've had my cheapo microwave for years lol.

Overheating killed mine I think. I bought a kit of IGBTs for a plasma, I haven't fitted them yet 🙄 people do appear to fix them. If you plug one of those Panasonics in to a wall meter it shows it pulses the power off an on much like one with a transformer lol

@PlatypusPerspective

6 ай бұрын

Poor cooling is a common contributor to short service life of an inverter. Ovens that are built into cabinets, sat in tight nooks or next to or above cooktops were frequent visitors to my workshop showing failed inverters. I started to notice it with the very first Series 1 Panasonic inverters when they first came onto the market, they were extremely reliable, but the failures we did start to see after about 18 months were all built-in units with inadequate air circulation.

@michaeldranfield7140

6 ай бұрын

unless your kit is a genuine manufacture. supplied repair kit I would check very carefully before fitting it does not contain fake parts .

@michaeldranfield7140

6 ай бұрын

@@PlatypusPerspective most common cause I find for poor cooling is the back vents get greased up in a kitchen and then dust sticks to blocking the air intake .

@PlatypusPerspective

6 ай бұрын

@@michaeldranfield7140 Yes, true. Even more so with commercial ovens, they came in dripping with grease and the intake filters totally clogged - both magnetrons cooked.

@michaeldranfield7140

6 ай бұрын

Funny you should say that , I have a 18 month old Samsung commercial oven in for repair , it looks to be virtually brand new and both magnetron's have failed but I waiting for the customer to get back from holiday and tell me the true story about this because there is something very odd , they claim to have bought it brand new but there are 3 screws missing out of the back so something does not ring true .@@PlatypusPerspective

i dont see why they went with an inverter, the traditional innards are far simpler and probably more reliable?

@michaeldranfield7140

6 ай бұрын

May be at the time it was cheaper to make an inverter than a iron cored transformer with expensive copper wire , however some transformer I have seen use aluminium wire that's just enamelled so it looks like copper .

@andygozzo72

6 ай бұрын

@@michaeldranfield7140 weird, though i do have a small hank of enamelled what i think is aluminium wire, but its not recent stuff, its probably 1950s or even older, 30s maybe , its certainly not copper, maybe steel or a resistance wire, never tested it in any way, got it as part of a job lot of enameled wire 20+ years ago..

If you get stuck for a microwave, i have a working Panasonic invertor turobake microwave, which i would be more than willing to loan and post to you. Gary

Michael it 'seems that Cheap Chinese, rubbish is everywhere these days.

@michaeldranfield7140

5 ай бұрын

True , everything you buy now is crap , had a new tap in the bathroom to replace the 26 year old one last summer , its broke already.

if they do go bad over time surely theyre a bad thing to use?

@michaeldranfield7140

6 ай бұрын

Heat cycling seems to degrade the internal structure of the device .

@andygozzo72

6 ай бұрын

@@michaeldranfield7140 heat cycling likely degrades most components, some commodore/MOS branded chips are notorious for failing due to 'age', sinclair ULAs fail due to heat....

😊😊😊😊😊😊

Can I send you my board to fix I’ll pay whatever mate

@michaeldranfield7140

3 ай бұрын

I would need the whole microwave to be able to test the board and make sure its not the magnetron that has caused the failure.

@theguys1051

3 ай бұрын

How could I get it to you

I had a microwave that stopped heating up (think it was an LG). Light would come on and it would run the timer etc but the food came out cold. I assumed that was a common symptom when the magnetron failed but sounds like it's not.

@PlatypusPerspective

6 ай бұрын

With an LG, yes magnetron failure would be a common cause. If it's not an inverter model, sometimes it's the HV rectifier or HV capacitor, all causes that blow the HV fuse and result in no heat. Occasionally there will be a failure of the HV fuse for no apparent reason.

@michaeldranfield7140

6 ай бұрын

No , don't just assume its the magnatron, it could be as simple as a bad connection on the filament terminals , as the heater draws something like 10 amps so any slight high resistance here will cause it not to heat up, other possibility are an aged high voltage fuse that just blows for no reason .

@PlatypusPerspective

6 ай бұрын

@@michaeldranfield7140 That was rather common in older Panasonic models especially the ones that used 4.8mm terminals instead of 6.5mm. If a Panasonic came in not heating the first thing you'd check for was discolored heater terminal insulator and crunchy noises when you jiggled the wire.

Oh wow what a nasty trick to play, all down to money and profit shame on them Nice insight Michael thank you 😊

@michaeldranfield7140

6 ай бұрын

Badge engineering has been with us a long time now so I guess it had to happen with the microwaves sooner or later .

@wisher21uk

6 ай бұрын

@@michaeldranfield7140 exactly Michael

used to be able to get old microwaves wash machines tv's from the tip, but they wont let you have anything like that now! put me out of business, as i used to recon the old washing machines & sell them on, MIDEA make cheap nasty washing machines & dishwashers in china, often branded up as currys essentials (logik), there better than vestal machines tho

@michaeldranfield7140

6 ай бұрын

Same here , as a kid I could go to the tip and just pick up stuff for nothing , it was the highlight of the week , a Sunday day out at the tip , then in later years people ran the tip and you had to pay them for stuff, these days the tips all seem to be run by the council and no one will let you take anything at all , which to me makes no sense because for the stuff I want I would pay them far more than they price they get for scrap .

@peterensinger1770

6 ай бұрын

when i was a kid, my next-door neighbour used to work at the local council tip he used to bring all sorts of electronic items home mostly radiograms and black and white tvs as well as record players for me to fix my first colour tv came from the tip my school mates were envious wiith me having a colour tv in my room at only 12 years old ...in those days the majority of people used to rent their tvs including my parents that was until i found another colour tv at the tip and repaired it. those were the days nowadays if you even look at the electronic items at the tip they say you can't touch them.

Drop a meesage to me