Panasonic microwave, blown inverter board transformer...

[Andrew]

Hi, I have an NN-A554W and the transformer on the inverter board has
blown. Microwave wouldn\'t start cooking so I ran it for a moment with
the cover off, transformer did a light and smoke display and now it
smells like fireworks.

I made sure the magnetron was discharged and between the two connections
I am getting 0 ohms, but I only have a basic multimeter. Between those
and the casing is open.

This microwave is at least 10 years old with a lot of use, so how likely
is it that the transformer has just gone by itself vs the magnetron or
the small mains input board dying and taking the transformer with it?

The other thing is that the part number of the inverter/transformer
board is A6645M304GP, and the magnetron is a 2M236-M42. A lot of other
models seem to use boards that look identical, but not exactly the same
part number. For example I have found a site saying that this magnetron
can be used with an A66454T05AP or F66454T07AP board, which do look the
same as mine, so are they just a different revision or something or are
the differences going to be bigger?

Even if I need exactly the same board, it looks like I could be chasing
a part that would work in many different models, even different brands,
if only I knew which one to look for (it seems there are no parts for my
model).

Am worried about replacing it and having the new one get instantly blown
up though.

Andrew

 

[Andrew]

On 2020-06-08 17:04, pfjw@aol.com wrote:

OK. On the one hand:

Purchase new Board: US$25 + shipping
Install New Board: 2 hours work

It all works: All good!

Magnetron is bad: Purchase new Magnetron for US$65 + shipping
Install new Magnetron: 2 hours work.

It wall works: 4 hours + US$90 + shipping.

On the other hand, a brand new 1,000 watt microwave: US$150, complete with warranty.

I admire your wish to reduce landfill, but I have to wonder at the investment in a 10 year old device that is heavily used by your own description.

Peter Wieck
Melrose Park, PA

Thanks. I would feel sad if I hadn\'t made an attempt. A new one would be
a bit more expensive though because it\'s an oven and grill combi. Hate
that it seems so simple to fix if only I could find the correct board to
plug in

Andrew

 

[pfjw@aol.com]

1 (800) 211-7262

I entirely understand that this Group exists so that individuals may discuss means-and-methods for doing pretty much anything at all in the hardest possible way, reaching for the least satisfactory results. And that includes reaching around the world for S.W.A.G., anecdotal experiences and arbitrary suggestions.

Rather than going to the Mother Ship and asking there.

Panasonic Customer Service number above.

Then: https://www.justanswer.com/sip/panasonic-help-24-7?r=ppc|ga|27|Tech-CE-SQR-Search-BMM|CE-Panasonic|&JPKW=%2Bpanasonic%20%2Bengland&JPDC=S&JPST=&JPAD=378934176681&JPMT=b&JPNW=g&JPAF=txt&JPRC=1&JPCD=&JPOP=&cmpid=2032112328&agid=76054807163&fiid=&tgtid=kwd-807471796533&ntw=g&dvc=c&gclid=CjwKCAjw5vz2BRAtEiwAbcVIL4IpznzJVHkSJM0UAa4rerYc42_ibvjnkdsd_EkpKG39BsihtcQHsBoC1VcQAvD_BwE

Peter Wieck
Melrose Park, PA

 

[Adrian Caspersz]

On 09/06/2020 13:19, pfjw@aol.com wrote:

> Then: https://www.justanswer.com/sip/panasonic-help-24-7?r=ppc|ga|27|Tech-CE-SQR-Search-BMM|CE-Panasonic|&JPKW=%2Bpanasonic%20%2Bengland&JPDC=S&JPST=&JPAD=378934176681&JPMT=b&JPNW=g&JPAF=txt&JPRC=1&JPCD=&JPOP=&cmpid=2032112328&agid=76054807163&fiid=&tgtid=kwd-807471796533&ntw=g&dvc=c&gclid=CjwKCAjw5vz2BRAtEiwAbcVIL4IpznzJVHkSJM0UAa4rerYc42_ibvjnkdsd_EkpKG39BsihtcQHsBoC1VcQAvD_BwE

\"JustAnswer LLC is in no way associated with Panasonic. All other brands
and trademarks are the property of their respective owners who in no way
endorse JustAnswer LLC.\"

--
Adrian C

 

[Adrian Caspersz]

On 09/06/2020 13:19, pfjw@aol.com wrote:

> Then: https://www.justanswer.com/sip/panasonic-help-24-7?r=ppc|ga|27|Tech-CE-SQR-Search-BMM|CE-Panasonic|&JPKW=%2Bpanasonic%20%2Bengland&JPDC=S&JPST=&JPAD=378934176681&JPMT=b&JPNW=g&JPAF=txt&JPRC=1&JPCD=&JPOP=&cmpid=2032112328&agid=76054807163&fiid=&tgtid=kwd-807471796533&ntw=g&dvc=c&gclid=CjwKCAjw5vz2BRAtEiwAbcVIL4IpznzJVHkSJM0UAa4rerYc42_ibvjnkdsd_EkpKG39BsihtcQHsBoC1VcQAvD_BwE

\"JustAnswer LLC is in no way associated with Panasonic. All other brands
and trademarks are the property of their respective owners who in no way
endorse JustAnswer LLC.\"

--
Adrian C

 

[pfjw@aol.com]

Doesn\'t change the fact that it is a source for information. Further, it suggests that it is geared towards older equipment.

Peter Wieck
Melrose Park, PA

 

[pfjw@aol.com]

Doesn\'t change the fact that it is a source for information. Further, it suggests that it is geared towards older equipment.

Peter Wieck
Melrose Park, PA

 

[Andrew]

On 2020-06-09 13:19, pfjw@aol.com wrote:

1 (800) 211-7262

I entirely understand that this Group exists so that individuals may discuss means-and-methods for doing pretty much anything at all in the hardest possible way, reaching for the least satisfactory results. And that includes reaching around the world for S.W.A.G., anecdotal experiences and arbitrary suggestions.

Rather than going to the Mother Ship and asking there.

Panasonic Customer Service number above.

Then: https://www.justanswer.com/sip/panasonic-help-24-7?r=ppc|ga|27|Tech-CE-SQR-Search-BMM|CE-Panasonic|&JPKW=%2Bpanasonic%20%2Bengland&JPDC=S&JPST=&JPAD=378934176681&JPMT=b&JPNW=g&JPAF=txt&JPRC=1&JPCD=&JPOP=&cmpid=2032112328&agid=76054807163&fiid=&tgtid=kwd-807471796533&ntw=g&dvc=c&gclid=CjwKCAjw5vz2BRAtEiwAbcVIL4IpznzJVHkSJM0UAa4rerYc42_ibvjnkdsd_EkpKG39BsihtcQHsBoC1VcQAvD_BwE

Peter Wieck
Melrose Park, PA

Thanks

Andrew

 

[Andrew]

On 2020-06-09 13:19, pfjw@aol.com wrote:

1 (800) 211-7262

I entirely understand that this Group exists so that individuals may discuss means-and-methods for doing pretty much anything at all in the hardest possible way, reaching for the least satisfactory results. And that includes reaching around the world for S.W.A.G., anecdotal experiences and arbitrary suggestions.

Rather than going to the Mother Ship and asking there.

Panasonic Customer Service number above.

Then: https://www.justanswer.com/sip/panasonic-help-24-7?r=ppc|ga|27|Tech-CE-SQR-Search-BMM|CE-Panasonic|&JPKW=%2Bpanasonic%20%2Bengland&JPDC=S&JPST=&JPAD=378934176681&JPMT=b&JPNW=g&JPAF=txt&JPRC=1&JPCD=&JPOP=&cmpid=2032112328&agid=76054807163&fiid=&tgtid=kwd-807471796533&ntw=g&dvc=c&gclid=CjwKCAjw5vz2BRAtEiwAbcVIL4IpznzJVHkSJM0UAa4rerYc42_ibvjnkdsd_EkpKG39BsihtcQHsBoC1VcQAvD_BwE

Peter Wieck
Melrose Park, PA

Thanks

Andrew

 

[Cydrome Leader]

pfjw@aol.com <peterwieck33@gmail.com> wrote:

OK. On the one hand:

Purchase new Board: US$25 + shipping
Install New Board: 2 hours work

It all works: All good!

Magnetron is bad: Purchase new Magnetron for US$65 + shipping
Install new Magnetron: 2 hours work.

It wall works: 4 hours + US$90 + shipping.

On the other hand, a brand new 1,000 watt microwave: US$150, complete with warranty.

I admire your wish to reduce landfill, but I have to wonder at the investment in a 10 year old device that is heavily used by your own description.

Peter Wieck
Melrose Park, PA

What is the reliability difference, if any between the classic
transfomer/diode/capacitors and the fancy inverter ovens?

 

[Cydrome Leader]

pfjw@aol.com <peterwieck33@gmail.com> wrote:

OK. On the one hand:

Purchase new Board: US$25 + shipping
Install New Board: 2 hours work

It all works: All good!

Magnetron is bad: Purchase new Magnetron for US$65 + shipping
Install new Magnetron: 2 hours work.

It wall works: 4 hours + US$90 + shipping.

On the other hand, a brand new 1,000 watt microwave: US$150, complete with warranty.

I admire your wish to reduce landfill, but I have to wonder at the investment in a 10 year old device that is heavily used by your own description.

Peter Wieck
Melrose Park, PA

What is the reliability difference, if any between the classic
transfomer/diode/capacitors and the fancy inverter ovens?

 

[Adrian Caspersz]

On 15/06/2020 09:30, Cydrome Leader wrote:

What is the reliability difference, if any between the classic
transfomer/diode/capacitors and the fancy inverter ovens?

The Inverter model reliably makes a louder sound on expiry?

I\'d bet the fancy Inverter design is to get the price down, cost of
copper and weight etc. The chief reason for a SMPS.


--
Adrian C

 

[Adrian Caspersz]

On 15/06/2020 09:30, Cydrome Leader wrote:

What is the reliability difference, if any between the classic
transfomer/diode/capacitors and the fancy inverter ovens?

The Inverter model reliably makes a louder sound on expiry?

I\'d bet the fancy Inverter design is to get the price down, cost of
copper and weight etc. The chief reason for a SMPS.


--
Adrian C

 

[pfjw@aol.com]

It is all in accordance with what you want.

An \"inverter\" microwave modulates the output of the magnetron directly. So, 50% setting means the magnetron is putting out 50% of its full capacity, but all of the time. With a conventional microwave, that is achieved by running the magnetron in duty/rest cycles. 100% for 50% of the time 0% for 50% of the time. Inverter-based microwaves become far more flexible and therefore far more useful.

Re Reliability: Our present Panasonic (inverter) is about 6 years old and gets moderate use. It replaced a 16 year old multi-voltage BEAC we purchased in Saudi, that is now still in minimal use by a neighbor in his garage workshop. We keep our devices clean, make sure they get enough air circulation, and, heaven forfend, even clean the vents regularly!

Basic care-and-feeding is becoming a lost art.

Peter Wieck
Melrose Park, PA

 

[pfjw@aol.com]

It is all in accordance with what you want.

An \"inverter\" microwave modulates the output of the magnetron directly. So, 50% setting means the magnetron is putting out 50% of its full capacity, but all of the time. With a conventional microwave, that is achieved by running the magnetron in duty/rest cycles. 100% for 50% of the time 0% for 50% of the time. Inverter-based microwaves become far more flexible and therefore far more useful.

Re Reliability: Our present Panasonic (inverter) is about 6 years old and gets moderate use. It replaced a 16 year old multi-voltage BEAC we purchased in Saudi, that is now still in minimal use by a neighbor in his garage workshop. We keep our devices clean, make sure they get enough air circulation, and, heaven forfend, even clean the vents regularly!

Basic care-and-feeding is becoming a lost art.

Peter Wieck
Melrose Park, PA

 

[John Robertson]

On 2020/06/08 7:44 p.m., Mike S wrote:

On 6/8/2020 9:04 AM, pfjw@aol.com wrote:
OK. On the one hand:

Purchase new Board: US$25 + shipping
Install New Board: 2 hours work

It all works: All good!

Magnetron is bad: Purchase new Magnetron for US$65 + shipping
Install new Magnetron: 2 hours work.

It wall works: 4 hours + US$90 + shipping.

On the other hand, a brand new 1,000 watt microwave: US$150, complete
with warranty.

I admire your wish to reduce landfill, but I have to wonder at the
investment in a 10 year old device that is heavily used by your own
description.

Peter Wieck
Melrose Park, PA

Farberware Classic 1.1 cu. ft .1000-Watt Microwave Oven $99.99
Farberware Classic 0.9 cu. ft. 900-Watt Microwave Oven $89.99

https://www.hsn.com/shop/50-99-ranges-and-microwaves/ho0514-6664

The question is, how long would these MWs last under the same usage as
the original Panasonic? I suspect perhaps 5 years...so repairing a
machine that lasted 10 years, might cost $100 - and give it another ten
years. Vs. replacing it with a cheaper design that may last 1/2 the
time? Is that really a better deal? Plus you have saved landfill.

John :-#)#

 

[Jeff Liebermann]

On Mon, 8 Jun 2020 00:02:34 +0100, Andrew <andy29.uk@gmail.com> wrote:

Hi, I have an NN-A554W and the transformer on the inverter board has
blown. Microwave wouldn\'t start cooking so I ran it for a moment with
the cover off, transformer did a light and smoke display and now it
smells like fireworks.

Impressive. I know how you feel:
<http://www.learnbydestroying.com/jeffl/pics/drivel/#burned-yam.jpg>
That\'s what happened when I cooked a yam (potatoe) for 16 minutes
instead of 6 minutes. It was glowing bright red inside just before I
opened the door. The inside of my Panasonic NN-S533WF (Sensor 1300w)
microwave oven changed from white to yam colored. I tried to clean
it, but the yam color is permanently baked into the paint. The S/N
label says made in 2003. I think I received it as a present in 2005,
making it 15 years old. It works as well today as it did in 2005 with
no change in output level. That\'s one of the benefits of an inverter
oven.

I made sure the magnetron was discharged and between the two connections
I am getting 0 ohms, but I only have a basic multimeter. Between those
and the casing is open.

Try measuring again with a much better ohmmeter or preferably an ESR
meter, which will measure resistances below 1 ohm. The two terminals
on the magottron are the filament wires. Less than 1 ohm is typical
and is easily mistaken for a short circuit.
\"Magnetron Test for Opens, shorts or Insufficient Power\"
<https://www.microwavespecialties.com/pdfs/E10-2010-06%20Mag%20Test%20Bulletin.pdf>
The instructions are for a commerical oven, which may have more than
one magnetron inside, but the methods are the same for a home
microwave oven with only one magnetron.

This microwave is at least 10 years old with a lot of use, so how likely
is it that the transformer has just gone by itself vs the magnetron or
the small mains input board dying and taking the transformer with it?

Near zero. I haven\'t repaired too many microwave ovens and only one
inverter oven. Mostly, what I find are (in order of frequency):
1. Blown high voltage diodes.
2. Blown high voltage capacitor.
3. Blown thermal protection fuse.
4. Filthy and intermittent door interlock switch.
5. Low magentron output or dead magnetron.
I would guess I\'ve fixed about 20 mw ovens and have yet to see a blown
high voltage transformer. If the enamel coating on the torroid are
discoulored from overheating, you might have a problem with the
transformer. If it looks normal, it\'s something else.

You might want to try searching on YouTube for videos on how to
diagnose and repair microwave ovens. This looks like a good start:
<https://www.youtube.com/watch?v=hBJJU4ZRh7U>

The other thing is that the part number of the inverter/transformer
board is A6645M304GP, and the magnetron is a 2M236-M42. A lot of other
models seem to use boards that look identical, but not exactly the same
part number. For example I have found a site saying that this magnetron
can be used with an A66454T05AP or F66454T07AP board, which do look the
same as mine, so are they just a different revision or something or are
the differences going to be bigger?

What you\'re seeing are differences in part number because the
manufacturer sourced their magnetron from multiple (Chinese) sources.
Each source has a different part number, but are functionally and
mechanically identical. The NN-A554W is a 1000 watt oven, so any 1000
watt magnetron that mechanically fits is likely to work.

Even if I need exactly the same board, it looks like I could be chasing
a part that would work in many different models, even different brands,
if only I knew which one to look for (it seems there are no parts for my
model).

No parts? Google is your friend:
<https://www.google.com/search?q=NN-A554W+oven+parts>
Hmmm... are you in the UK? The Panasonic model number seems to be a
UK only 230VAC oven?

Am worried about replacing it and having the new one get instantly blown
up though.

Well, if you want an exact replacement, it would helpful if you would
supply the full model number. Is it NN-A554WB or NN-A554WF ?

If you have no clue what you\'re doing, and are lacking in basic test
equipment, I would recommend:
1. Checking the magnetron with an ohms guesser.
2. If ok, replace the Hi-V diodes and Hi-V capacitor.
3. If that doesn\'t fix it, don\'t replace the magnetron. Instead by a
replacement inverter board. It\'s one of these:
<https://www.kitchenwareonline.com/panasonic-microwave-oven-hv-inverter-m3ffzz000bp-c2x13938345>
<https://www.kitchenwareonline.com/panasonic-hv-inverter-for-microwave-ovens-z606yba00gp-c2x15619538>
4. If that doesn\'t fix it, it MIGHT be the magnetron, but I doublt
it. Magnetrons usually fade away slowly, where cooking takes longer
and longer, until it doesn\'t cook. It does not die suddenly or belch
fire. If you bought a replacement board, you\'ve probably spend more
on the repair than the oven is worth. I suggest you cut your losses
and just buy a new oven.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Mon, 8 Jun 2020 00:02:34 +0100, Andrew <andy29.uk@gmail.com> wrote:

Hi, I have an NN-A554W and the transformer on the inverter board has
blown. Microwave wouldn\'t start cooking so I ran it for a moment with
the cover off, transformer did a light and smoke display and now it
smells like fireworks.

Impressive. I know how you feel:
<http://www.learnbydestroying.com/jeffl/pics/drivel/#burned-yam.jpg>
That\'s what happened when I cooked a yam (potatoe) for 16 minutes
instead of 6 minutes. It was glowing bright red inside just before I
opened the door. The inside of my Panasonic NN-S533WF (Sensor 1300w)
microwave oven changed from white to yam colored. I tried to clean
it, but the yam color is permanently baked into the paint. The S/N
label says made in 2003. I think I received it as a present in 2005,
making it 15 years old. It works as well today as it did in 2005 with
no change in output level. That\'s one of the benefits of an inverter
oven.

I made sure the magnetron was discharged and between the two connections
I am getting 0 ohms, but I only have a basic multimeter. Between those
and the casing is open.

Try measuring again with a much better ohmmeter or preferably an ESR
meter, which will measure resistances below 1 ohm. The two terminals
on the magottron are the filament wires. Less than 1 ohm is typical
and is easily mistaken for a short circuit.
\"Magnetron Test for Opens, shorts or Insufficient Power\"
<https://www.microwavespecialties.com/pdfs/E10-2010-06%20Mag%20Test%20Bulletin.pdf>
The instructions are for a commerical oven, which may have more than
one magnetron inside, but the methods are the same for a home
microwave oven with only one magnetron.

This microwave is at least 10 years old with a lot of use, so how likely
is it that the transformer has just gone by itself vs the magnetron or
the small mains input board dying and taking the transformer with it?

Near zero. I haven\'t repaired too many microwave ovens and only one
inverter oven. Mostly, what I find are (in order of frequency):
1. Blown high voltage diodes.
2. Blown high voltage capacitor.
3. Blown thermal protection fuse.
4. Filthy and intermittent door interlock switch.
5. Low magentron output or dead magnetron.
I would guess I\'ve fixed about 20 mw ovens and have yet to see a blown
high voltage transformer. If the enamel coating on the torroid are
discoulored from overheating, you might have a problem with the
transformer. If it looks normal, it\'s something else.

You might want to try searching on YouTube for videos on how to
diagnose and repair microwave ovens. This looks like a good start:
<https://www.youtube.com/watch?v=hBJJU4ZRh7U>

The other thing is that the part number of the inverter/transformer
board is A6645M304GP, and the magnetron is a 2M236-M42. A lot of other
models seem to use boards that look identical, but not exactly the same
part number. For example I have found a site saying that this magnetron
can be used with an A66454T05AP or F66454T07AP board, which do look the
same as mine, so are they just a different revision or something or are
the differences going to be bigger?

What you\'re seeing are differences in part number because the
manufacturer sourced their magnetron from multiple (Chinese) sources.
Each source has a different part number, but are functionally and
mechanically identical. The NN-A554W is a 1000 watt oven, so any 1000
watt magnetron that mechanically fits is likely to work.

Even if I need exactly the same board, it looks like I could be chasing
a part that would work in many different models, even different brands,
if only I knew which one to look for (it seems there are no parts for my
model).

No parts? Google is your friend:
<https://www.google.com/search?q=NN-A554W+oven+parts>
Hmmm... are you in the UK? The Panasonic model number seems to be a
UK only 230VAC oven?

Am worried about replacing it and having the new one get instantly blown
up though.

Well, if you want an exact replacement, it would helpful if you would
supply the full model number. Is it NN-A554WB or NN-A554WF ?

If you have no clue what you\'re doing, and are lacking in basic test
equipment, I would recommend:
1. Checking the magnetron with an ohms guesser.
2. If ok, replace the Hi-V diodes and Hi-V capacitor.
3. If that doesn\'t fix it, don\'t replace the magnetron. Instead by a
replacement inverter board. It\'s one of these:
<https://www.kitchenwareonline.com/panasonic-microwave-oven-hv-inverter-m3ffzz000bp-c2x13938345>
<https://www.kitchenwareonline.com/panasonic-hv-inverter-for-microwave-ovens-z606yba00gp-c2x15619538>
4. If that doesn\'t fix it, it MIGHT be the magnetron, but I doublt
it. Magnetrons usually fade away slowly, where cooking takes longer
and longer, until it doesn\'t cook. It does not die suddenly or belch
fire. If you bought a replacement board, you\'ve probably spend more
on the repair than the oven is worth. I suggest you cut your losses
and just buy a new oven.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[pfjw@aol.com]

The longevity of any given appliance is a factor. But, in one\'s choice of appliances, longevity is only one (1) factor. If one looks at the life-cycle cost, the factors are:

a) Cost to produce, market, transport and sell.
b) Cost of energy used over the life of the appliance (and, technically, the source of that energy).
c) Cost of disposal when \'used up\'.

Then, there are wearing parts: hinges & latches, microwave safe internal finishes, bearings and so forth. Investing in repair parts might not give that further ten years.

So, if one assumes that the typical microwave lasts around ten years, and is in actual use for (low end for this purpose) one full hour per week, that comes to 520 hours of operation. A magnetron tube is about 65% efficient these days. Assume all microwaves are a (mere) 700 watts. Assume the US national average cost pr KWH of $0.1331. The equation looks like this:

((700/0.65) x 520)/1,000)=560. 560 x 0.1331 = 74.536. So, it will use $74.54 in electricity in those 10 years at that rate. A modern inverter stands to use, on average, 50% less energy. So use $37 as the \'advantage\' per ten years to the inverter technology.

I dunno... It has been my experience that modern microwaves are largely made of parts made by robots, assembled mostly by robots, tested by robots and (maybe) visually inspected and packed by a exceedingly bored human.

https://www.midea-group.com/About-Us/manufacturing/kitchen-appliances

http://www.midea-gy.com/files/images/shebei/02.jpg

Chances for human error are minuscule. Finishes are far better. Parts variability is far less. And so on. As cheaply made and looking as these things might feel, with proper care and feeding, there is no reason why that $89 dollar device might not last that 10 years and beyond.

Fully agreed on the landfill - we are privileged that most scrap metal from our township is recycled to Acelor Mittal:

https://usa.arcelormittal.com/our-operations/steelmaking/coatesville Which has been in continuous, uninterrupted operation (including wars, depressions, holidays and so forth) since 1810.

It is a process.

Peter Wieck
Melrose Park, PA

 

[pfjw@aol.com]

The longevity of any given appliance is a factor. But, in one\'s choice of appliances, longevity is only one (1) factor. If one looks at the life-cycle cost, the factors are:

a) Cost to produce, market, transport and sell.
b) Cost of energy used over the life of the appliance (and, technically, the source of that energy).
c) Cost of disposal when \'used up\'.

Then, there are wearing parts: hinges & latches, microwave safe internal finishes, bearings and so forth. Investing in repair parts might not give that further ten years.

So, if one assumes that the typical microwave lasts around ten years, and is in actual use for (low end for this purpose) one full hour per week, that comes to 520 hours of operation. A magnetron tube is about 65% efficient these days. Assume all microwaves are a (mere) 700 watts. Assume the US national average cost pr KWH of $0.1331. The equation looks like this:

((700/0.65) x 520)/1,000)=560. 560 x 0.1331 = 74.536. So, it will use $74.54 in electricity in those 10 years at that rate. A modern inverter stands to use, on average, 50% less energy. So use $37 as the \'advantage\' per ten years to the inverter technology.

I dunno... It has been my experience that modern microwaves are largely made of parts made by robots, assembled mostly by robots, tested by robots and (maybe) visually inspected and packed by a exceedingly bored human.

https://www.midea-group.com/About-Us/manufacturing/kitchen-appliances

http://www.midea-gy.com/files/images/shebei/02.jpg

Chances for human error are minuscule. Finishes are far better. Parts variability is far less. And so on. As cheaply made and looking as these things might feel, with proper care and feeding, there is no reason why that $89 dollar device might not last that 10 years and beyond.

Fully agreed on the landfill - we are privileged that most scrap metal from our township is recycled to Acelor Mittal:

https://usa.arcelormittal.com/our-operations/steelmaking/coatesville Which has been in continuous, uninterrupted operation (including wars, depressions, holidays and so forth) since 1810.

It is a process.

Peter Wieck
Melrose Park, PA