A few days ago we had a shock when our Samsung microwave oven switched
itself on without anyone being near it.
There were only my wife and myself in the house and we were nowhere
near the kitchen, when we both heard the `beeping` sounds of the
buttons being pressed,followed by the sound of the oven running. we
both went into the kitchen to find that it had programmed itself to
run for about 2 minutes, as the count down timer was on 1 minute 45
seconds. We watched in amazement while the timer counted down to zero
and the oven stopped.
How could this happen, and can the `beeps` of the buttons being
pressed be caused by a fault, or do the buttons have to be pressed to
make the beeps.
It made the usual 4 or 5 beeps as when we use it normally,except that
there was no-one in the vicinity,
Needless to say, we have unplugged the thing,untill we find the cause.

Eric Bradley wrote:
It made the usual 4 or 5 beeps as when we use it normally,except that
there was no-one in the vicinity,

You didn't mention whether anyone else was in the house, or could have
been (e.g., prankish intruder).

Needless to say, we have unplugged the thing,untill we find the cause.

Occam would suggest that human involvement, however unlikely, is less
unlikely than spontaneous sequential button pushing.

--
John Miller
email address: domain, n4vu.com; username, jsm
Surplus (FSoT):
New Conn V1 double trumpet case, no logo
Tektronix 465B oscilloscope

Sorry I can not help you with your two minute problem,

But NEVER run the microwave without something in it, you will burn out the
magnetron



"Eric Bradley" wrote in message
om...
A few days ago we had a shock when our Samsung microwave oven switched
itself on without anyone being near it.
There were only my wife and myself in the house and we were nowhere
near the kitchen, when we both heard the `beeping` sounds of the
buttons being pressed,followed by the sound of the oven running. we
both went into the kitchen to find that it had programmed itself to
run for about 2 minutes, as the count down timer was on 1 minute 45
seconds. We watched in amazement while the timer counted down to zero
and the oven stopped.
How could this happen, and can the `beeps` of the buttons being
pressed be caused by a fault, or do the buttons have to be pressed to
make the beeps.
It made the usual 4 or 5 beeps as when we use it normally,except that
there was no-one in the vicinity,
Needless to say, we have unplugged the thing,untill we find the cause.


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"Eric" wrote in message
...
Sorry I can not help you with your two minute problem,

But NEVER run the microwave without something in it, you will burn out the
magnetron



There may be some truth to this myth, but I've run microwaves without
anything in them a number of times as well as trying various metallic
objects in a discarded oven, never did have one damaged from it.

That's what I was thinking John,

But only Eric knows how true this could be,
In which case, I wonder if the keypad could of gone faulty, this is why I
like to unplug the primary side of the magnetron transformer when ever I
work on microwaves, they give me the ****s, until I am about to screw the
cover back on.



"John Miller" wrote in message
...
Eric Bradley wrote:
It made the usual 4 or 5 beeps as when we use it normally,except that
there was no-one in the vicinity,

You didn't mention whether anyone else was in the house, or could have
been (e.g., prankish intruder).

Needless to say, we have unplugged the thing,untill we find the cause.

Occam would suggest that human involvement, however unlikely, is less
unlikely than spontaneous sequential button pushing.

--
John Miller
email address: domain, n4vu.com; username, jsm
Surplus (FSoT):
New Conn V1 double trumpet case, no logo
Tektronix 465B oscilloscope


---
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Hi!

There may be some truth to this myth, but I've run microwaves without
anything in them a number of times as well as trying various metallic
objects in a discarded oven, never did have one damaged from it.

Maybe nobody cares...but here are two true stories of "abused" microwaves...

I believed this until one night my little brothers got into an old Kenmore
microwave that I was cleaning up. They basically punched all nines on the
keypad and set it to go. It had been running empty for a little over 30
minutes when I found it. The fan and magnetron had stopped, but the light
was on inside. The smell around it suggested that something had cooked
bigtime, but after letting it cool down everything was fine once again. It's
still working to this day and will have 20 years on it come 2005.

My grandmother bought a Litton microwave some awful number of years ago
(really old machine...has a rotary timer on it!) and one of the first things
she did (before reading the directions) was to put a large metal cooking pot
inside. She started the oven and BANG...I've been told that it blew the
glass out of the door. She had it fixed, and to this day it is also still
running like new. I'd guess that it is at least 30 years old now...

William

"William R. Walsh" m writes:

Hi!

There may be some truth to this myth, but I've run microwaves without
anything in them a number of times as well as trying various metallic
objects in a discarded oven, never did have one damaged from it.

Maybe nobody cares...but here are two true stories of "abused" microwaves...

I believed this until one night my little brothers got into an old Kenmore
microwave that I was cleaning up. They basically punched all nines on the
keypad and set it to go. It had been running empty for a little over 30
minutes when I found it. The fan and magnetron had stopped, but the light
was on inside. The smell around it suggested that something had cooked
bigtime, but after letting it cool down everything was fine once again. It's
still working to this day and will have 20 years on it come 2005.

My grandmother bought a Litton microwave some awful number of years ago
(really old machine...has a rotary timer on it!) and one of the first things
she did (before reading the directions) was to put a large metal cooking pot
inside. She started the oven and BANG...I've been told that it blew the
glass out of the door. She had it fixed, and to this day it is also still
running like new. I'd guess that it is at least 30 years old now...

But it DID blow the glass out of the dooe.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
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On Sat, 25 Sep 2004 23:18:31 GMT, "James Sweet"

There may be some truth to this myth, but I've run microwaves without
anything in them a number of times as well as trying various metallic
objects in a discarded oven, never did have one damaged from it.


Running a microwave empty is bad for it because there's nothing to
absorb the 700 Watts of microwave power coming out of the magnetron,
so it all ends up going back into the magnetron. Eventually it will
heat up enough to either trip the thermal breaker, or destroy the
magnetron. Nothing will explode though.

The dangers of putting metal objects in the microwave is more of a
myth. It's true that certain things like crumpled foil will cause
arcing, but this isn't dangerous and shouldn't hurt the oven. Things
like metal twist ties can heat up and catch on fire. Keep in mind
that the oven walls are made of metal and metal temperature probes
have been around for years. You're generally ok with flat metal
objects, or even things like spoons and wire racks. You don't want to
use metal pots because they will shield the thing you're trying to
cook from the RF.
Andy Cuffe

"Eric" wrote in message
...
That's what I was thinking John,

But only Eric knows how true this could be,
In which case, I wonder if the keypad could of gone faulty, this is why I
like to unplug the primary side of the magnetron transformer when ever I
work on microwaves, they give me the ****s, until I am about to screw the
cover back on.




Did someone happen to clean the control panel with spray cleaner? Depending
on the design, some moisture may have run down into the keypad and caused
random button presses.

I heard of someone how used to wreck microwaves, he thought he had to "pre
heat" them for a few minutes.



"James Sweet" wrote in message
news:b1n5d.2873$Wu1.2825@trnddc02...

"Eric" wrote in message
...
Sorry I can not help you with your two minute problem,

But NEVER run the microwave without something in it, you will burn out the
magnetron



There may be some truth to this myth, but I've run microwaves without
anything in them a number of times as well as trying various metallic
objects in a discarded oven, never did have one damaged from it.




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We use the microwave at work to destroy recordable CDs. About 5
seconds give a nice light show as the subtrate build up a charge and
starts arcing internally. It very nicely destroys the disk and
usually the layers will separate.




On Sat, 25 Sep 2004 23:26:59 -0400, Andy Cuffe
wrote:

On Sat, 25 Sep 2004 23:18:31 GMT, "James Sweet"

There may be some truth to this myth, but I've run microwaves without
anything in them a number of times as well as trying various metallic
objects in a discarded oven, never did have one damaged from it.


Running a microwave empty is bad for it because there's nothing to
absorb the 700 Watts of microwave power coming out of the magnetron,
so it all ends up going back into the magnetron. Eventually it will
heat up enough to either trip the thermal breaker, or destroy the
magnetron. Nothing will explode though.

The dangers of putting metal objects in the microwave is more of a
myth. It's true that certain things like crumpled foil will cause
arcing, but this isn't dangerous and shouldn't hurt the oven. Things
like metal twist ties can heat up and catch on fire. Keep in mind
that the oven walls are made of metal and metal temperature probes
have been around for years. You're generally ok with flat metal
objects, or even things like spoons and wire racks. You don't want to
use metal pots because they will shield the thing you're trying to
cook from the RF.
Andy Cuffe

"Eric" wrote in message
...
I heard of someone how used to wreck microwaves, he thought he had to "pre
heat" them for a few minutes.




Well if you run them for a few *minutes* with nothing in them as someone
else said, it can overheat the magnetron, but a few, or even tens of seconds
generally won't cause any problems.

what's wrong with people at this group?


The person who started this topic said the microwave ran for two minutes.
that's when I added my warning.






"James Sweet" wrote in message
news:4gu5d.1140$ku4.144@trnddc01...

"Eric" wrote in message
...
I heard of someone how used to wreck microwaves, he thought he had to "pre
heat" them for a few minutes.




Well if you run them for a few *minutes* with nothing in them as someone
else said, it can overheat the magnetron, but a few, or even tens of seconds
generally won't cause any problems.




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Andy Cuffe wrote:
On Sat, 25 Sep 2004 23:18:31 GMT, "James Sweet"

There may be some truth to this myth, but I've run microwaves without
anything in them a number of times as well as trying various metallic
objects in a discarded oven, never did have one damaged from it.



Running a microwave empty is bad for it because there's nothing to
absorb the 700 Watts of microwave power coming out of the magnetron,
so it all ends up going back into the magnetron. Eventually it will
heat up enough to either trip the thermal breaker, or destroy the
magnetron. Nothing will explode though.

Nope! There is nothing inside the magnetron that can absorb power. All that
happens to any microwaves that head back towards the magnetron cavity
is they reflect back into the oven. Unless something that absorbs microwaves
is put into the cavity, the 700W is never created. The oven is a resonant
cavity with very high Q. What does happen when the cavity is left unloaded,
is very high voltage nodes are setup in the cavity space. Depending on
where they happen to be, some arcing might occur. The oven's designers
were very careful to make sure that that doesn't happen. Modern ovens
are designed to withstand being run empty indefinitely.

When you put metal objects into a microwave oven, again, you run the risk
of causing localized areas of high voltage, that may cause arcing. You
also will get localized areas of high current on the metal object which
may cause parts of it to get extremely hot.

-Chuck

[This followup was posted to sci.electronics.repair and a copy was sent
to the cited author.]

In article ,
says...
A few days ago we had a shock when our Samsung microwave oven switched
itself on without anyone being near it.
There were only my wife and myself in the house and we were nowhere
near the kitchen, when we both heard the `beeping` sounds of the
buttons being pressed,followed by the sound of the oven running. we
both went into the kitchen to find that it had programmed itself to
run for about 2 minutes, as the count down timer was on 1 minute 45
seconds. We watched in amazement while the timer counted down to zero
and the oven stopped.
How could this happen, and can the `beeps` of the buttons being
pressed be caused by a fault, or do the buttons have to be pressed to
make the beeps.
It made the usual 4 or 5 beeps as when we use it normally,except that
there was no-one in the vicinity,
Needless to say, we have unplugged the thing,untill we find the cause.

Does it have a delay start mode, where you can tell it to start
running at a certain time? Maybe somebody accidently set that mode by
hitting the wrong keys, and it later finished that program?

--
If there is a no_junk in my address, please REMOVE it before replying!
All junk mail senders will be prosecuted to the fullest extent of the
law!!
http://home.att.net/~andyross

Hi!

But it DID blow the glass out of the dooe.

To be honest with you, I don't know if that's impossible or not...the whole
thing happened a good while before I was even alive and I'm sure it's one of
those stories that gets a little better each time it's told.

All I can say for sure is that the microwave was somehow seriously damaged
and it was repaired...and that it still runs today without any lasting
effect.

William

"William R. Walsh" m writes:

Hi!

But it DID blow the glass out of the dooe.

To be honest with you, I don't know if that's impossible or not...the whole
thing happened a good while before I was even alive and I'm sure it's one of
those stories that gets a little better each time it's told.

All I can say for sure is that the microwave was somehow seriously damaged
and it was repaired...and that it still runs today without any lasting
effect.

So, it's possible the magnetron was replaced?

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header is ignored.
To contact me, please use the feedback form on the S.E.R FAQ Web sites.

"Eric" wrote in message
...
what's wrong with people at this group?


The person who started this topic said the microwave ran for two minutes.
that's when I added my warning.



He never said it failed either, he unplugged it and hasn't used it since.

In article ,
says...
A few days ago we had a shock when our Samsung microwave oven switched
itself on without anyone being near it.
(snip)

I would dismantle and thoroughly clean the control panel with alcohol
- if possible. If it is damaged (e.g. buttons are in permanent
contact, and /or can't be dismantled further for re-gapping of
contacts) you may have to salvage a panel from a junk unit of the same
model as ordering a new part would probably exceed the cost of a new
oven (that is if the spares are even available). *Read the FAQ for
important safety guidelines as these units can kill.*

Ben

I know, I know they have unplugged it, but they were watching it for a
couple of minutes, while it counted down, I take it there was nothing in the
microwave, that is why I gave the warning.



"James Sweet" wrote in message
news:eXO5d.3846$8H1.594@trnddc08...

"Eric" wrote in message
...
what's wrong with people at this group?


The person who started this topic said the microwave ran for two minutes.
that's when I added my warning.



He never said it failed either, he unplugged it and hasn't used it since.




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Don't know where you guys are from, i'm guessing the US, but at the moment
on Sky TV in the UK there's a program called "Brainiacs: Science Abuse".

Needless to say one of the featurettes they have every week is to put
various things in the Microwave that you clearly shouldn't to see what
happens.

Most of them involve the "Brainiac" being well out of the vicinity, if not
running. Many also cause the microwave oven to quite literally explode.
Obviously some of the substances would be pretty unstable whatever you did
to them.

Fairly irrelevent to this guys keypad problem but all the talk of what you
should or shouldn't do to / with a microwave reminded me of it.

:O)

Martin.



"Andy Cuffe" wrote in message
...
On Sat, 25 Sep 2004 23:18:31 GMT, "James Sweet"

There may be some truth to this myth, but I've run microwaves without
anything in them a number of times as well as trying various metallic
objects in a discarded oven, never did have one damaged from it.


Running a microwave empty is bad for it because there's nothing to
absorb the 700 Watts of microwave power coming out of the magnetron,
so it all ends up going back into the magnetron. Eventually it will
heat up enough to either trip the thermal breaker, or destroy the
magnetron. Nothing will explode though.

The dangers of putting metal objects in the microwave is more of a
myth. It's true that certain things like crumpled foil will cause
arcing, but this isn't dangerous and shouldn't hurt the oven. Things
like metal twist ties can heat up and catch on fire. Keep in mind
that the oven walls are made of metal and metal temperature probes
have been around for years. You're generally ok with flat metal
objects, or even things like spoons and wire racks. You don't want to
use metal pots because they will shield the thing you're trying to
cook from the RF.
Andy Cuffe