Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default Magnetron question

Hi, I have to replace (in a micorwave oven) a Panasonic magnetron 2M236-M62 which is no longer in production and it's difficult to find in my country.
Some spare parts websites list Panasonic 2M236-M42 as an alternative model, but I am unable to find the datasheets to compare values.

Any advice on where to find those datasheets, or a minimum warranty that they are compatible?

Thank you
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See
https://www.directrepair.fr/magnetro...whirlpool.html


technowb a écrit le 12/02/2019 Ã* 22:41Â*:
Hi, I have to replace (in a micorwave oven) a Panasonic magnetron 2M236-M62 which is no longer in production and it's difficult to find in my country.
Some spare parts websites list Panasonic 2M236-M42 as an alternative model, but I am unable to find the datasheets to compare values.

Any advice on where to find those datasheets, or a minimum warranty that they are compatible?

Thank you


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Well, you didn't mention WHAT country so...

I can tell you this. There are only a few types of magnetrons used in uWave ovens. If the mounting fits, 80%+ chance it works. The actual power is determined by the value of the cap and somewhat by the secondary of the transformer.

They can use a higher rated magnetron in a lower powered oven and they still save money by buying more of the same part. They save money on the transformer or the cap.

The mount has to REALLY match. Close is not good enough.
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Semi-related: Will a microwave last longer if lower
power levels are used instead of full power all the
time?

IE: Instead of heating something for the typical one
minute at full power, heating it for two minutes at
half power(or even medium high or 60% if such
setting available)? That way the magnetron cycles
on and off instead of running constantly, and also
the food is more evenly heated.
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On Tuesday, February 12, 2019 at 6:21:46 PM UTC-5, wrote:
Semi-related: Will a microwave last longer if lower
power levels are used instead of full power all the
time?

IE: Instead of heating something for the typical one
minute at full power, heating it for two minutes at
half power(or even medium high or 60% if such
setting available)? That way the magnetron cycles
on and off instead of running constantly, and also
the food is more evenly heated.



In total hours, I get much more time on fluorescent tubes when they're on all the time. I have some that burn all the time for security reasons, and others that get turned off when my shop is closed. I get about the same amount of time before failure out of both.

I suspect magnetrons are the same way. For the less time they're actually accumulating during "low power" settings, they're also getting cycled. My guess is it will ultimately make little difference.



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On Tuesday, 12 February 2019 23:05:14 UTC, wrote:

Well, you didn't mention WHAT country so...

I can tell you this. There are only a few types of magnetrons used in uWave ovens. If the mounting fits, 80%+ chance it works. The actual power is determined by the value of the cap and somewhat by the secondary of the transformer.

They can use a higher rated magnetron in a lower powered oven and they still save money by buying more of the same part. They save money on the transformer or the cap.

The mount has to REALLY match. Close is not good enough.


+1, in principle you can pretty much pick random ones & if they fit perfectly they are likely to work. However I've no idea what the legal requirements are in your unknown country.


NT
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On Tuesday, 12 February 2019 23:57:22 UTC, John-Del wrote:
On Tuesday, February 12, 2019 at 6:21:46 PM UTC-5, wrote:


Semi-related: Will a microwave last longer if lower
power levels are used instead of full power all the
time?

IE: Instead of heating something for the typical one
minute at full power, heating it for two minutes at
half power(or even medium high or 60% if such
setting available)? That way the magnetron cycles
on and off instead of running constantly, and also
the food is more evenly heated.



In total hours, I get much more time on fluorescent tubes when they're on all the time. I have some that burn all the time for security reasons, and others that get turned off when my shop is closed. I get about the same amount of time before failure out of both.

I suspect magnetrons are the same way. For the less time they're actually accumulating during "low power" settings, they're also getting cycled. My guess is it will ultimately make little difference.


Magnetrons generally fail from loss of emission. Fluoro tubes fail from that and from filament breakage, burnout, sputtering & loss of phosphor efficacy. And less common modes like loss of mercury vapour.


NT
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On 2/12/19 11:01 PM, Mike wrote:
Would be interesting to know how the cost of a new magnetron
and the time to replace it compares to the cost of a new
microwave oven.


A new magnetron can vary from $40 (on sale) to $150.

I buy used microwaves at the Good Will and other thrift
stores or garage sales.
I have paid between $10 and $30 for a working one.
I've never bought a new one.

The one I brought with me when I moved was a membrane
control panel and it got stupid. The one upstairs was
the classic "Turn the knob" type, the timer fell apart.

Both were replaced for under $40 total.


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In old µwave, the weak point was the capacitor (High voltage one).
The filament is too much large for dying.though is uses a large current
(some A).
A point to be checked is the cooling fan.

technowb a écrit le 12/02/2019 Ã* 22:41Â*:
Hi, I have to replace (in a micorwave oven) a Panasonic magnetron 2M236-M62 which is no longer in production and it's difficult to find in my country.
Some spare parts websites list Panasonic 2M236-M42 as an alternative model, but I am unable to find the datasheets to compare values.

Any advice on where to find those datasheets, or a minimum warranty that they are compatible?

Thank you




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On Wednesday, 13 February 2019 09:49:55 UTC, Look165 wrote:
technowb a écrit le 12/02/2019 Ã* 22:41Â*:
Hi, I have to replace (in a micorwave oven) a Panasonic magnetron 2M236-M62 which is no longer in production and it's difficult to find in my country.
Some spare parts websites list Panasonic 2M236-M42 as an alternative model, but I am unable to find the datasheets to compare values.

Any advice on where to find those datasheets, or a minimum warranty that they are compatible?

Thank you


In old µwave, the weak point was the capacitor (High voltage one).
The filament is too much large for dying.though is uses a large current
(some A).


around 13A, so far more robust than a fluoro tube.


NT
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I totally agree.
Sometimes, it is cost effective to change the oven instead of fixing it.
Fixing it needs to get a new magnetron with the exact footprint if not
it will not be OK.

The only to check is the filament ; if it is OK, the problem is
somewhere else (I think the HV capacitor or the diode).
It can happen that the mains transformer is out, but rare.

Ralph Mowery a écrit le 13/02/2019 Ã* 15:53Â*:
In article , says...
Would be interesting to know how the cost of a new magnetron
and the time to replace it compares to the cost of a new
microwave oven.

It goes without assuming that you're sure the magnetron is at fault?


Could be different in other countries, but at the cost of the microwave
ovens in the US, the cost of a new megatron tube and shipping is
probably as much if not more than a replacement oven.

A long time ago I decided that it is just not worth it to do most
repairs (if you have to buy parts) on items costing under $ 500. If you
have to get someone else to repair an item, just replace it.


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Thank you guys, in this case it should be worth to repair it since the oven is 5 years old and in pretty good conditions: the only issue is with microwaves features, but it still works as an oven with grill.Â*

It's a built-in big "luxury" model that still costs around 700‚¬ new: it broke too early in my opinion because it was always been used following the rules (I am sure of that, It's my oven.. )

The official tech support said that I would need to buy a new one because they can't find the magnetron, but I cannot afford another expense of that kindÂ* - in particular for a product that can't be repaired after too little time..


I think that unless I find the same exact magnetron I will go for the suggested alternative, at least It's worth a try.Â*

Do you know what would happen if the alternative is a wrong option?Â*

Would I risk frying inverter module or something else?Â*

Given the price of the spare parts I could also think of selling those to buy a new one "with some discount".


Thank you again

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On 2/13/19 10:36 AM, technowb wrote:
Do you know what would happen if the alternative is a wrong option?

Would I risk frying inverter module or something else?


The primary issue would be how the microwaves get from the magnetron
to the oven chamber. That's THE critical item. Physical match.

A more obscure and unlikely problem would be the heater voltage to
run the tube with.

Then there's the little details. Does the HV supply exceed the tube
ratings.
Does the tube draw more current than than the HV supply can supply?



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http:foxsmercantile.com


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Much as I am not happy with needless landfill, nor with the tissue-paper economy that builds irreparable crap these days, there comes a time when it is best to simply dump the item rather than attempt to salvage it.

Microwaves are one of those things. Given the very real safety issues raised by after-sales work on these devices, there is no particular reason to make such repairs unless the unit is otherwise special (perhaps a vintage Amana or similar, or an early built-in) or hideously expensive to replace.

And, as Jeff suggests, a visit to any thrift-store will yield any number of options.

That being written, our incumbent microwave is 10 years old, the one on our third floor followed us back from Saudi in 2005, and the one at our summer house is now seven (but gets little use).

Peter Wieck
Melrose Park, PA
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Mr. Wieck don't you think this one falls into "hideously expensive to replace"?
Given that a luxury microwave oven costs around 300‚¬ and this one costs more than 700, I'd say it does.. there are almost no more expensive combi ovens in the market: other cheaper ovens I owned lasted 15 years and such.

I would be happy to buy another one and avoid complications, but I cannot afford it, and I am trying to understand the implications of the choice to self-repair it.
I know that there may be serious injuries ahead, that's why I am gathering informations here and there before taking any further step..
Thank you
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On Wednesday, February 13, 2019 at 1:43:38 PM UTC-5, technowb wrote:
Mr. Wieck don't you think this one falls into "hideously expensive to replace"?
Given that a luxury microwave oven costs around 300‚¬ and this one costs more than 700, I'd say it does.. there are almost no more expensive combi ovens in the market: other cheaper ovens I owned lasted 15 years and such.

I would be happy to buy another one and avoid complications, but I cannot afford it, and I am trying to understand the implications of the choice to self-repair it.
I know that there may be serious injuries ahead, that's why I am gathering informations here and there before taking any further step..
Thank you


Apparently (or should I say supposedly), this magnetron replaces the one in your unit:

https://www.directrepair.eu/microwav...panasonic.html

About 100E with freight. Are you sure the magnetron is bad? A lot of things can prevent it from being powered up: door interlock switch, control board problem, burned relay (or connection - not uncommon on Whirlpools), HV diode or HV capacitor.

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On Wednesday, February 13, 2019 at 1:43:38 PM UTC-5, technowb wrote:
Mr. Wieck don't you think this one falls into "hideously expensive to replace"?


OK - not knowing where you are, other than somewhere in Europe:

https://www.europart.nl/whirlpool-ma...etron-92716700

Not so expensive, either.

This part was used in a number of brands, from Jenn-Aire to Panasonic to Whirlpool, and others. So, attach the PN to other brands, it may pop up.

Peter Wieck
Melrose Park, PA


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On 2/13/2019 10:43 AM, technowb wrote:
Mr. Wieck don't you think this one falls into "hideously expensive to replace"?
Given that a luxury microwave oven costs around 300‚¬ and this one costs more than 700, I'd say it does.. there are almost no more expensive combi ovens in the market: other cheaper ovens I owned lasted 15 years and such.

I would be happy to buy another one and avoid complications, but I cannot afford it, and I am trying to understand the implications of the choice to self-repair it.
I know that there may be serious injuries ahead, that's why I am gathering informations here and there before taking any further step..
Thank you

I haven't heard a convincing argument that the magnetron is the problem.
How did you verify that?
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@Mike I have no hard evidence about the magnetron being faulty, however this was the diagnosis made by the tech guy who came over to fix it.
The whirlpool oven displays error F05 (which I was not able to find anywhere in my research over the internet). It displays it only when using features that relay on microwawes, other than that it works fine.
The "official repair guide" - which I have not seen - seems to state that to fix error F05 it is needed to replace the inverter board and the magnetron.
Since the tech guy had a spare new inverter board, he switched it and left it in the oven, unfortunately that didn't fix the error. That's the reason why I am assuming it's the faulty magnetron.. I am actually hoping that, trusting that the tech guy placed a working inverter board inside my oven.

Thank you for your inputs, you're being really helpful


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On 13-2-2019 20:02, John-Del wrote:
On Wednesday, February 13, 2019 at 1:43:38 PM UTC-5, technowb wrote:
Mr. Wieck don't you think this one falls into "hideously expensive to replace"?
Given that a luxury microwave oven costs around 300€ and this one costs more than 700, I'd say it does.. there are almost no more expensive combi ovens in the market: other cheaper ovens I owned lasted 15 years and such.

I would be happy to buy another one and avoid complications, but I cannot afford it, and I am trying to understand the implications of the choice to self-repair it.
I know that there may be serious injuries ahead, that's why I am gathering informations here and there before taking any further step..
Thank you


Apparently (or should I say supposedly), this magnetron replaces the one in your unit:

https://www.directrepair.eu/microwav...panasonic.html

About 100E with freight. Are you sure the magnetron is bad? A lot of things can prevent it from being powered up: door interlock switch, control board problem, burned relay (or connection - not uncommon on Whirlpools), HV diode or HV capacitor.

Shop for a second hand one of the same age/power range, and swap components.
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"IE: Instead of heating something for the typical one
minute at full power, heating it for two minutes at
half power(or even medium high or 60% if such
setting available)? That way the magnetron cycles
on and off instead of running constantly, and also
the food is more evenly heated. "

No. It is doing the same work AND being thermally cycled. Now had you an older one where they put more than six bucks into it, they had a lower tap on the transformer for the lower power setting. One of those maybe. With that, lower power might just make the tube last longer. Not by cycling on and off for a longer time.
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"I suspect magnetrons are the same way. "

It seems CRTs are. I had a Zenith 20" come in, had the best picture I ever saw on that model because the tube was strong. I mean STRONG. Te complaint was there was a slight noise when it was turned off. I discovered that it really wasn't turning off, when the micro said power off it muted the audio and video but the HV, and of course the filament of the CRT and all that was still on. I told them not to fix it. Management didn't agree so it got fixed.

We knew for a long time about CRTs, like NEC bigscreens had active all the time AKB and when you first turned them on they were actually "cathode stripping". Sony's AKB had a delay until beam current was normalized, as told by the AKB circuit. Didn't help, their CRTs were junk by then. But I got this 35 year old Sony in my room with about the best god damn picture you ever saw, and it is never shut off. To shut it up I just switch to a dead source. You will NOT see color like on this thing.

Anyway, the magnetron has a filament so when it cycles on and off the filament thermally cycles and in almost ANYTHING in the physical world thermal cycling is bad.

The old microwaves with the tap, the filament voltage was still the same.

Actually if you look at the power level switch on one of them you can see it is made to switch a few thousand volts. It is not a simple slide switch.
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For my GE micro, power level cycling is as follows:

HI/Full - Magnetron on continuously
90% - On 27sec, off 3sec
80% - On 24sec, off 6sec. etc etc.
50%/Medium - On 15sec, off 15sec
20%/Lowish - On 6sec, off 24sec

And so on.

I'm sure the designers took everything into
account when providing for all those power
levels. I almost never use Full, except for
when boiling water.


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On 2/13/2019 2:20 PM, wrote:
On Wed, 13 Feb 2019 13:43:17 -0800 (PST),
wrote:

On Wednesday, 13 February 2019 20:07:20 UTC, wrote:
On Tue, 12 Feb 2019 15:05:11 -0800 (PST),
wrote:

Well, you didn't mention WHAT country so...

I can tell you this. There are only a few types of magnetrons used in uWave ovens. If the mounting fits, 80%+ chance it works. The actual power is determined by the value of the cap and somewhat by the secondary of the transformer.

They can use a higher rated magnetron in a lower powered oven and they still save money by buying more of the same part. They save money on the transformer or the cap.

The mount has to REALLY match. Close is not good enough.
So the reason microwave ovens cycle on and off at the lower power
settings is because different caps would be needed for different power
outputs? I always thought it was the tube itself, that it worked best
at some certain power output.
Eric


Early 2 power level nukes used a capacitor & HV switch to reduce anode i. It's cheaper & more reliable to switch the power on & off. And safer. The only time it matters is with mousse.


Try cooking an egg to dispel that thought.
Older microwaves had minimum on-time because of the filament warm up
time...and the lack of high voltage power supply electronics back then.
A 10-second on-time is plenty of time for localized heating to cause
food to explode.
The newer inverter microwaves have much shorter on-times so food doesn't
explode as easily even at the same average power.


NT

Darn it! I was gonna try to make some mousse tonight in the microwave.
Eric


Under what conditions did the microwave fail?

Did it quit while in use? Between uses?
Any power outages or lightning storms in between?

I've never fixed a newer microwave. All my repairs were diode
replacements in older machines. I don't think I'd even try
to fix my Panasonic inverter without a full set of schematics.
Even then, all the sensors would be a nightmare to reverse-engineer.

I'm gonna make some guesses.
I doubt that the magnetron has failed.
Sure, it can crack if you overheatd it by running it
for long periods nearly empty.

More likely something else failed.
There's not much to cause instant failure of a magnetron
if you didn't overheat it.
I doubt that there are any high voltage components on
the controller that was replaced.
The oven is full of sensors for safety and cook control.
Any of them can cause the system to inhibit the microwave function.
I'd guess that the only things a controller would monitor
might be power supply voltage and temperature.
Just not worth the expense to do more. But there's plenty
more to go wrong.

Here's some reading material.

https://www.thermex-thermatron.com/w...netrons_v3.pdf

https://www.repairfaq.org/sam/micfaq.htm

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Thank you! I've read everything, and I searched for the exact magnetron; unfortunately I have to go for an "80% compatibile model" since everytime I find a website listing the correct model it's either out of stock or the website fails under a 404 error.

I have one more question, since I noticed a difference between apparently the same model by different manufacturers:

Does the shape of the hole of the "microwaves cannon" make some difference? I can't find one with the exact shape of my original model (square): the available shapes of the alternatives are circle and triangle.. should I go for one of those randomly or there are better chances of compatibility if I choose one over the other?

Thank you again
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Try
https://www.cdiscount.com/electromen...m42.html#_his_

technowb a écrit le 12/02/2019 Ã* 22:41Â*:
Hi, I have to replace (in a micorwave oven) a Panasonic magnetron 2M236-M62 which is no longer in production and it's difficult to find in my country.
Some spare parts websites list Panasonic 2M236-M42 as an alternative model, but I am unable to find the datasheets to compare values.

Any advice on where to find those datasheets, or a minimum warranty that they are compatible?

Thank you


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"Which of course, is entirely relevant to magnetrons. "

I dunno bout that. A magnetron has a cathode heating up with full plate voltage applied which is known to cause damage to CRT cathodes. That's why Sonys with AKB had a turn on delay until the detected tickle current is up to a certain level. It lessens "cathode stripping". Well lessenED, no more CRTs, more useless knowledge.

Think you bad to the bone ? Got moxy, resources n **** ? Wana make some money ?

Build a left handed microwave. Seriously, there is a market and some people really need them and NOBODY makes them. They all go the same way but not everybody's kitchen goes the same way. Just look at your microwave in a mirror and that is what could sell. You would have 100% of the market for maybe a couple of years.

Get your torches, MIG welders, die grinders, the usual implements of destruction and get rich.

I actually looked into it, it is a big pain in the ass. And you only get a couple years because the big boys will start making them as soon as they detect your presence in the market.

Now THAT's irrelevant...but true.


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Lefthanded microwaves:

I think I've seen a few lefthanded TV sets(CRT era)!

Where the tuning knob, volume, brighness, speaker
are to the left of the picture tube.
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Hi guys, thank you all.
I can confirm that in AMW842IX - that uses magnetron 2M236-M62 by default - we can use as an alternative magnetron 2M236-M42 by Panasonic. I am not sure if other brands of the same model works the same, however the oven is on duty again, and trying to repair it was worth the effort.

Thank you again
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