microwave magnetron dead?

[mynick]

no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?

 

[mm]

On Thu, 15 Oct 2009 09:02:27 -0700 (PDT), mynick <anglomont@yahoo.com>
wrote:

no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?

This is tube that came with a microwave oven, and the tranformer that
came with it too?

Did it used to work?

I think it unlikely that it requires a mere 1 volt more voltage, or
that the working transformer doesn't provide the right voltage. The
transformer may be the most expensive part ot replace.

Be careful running the thing with the cover off. I presume there is
still a shield around the microwave tube, but if so, absolutely don't
run the thing without the shield. Radio Shack used to sell
inexpensive (10$) microwave detectors, for testing leakage around
microwave ovens. Maybe they still sell them. I know that mine
worked well, because I had an overn without a latch, and by pulling
the door open a little, I was able to watch the meter reading rise
from very very low to quite a bit higher.

 

[Zootal]

"mynick" <anglomont@yahoo.com> wrote in message
news:2112a54d-187c-4cbc-8652-12c2d506132b@p4g2000yqm.googlegroups.com...

no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?

Do you have experience with high voltage and RF equipment, especially
microwave/radar frequencies? Do you have the equipment for measuring high
voltage safely? You need something that can handle 10,000 volts - a cheap
Radio Shack meter will not do this safely. By the questions you ask, I'm
guessing you don't.

I very strongly recommend that you close up the cabinet and either take it
to someone that knows what they are doing, or throw it in the trash.
Microwave ovens are incredibly dangerous if you don't know what you are
doing, and you can end up seriously injured or dead real fast. It's not
worth it - just throw it in the trash.

If you really want to try to fix it and risk killing yourself and burning
down your house, etc.

Try here; http://www.gallawa.com/microtech/

It has some basic service procedures, but I don't think you will find
anything telling you how to troubleshoot the RF or high voltage circuitry.
That requires special knowledge and equipment that not even a lot of the
techs that fix these things have.

 

[HeyBub]

abo mahab wrote:

Belief in God by Shaikh Shahidullah Faridi


It is mistakenly imagined by some that belief in a Supreme Being as
the Creator and Controller of the universe is a mere emotional
aspiration, a superstition of ancient times, irrational and illogical,
and exploded by modern science....

I see you're posting from 93.98.28.228, which works out to be

IP address: 93.98.28.228
Reverse DNS: [No reverse DNS entry per ns-pri.ripe.net.]
Reverse DNS authenticity: [Unknown]
ASN: 34397
ASN Name: CYBERIA-RUH (Cyberia Riyadh Autonomous
System)
IP range connectivity: 2
Registrar (per ASN): RIPE
Country (per IP registrar): SA [Saudi Arabia]
Country Currency: SAR [Saudi Arabia Riyals]
Country IP Range: 93.98.0.0 to 93.98.255.255
Country fraud profile: Normal
City (per outside source): Riyadh, Ar Riyad
Country (per outside source): SA [Saudi Arabia]
Private (internal) IP? No
IP address registrar: whois.arin.net

Whatsa matter? Couldn't find anyone in your country interested in listening
to you?

 

[GregS]

In article <c9d6d85c-9c18-4883-92b2-32ba8945e6da@b2g2000yqi.googlegroups.com>, JIMMIE <JIMMIEDEE123@YAHOO.COM> wrote:

On Oct 15, 12:02=A0pm, mynick <anglom...@yahoo.com> wrote:
no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?

Could be a lot of things most are unsafe to test without proper
equipment and experience. The voltages exceed that which can be safely
handled by most voltmeters. Back when I used to work on these things
the first things I would check is the diode, filament caps, power
supply cap. I could do this safely with ohm meter and Hi-pot tester.
I had a homebrew test bed for checking transformers, don't even think
of measuring voltage on these even the filament are at multi kilovolt
levels and grounded to the chassis. The decision to replace the maggie
was usually based on a process of elimination.

I ran into that recently. It sort of started to work by generating heat,
but that didn't last long. I like using an old analog meter with the 5 KV scales.
I didn't get a chance to replace the manetron. It cost the owner a bunch for the transformer
and diode.

The diode and transformer became BAD, but don't know at what point.
Before or after the manetron went bad.

greg

 

[jamesgangnc]

On Oct 15, 12:02 pm, mynick <anglom...@yahoo.com> wrote:

no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?

Loud hum sometimes means something is shorted. The increased load on
the transformer makes it hum more. You can't always detect a short in
a high voltage component with an ohm meter. You can measure the
heating element voltage with an multi-meter but you really ned to be
careful. There is probably a diode and capacitor in the high voltage
circuit as well. If the diode has shorted the ac load will go through
the capacitor and that can also cause the high hum. I tried to fix
one once that had a bad magnitron but the magnitron was about half the
cost of a whole new microwave,

 

[JIMMIE]

On Oct 15, 12:02 pm, mynick <anglom...@yahoo.com> wrote:

no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?

Could be a lot of things most are unsafe to test without proper
equipment and experience. The voltages exceed that which can be safely
handled by most voltmeters. Back when I used to work on these things
the first things I would check is the diode, filament caps, power
supply cap. I could do this safely with ohm meter and Hi-pot tester.
I had a homebrew test bed for checking transformers, don't even think
of measuring voltage on these even the filament are at multi kilovolt
levels and grounded to the chassis. The decision to replace the maggie
was usually based on a process of elimination.

Jimmie

 

[abo mahab]

Belief in God by Shaikh Shahidullah Faridi


It is mistakenly imagined by some that belief in a Supreme Being as
the Creator and Controller of the universe is a mere emotional
aspiration, a superstition of ancient times, irrational and illogical,
and exploded by modern science. It is believed that scientists
(physicists, biologists and others) have erected some theory which
both refutes and replaces the traditional belief in God. Such ideas
have only a very superficial grounding, and are the result of
ignorance or an indifference to both the fundamentals of religious
faith and the scope of the physical sciences. It is a significant fact
in the history of world thought that very few people have ever made it
their business to refute the existence of God. The views of the
universe which are considered to be anti-religious are almost all
agnostic, not atheistic, that is to say, they attempt to ignore the
existence of God instead of denying it. This is true of certain views
of modern science as well as of the ancient non-religious theories.
The universe in which we live comprises an evident system of causes
and effects, of phenomena and their results, and it is possible to
discuss them indefinitely and construct theories about them, giving a
superficial appearance of completeness. This is done, however, only at
the expense of ignoring fundamentals or claiming that they cannot be
known. If one were to search for a convincing statement based on firm
principles that the existence of a Supreme Being is impossible, one
would not be able to find it.
The reason for this state of affairs is that belief in God is at once
instinctive, rational, evidential and intuitional, and it is only by
deliberately neglecting to consider it that the non-religious attitude
is maintained. It is instinctive in that man has an innate feeling of
his own inadequacy and helplessness, which accompanies him from the
cradle to the grave, a feeling accompanied by the complementary desire
to seek refuge and support with a being who controls all those forces
before which he feels himself inadequate. We put this feeling forward
as instinctive, although it will immediately be perceived that it is
also evidential. The weakness of man before all the uncountable
influences over which he has no control is a fact so obvious as to
require no discussion.

What is less well grasped by some who have claims to intelligence is
that belief in God is fully supported by reason and logic, the
principles on which all human intelligence stands. For instance, it is
a basic requirement of reason that an effect cannot exist without a
cause. However hard we press our mental faculties, we cannot conceive
rationally of a causeless effect, and if we wish to postulate one we
can only do so by temporarily putting our reason on the shelf. Reason
leads us to the conclusion that just as the elements which compose the
universe are effects of certain causes, the universe itself must be
the effect of a cause, a cause which is itself mightier than and
outside the universe. Non-religious thinkers have to ignore the origin
of the universe and postulate something existing in the beginning
without any known cause. This postulate is essentially non-rational
and therefore unscientific, but it is a necessity for those thinkers
who have unconsciously or deliberately decided not to consider
fundamentals. Of these there are even some who openly proclaim their
refusal to discuss or admit any metaphysical concept. This kind of
attitude, however, can only be upheld by abandoning reason. Reason
itself guides us inexorably to the conclusion that there is an
ultimate cause, the Cause of causes, beyond this universe of time,
space and change; in fact, a Supreme Being.

Another of the basic demands of reason is that diversity cannot exist
without a fundamental unity. Whenever the human mind is confronted
with diversity, it immediately sets to work to synthesise it into
unities, then to synthesise these unities into higher unities and so
on until it can go no further. The ultimate result of a rational
consideration of diversity is to arrive at a unity of unities, a
Supreme Unity, the producer of all diversities, but itself essentially
One. Whichever fundamental of reason we select, if we follow its path
we are led inevitably to the same goal - belief in God, the Supreme
Being.

Besides the conclusion arrived at by purely rational processes, man is
led to the belief in God by observation and experience. One of the
principal reasons for man’s refusal to recognize the existence of God
is the intellectual arrogance produced by his appreciation of his own
powers of analysis and synthesis, of harnessing physical forces by his
ingenuity, and of constructing complex machines to do his work for
him. But pride is caused by concentrating too much attention on one’s
own virtues and blinding oneself to one’s defects. What are the best
of man’s mechanical inventions but a poor and crude imitation of what
already exists in an infinitely finer form in nature? By copying in an
elementary fashion some of the functions of the human eye, he has been
able to evolve the camera; but what comparison has this machine, made
out of lifeless materials, to the living stuff of the eye, and to the
refinement, brightness, clarity, flexibility and stability of its
vision, its immediate connection with the mind which sifts and
appreciates all it sees, all without a complicated system and
controls, and directly under the command of the human will? Take any
organ of the body and study it - the heart, the brain - and it will
immediately be obvious that it is quite outside the scope of man’s
ability to conceive and fashion such an instrument. The petty
imitations of man are attributed to his great cunning, artistry and
intelligence. Is it then reasonable, logical or scientific to
attribute the infinitely finer and more perfect instruments of nature
to such vague and blind energies called by names such as the ‘life
force’, or ‘matter in evolution’, and leave them undescribed and
unexplained? If logic has any validity (and if it has not we had
better stop thinking altogether and become animals), the intelligence
which conceived and wrought myriads of such delicate and astonishing
devices must be infinitely superior to the human intelligence (even
the human intelligence is one of its products), and have control of
all the materials and workings of the universe. Such an intelligence
can only be possessed by a Supreme Being, the Creator, Fashioner and
Sustainer of all things.

If we ponder our own place in the world, we find that we (as well as
all other beings) are kept in being by a most intimate combination of
forces and conditions, which is so delicate that even a small
dislocation would cause our total destruction. We live, so to speak,
continually on the brink of annihilation, and yet are enabled to carry
on our complex existences in comparative immunity. We cannot live, for
instance, without daily rest; both the human body and the human mind
are constructed to need it. This fact is not in itself surprising, but
what is surprising is that the solar system collaborates with us in
our human frailty and provides us with a day and a night exactly
suited to our needs. Man cannot claim to have compelled or persuaded
the solar system to do so; nor can the solar system claim to have
modelled human physical and mental energy to conform to its own
movements. Both man and the solar system are evidently linked in a
total organisation in which man is the beneficiary; the organiser of
these inexplicable concordances can only be a Supreme Controller of
the universe and mankind. Sweet water is a necessary condition of
human existence; it is equally necessary for those plants which
produce man’s staple foods, which themselves depend on each other. If
sea water were to invade our rivers and wells or rain down from the
sky, is there any doubt that we should all die of hunger and thirst in
a few days and the whole world become an empty desert? Yet sea water
is only held back by an invisible barrier over which we have no
control, and the sun and the clouds co-operate in order to desalinate
our water for us and so give us life. This linkage of interdependence
and concurrence could be extended indefinitely by taking examples from
the physical world, and to describe it as ‘fortuitous’ is only begging
the question; moreover it is a contradiction in terms. Fortuity is the
name for something which does not come within any known system or
regulation, an apparently meaningless and haphazard occurrence. To
call a system which is a balanced and cohesive organization fortuitous
is obviously self-contradictory and fallacious. A ‘fortuitous system’
is, simply, an absurdity. If we observe carefully we can see that the
whole of the universe is interdependent and interlinked and therefore
not fortuitous but planned. Belief in God means, precisely, belief in
a Planner of the universe.

A basic element in human consciousness - a suprarational element - is
a sense of value and purpose in respect to life. Even the worst of men
is prevented from becoming completely bestial by this feeling, and in
the best of them it dominates their whole existence. The senses of
good and evil, right and wrong, beauty and ugliness, fitness and
unfitness, truth and falsehood are such that however attacked by the
missiles of constructive analysis, they remain intact within their
intuitional fortress. In all ages and conditions, man has not been
able to divest himself of the idea that behind its external effect,
every action possesses a quality by which it may be judged and graded
in the scale of final values. In addition to the consciousness of the
existence of these values, there is the feeling that it is the purpose
of man’s life to attain those qualities which reflect the highest of
them, that not only are they excellent in themselves and worthy of
being acquired, but that they must be acquired, and that he has been
created to acquire them. The natural sense of qualitative purpose, if
allowed to develop freely without the cramps of agnostic prejudice,
leads him to the conception of an absolute good and an absolute truth
as the ultimate standard of human existence, and from there (for a
quality cannot exist except in a being who is qualified by it) to a
being who is the possessor and author of these qualities, the Supreme
Purposer.

The decisive vindication of the existence of God is evidential. At
various junctures in world history and in widely distant places,
certain men have arisen and proclaimed that they have been inspired by
God to give His message to mankind. These men were not mad; we have
historical records of several of them, including all or part of the
message they insisted that they were called to deliver, and it is
obvious that they were men who were intellectually and morally highly
impressive. They did not come all at once so that we could attribute
them to a sort of historical fashion. They came spaced throughout
history usually at a time of great moral degeneration. If we examine
their message, we find that apart from differences of expression,
attributable to the milieu in which they lived, they not only bear
remarkable similarities but are basically identical. They have stated
that God had conversed with them in some inspirational manner, and had
ordered them to proclaim His Existence as the Creator, Maintainer,
Controller and eventual Destroyer of the world, to describe His Mercy
and Justice, and to warn mankind that it is only by remembering and
worshipping Him and following the moral and practical principles that
He has laid down for them that they can achieve success and happiness
here and hereafter.

The last of these prophets was Muhammad of Mecca, who stated that
there would be no prophet after him, and it is a demonstrable
historical fact that no-one has been able to establish a claim to
prophethood since. Now those who discuss or refuse to discuss the
existence of God almost invariably rely on rational or anti-rational
arguments and rarely, if ever, consider the evidential factor. The two
basic elements in human knowledge are, firstly, our own observations
and conclusions, and secondly, the evidence of others. Among the
branches of knowledge the whole of history, for example, and most of
the average man’s acquaintance with science, are only known from the
evidence of others, unless he himself is a specialist in the subject.
When specialists in a certain branch of knowledge continuously assert
that a certain thing is a fact, it becomes a necessity for the rest of
mankind, who are unable to acquire this knowledge directly, to accept
it as such. In the field of direct inspiration from God, and knowledge
of His qualities and works, we have the repeated evidence of people in
history who have affirmed their apprehension of Him and that they have
been charged with conveying His message; not only that, the realities
of the divine and spiritual realism as described by these prophets
have in various degrees been corroborated and confirmed by the
spiritual experiences of an uncounted number of their followers right
up to the present day. These corroborators have been the saints and
mystics of their various communities. This continuous and widespread
evidence of the existence of God, the central and original evidence of
prophets, and the derivative and confirmatory evidence of their
followers, all based on modes of direct and intuitional perception of
His Being, cannot with any reasonability be denied or ignored. To deny
or ignore them is patently illogical and unscientific, and against the
basic principles of the acquirement and dissemination of human
knowledge. In addition to being instinctive, intuitional, and logical,
belief in God has irrefutable evidence to prove its verity.

The writer (1915-1978) was an English convert to Islam who became a
Shaykh of the Tariqa Chishtiyya, living a life of simplicity in
Karachi, Pakistan, where his holiness gained him the love and devotion
of thousands of Muslims from all walks of life. May Allah show him His
mercy, and grant him light in his grave. Amin.



by Shaikh Shahidullah Faridi

 

[jeff_wisnia]

mynick wrote:

no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?

Watch out for a big capacitor in there which in some cases can give you
a nasty high voltage bite even after the oven has been unplugged for a
while.

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10e12 furlongs per fortnight.

 

[Tony Hwang]

mynick wrote:

no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?
Hi,

More than magnetron. Suspect your HV source.

 

[Jamie]

mynick wrote:

no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?
Sounds like it maybe the HV-Diode..

P.S.
You most likely won't be able to test it with your
DMM unless it's totally shorted.

 

[Erik]

In article
<V_mdnRi47aTGP0rXnZ2dnUVZ_sqdnZ2d@posted.choiceonecommunications>,
jeff_wisnia <jwisnia@dumpthisconversent.net> wrote:

mynick wrote:

no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?


Watch out for a big capacitor in there which in some cases can give you
a nasty high voltage bite even after the oven has been unplugged for a
while.

Jeff

Or as a guy I know would so eloquently warn... "Dont ya'll be messin
with that s**t lest you know what you doin; it'll up'n give yo ass a
dirt nap"

Good advise too. I hate 'dirt naps' anymore, especially now that I'm a
bit older.

Microwaves reached disposable appliance status eons ago... if it's not
in warranty, spring for a new one, they're cheap.

Erik

 

[GregS]

In article <V_mdnRi47aTGP0rXnZ2dnUVZ_sqdnZ2d@posted.choiceonecommunications>, jeff_wisnia <jwisnia@dumpthisconversent.net> wrote:

mynick wrote:

no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?


Watch out for a big capacitor in there which in some cases can give you
a nasty high voltage bite even after the oven has been unplugged for a
while.

I was checking out an amplifier I built and broke, and sitting for a couple years.
Sure enough, I got a spark messing around with it.

greg

 

[mynick]

On Oct 16, 4:01 am, Erik <s...@this.com> wrote:

In article
V_mdnRi47aTGP0rXnZ2dnUVZ_sqdn...@posted.choiceonecommunications>,

jeff_wisnia <jwis...@dumpthisconversent.net> wrote:
mynick wrote:

no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?

Watch out for a big capacitor in there which in some cases can give you
a nasty high voltage bite even after the oven has been unplugged for a
while.

Jeff

Or as a guy I know would so eloquently warn... "Dont ya'll be messin
with that s**t lest you know what you doin; it'll up'n give yo ass a
dirt nap"

Good advise too. I hate 'dirt naps' anymore, especially now that I'm a
bit older.

Microwaves reached disposable appliance status eons ago... if it's not
in warranty, spring for a new one, they're cheap.

Erik

I meant what is going to happen if you try replace original magnetron
with one that has 4.13v or 3.6v filament voltage but original hv
transformer gives 3.15V

 

[JIMMIE]

On Oct 16, 8:07 am, mynick <anglom...@yahoo.com> wrote:

On Oct 16, 4:01 am, Erik <s...@this.com> wrote:



In article
V_mdnRi47aTGP0rXnZ2dnUVZ_sqdn...@posted.choiceonecommunications>,

 jeff_wisnia <jwis...@dumpthisconversent.net> wrote:
mynick wrote:

no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?

Watch out for a big capacitor in there which in some cases can give you
a nasty high voltage bite even after the oven has been unplugged for a
while.

Jeff

Or as a guy I know would so eloquently warn... "Dont ya'll be messin
with that s**t lest you know what you doin; it'll up'n give yo ass a
dirt nap"

Good advise too. I hate 'dirt naps' anymore, especially now that I'm a
bit older.

Microwaves reached disposable appliance status eons ago... if it's not
in warranty, spring for a new one, they're cheap.

Erik

I meant what is going to happen if you try replace original magnetron
with one that has 4.13v or 3.6v filament voltage but original hv
transformer gives 3.15V

Video Please, I want to see this on stupid microwave tricks.

Jimmie

 

[terry]

On Oct 16, 10:07 am, mynick <anglom...@yahoo.com> wrote:

On Oct 16, 4:01 am, Erik <s...@this.com> wrote:





In article
V_mdnRi47aTGP0rXnZ2dnUVZ_sqdn...@posted.choiceonecommunications>,

 jeff_wisnia <jwis...@dumpthisconversent.net> wrote:
mynick wrote:

no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?

Watch out for a big capacitor in there which in some cases can give you
a nasty high voltage bite even after the oven has been unplugged for a
while.

Jeff

Or as a guy I know would so eloquently warn... "Dont ya'll be messin
with that s**t lest you know what you doin; it'll up'n give yo ass a
dirt nap"

Good advise too. I hate 'dirt naps' anymore, especially now that I'm a
bit older.

Microwaves reached disposable appliance status eons ago... if it's not
in warranty, spring for a new one, they're cheap.

Erik

I meant what is going to happen if you try replace original magnetron
with one that has 4.13v or 3.6v filament voltage but original hv
transformer gives 3.15V- Hide quoted text -

- Show quoted text -

Those numbers don't seem to make any sense at all. Sounds like maybe
something is shorted or the capacitor or rectifier is shot.

BE VERY, VERY CAREFUL. LETHAL VOLTAGES!!!!!!!.

My advice is always, don't mess with it unless you are a competent
high voltage/radio transmitter technician!
There are voltages of 5000+ volts and potential RF radiation that can
fry your eyes (cos that's what it does in minutes to meat, eh?). In
effect a m.wave oven is a one kilowatt radio transmitter in a tin box!
And much less than that can easily kill you!!!!!!!!

The circuit is complex enough that the typical do it yourself-er may
not be able to follow. For example we recently fixed, in less than 20
minutes, a microwave that the owner, a capable sort of chap for most
'carpentry type' repairs, but not an electronics technician, thought
had a bad component in the power supply (HV transformer, rectifier,
capacitor etc.) .

Then he thought it was something to do with the control panel!

Initially I had thought it might be the contacts of the relay on the
control panel that switches most of the power the m.wave uses. One
could hear it closing but no power!

It wasn't any of those! The problem was a defective door micro-switch
(Canadian Spec. not necessarily same as USA by the way!) that
prevented basic 115 volts AC from reaching the fan, the power supply,
the interior light etc. etc. A somewhat basic fault as it turned out.
We had a spare micro-switch of the same spec. from a junked m.wave
fairly easy install, stand back, since the cover was still off, for a
test and it was all done.

Not only the wrong diagnosis, twice, plus my first thought about the
control realy; but the owner had put the cover back on incorrectly and
it had a slight gap where microwaves 'might' be able to leak right
near the door 'handle'! Not good.

For goodness sake 'BE CAREFUL' a replacement m.wave can be had for
around $50 and the risk is not worth it.

 

[mynick]

On Oct 16, 6:14 am, zekfr...@zekfrivolous.com (GregS) wrote:

In article <V_mdnRi47aTGP0rXnZ2dnUVZ_sqdn...@posted.choiceonecommunications>, jeff_wisnia <jwis...@dumpthisconversent.net> wrote:

mynick wrote:

no shorts betweenmagnetroncontacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is itdead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?

Watch out for a big capacitor in there which in some cases can give you
a nasty high voltage bite even after the oven has been unplugged for a
while.

I was checking out an amplifier I built and broke, and sitting for a couple years.
Sure enough, I got a spark messing around with it.

greg

If the filament voltage->current is too low maybe it will not
emmit,why else is that magnetron spec?

 

[lawei]

responding to
http://www.homeownershub.com/maintenance/microwave-magnetron-dead-400476-.htm
lawei wrote:

mynick wrote:

no shorts between magnetron contacts or ground but when plugged it
does not heat the oven contents and has loud hum
Is it dead(how to make sure) or perhaps requires say 1v higher cathode
heating voltage than what transformer supplies?

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