Hi all,

We got a call from my (86 year old) Mum today to say that she saw
smoke coming out of her microwave so she unplugged it and carried it
out into the garden!

It's not a modern lightweight jobby either, a pretty substantial one
we bought her around 30 years ago.

Now she knows not to put anything metal in it and has been using it
for 30 years (after all), and was apparently, just warming some soup
when it happened. The only 'thing' is that she also left a light,
clear plastic food tub / punnet in there as well (she didn't spot it
because it was transparent) but that didn't seem to have suffered so
presumably didn't get hot itself?

Can anyone suggest what happened from this picture (taken looking up
inside at the top):?

https://dl.dropboxusercontent.com/u/.../Microwave.jpg

Is that circle the output port of the magnetron you can see though the
hole?

A question this raises is that are old microwaves a fire risk (and if
so why), as ours is probably older than mums was. We did try to find a
more colour coordinated microwave the last time we decorated the
kitchen but couldn't find anything that was as substantial and
capacious without being more complicated or expensive. ;-(

Cheers, T i m

T i m a écrit :
Can anyone suggest what happened from this picture (taken looking up
inside at the top):?

https://dl.dropboxusercontent.com/u/.../Microwave.jpg

Is that circle the output port of the magnetron you can see though the
hole?

The magnetron is usually at the side, working through an RF transparent
;window. That looks as if it could be the result of the rusting oven
liner, making poor contact with the rest of the lining. That would
concentrate the heating effect, causing a blast such as that. Or
perhaps a spoon was left in a bowl and that made contact with the
lining.

On Tue, 24 May 2016 22:30:18 +0100, Harry Bloomfield
wrote:

T i m a écrit :
Can anyone suggest what happened from this picture (taken looking up
inside at the top):?

https://dl.dropboxusercontent.com/u/.../Microwave.jpg

Is that circle the output port of the magnetron you can see though the
hole?

The magnetron is usually at the side, working through an RF transparent
;window.

I can't remember what else was inside other than the 'plastic' panel
at the top, part of which you saw melted.

That looks as if it could be the result of the rusting oven
liner, making poor contact with the rest of the lining.

Ok.

That would
concentrate the heating effect, causing a blast such as that.

[1]

I don't think it made a noise as such (although you might have
expected it to have done, looking at that damage) and (luckily?) Mum
was in the kitchen at the time and although a bit 'mutton' these days,
would probably have heard that?

Or
perhaps a spoon was left in a bowl and that made contact with the
lining.

Well, again, I wasn't there so only have her word for it but she
assures us that she was just doing what she has always done and
because it's (was) a pretty big oven, would have taken a fair sized
spoon to have gone anywhere near the sides (and certainly the top) if
left in a bowl?

FWIW, we replaced one of the two series 120V (or whatever they were)
lamps a few years back and cleaned it out while we were there (there
was a fair bit of 'fluff' over things). It amazed us just how well
everything was made and how clean it still was (considering it has
been used in a kitchen for 30 years). ;-)

Cheers, T i m

[1] "These blast points... too accurate for Sand People. Only Imperial
stormtroopers are so precise." By ? ;-)

On Tuesday, 24 May 2016 19:53:52 UTC+1, T i m wrote:

A question this raises is that are old microwaves a fire risk (and if
so why), as ours is probably older than mums was. We did try to find a

All cooking devices are a fire risk. Microwaves are massively safer than flame based methods.

Current microwaves are marginally safer due to a HV fuse, but not by much.


NT

On Tue, 24 May 2016 15:29:05 -0700 (PDT), wrote:

On Tuesday, 24 May 2016 19:53:52 UTC+1, T i m wrote:

A question this raises is that are old microwaves a fire risk (and if
so why), as ours is probably older than mums was. We did try to find a

All cooking devices are a fire risk.

And some clothes drying and mobile telephone devices of course. ;-(

Microwaves are massively safer than flame based methods.

Makes sense.

Current microwaves are marginally safer due to a HV fuse, but not by much.

I don't think it's something you hear of much though is it?

Cheers, T i m

On Tuesday, 24 May 2016 19:53:52 UTC+1, T i m wrote:
Hi all,

We got a call from my (86 year old) Mum today to say that she saw
smoke coming out of her microwave so she unplugged it and carried it
out into the garden!

It's not a modern lightweight jobby either, a pretty substantial one
we bought her around 30 years ago.

Now she knows not to put anything metal in it and has been using it
for 30 years (after all), and was apparently, just warming some soup
when it happened. The only 'thing' is that she also left a light,
clear plastic food tub / punnet in there as well (she didn't spot it
because it was transparent) but that didn't seem to have suffered so
presumably didn't get hot itself?

Can anyone suggest what happened from this picture (taken looking up
inside at the top):?

https://dl.dropboxusercontent.com/u/.../Microwave.jpg

Is that circle the output port of the magnetron you can see though the
hole?

A question this raises is that are old microwaves a fire risk (and if
so why), as ours is probably older than mums was. We did try to find a
more colour coordinated microwave the last time we decorated the
kitchen but couldn't find anything that was as substantial and
capacious without being more complicated or expensive. ;-(

Cheers, T i m

It's probably worth getting a new microwave with a metal cabinet rather than plastic. (Re. Fire safety)

I had an old philips go like this many years ago. The bloke who condemned it
suggested that the rust on the microwave door seals might have changed the
cavity perameters enough to cause hot spots to move. I'm assuming he meant
standing waves or reflected power back into the magnetron area. It was a
strange beast as it had no turntable but a rotating aerial which of course
was never as good as a turntable. I cannot see your picture obviously, but
there are so many things that can cause reflected power to be in the wrong
place, that you may never know. Most things in microwaves are supposed to be
non flamable but presumably that does not mean melting will not happen if
they get hot enough!
I now have a talking one from Cobolt.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
wrote in message
...
On Tuesday, 24 May 2016 19:53:52 UTC+1, T i m wrote:

A question this raises is that are old microwaves a fire risk (and if
so why), as ours is probably older than mums was. We did try to find a

All cooking devices are a fire risk. Microwaves are massively safer than
flame based methods.

Current microwaves are marginally safer due to a HV fuse, but not by much.


NT

On Wednesday, 25 May 2016 08:02:26 UTC+1, harry wrote:
On Tuesday, 24 May 2016 19:53:52 UTC+1, T i m wrote:
Hi all,

We got a call from my (86 year old) Mum today to say that she saw
smoke coming out of her microwave so she unplugged it and carried it
out into the garden!

It's not a modern lightweight jobby either, a pretty substantial one
we bought her around 30 years ago.

Now she knows not to put anything metal in it and has been using it
for 30 years (after all), and was apparently, just warming some soup
when it happened. The only 'thing' is that she also left a light,
clear plastic food tub / punnet in there as well (she didn't spot it
because it was transparent) but that didn't seem to have suffered so
presumably didn't get hot itself?

Can anyone suggest what happened from this picture (taken looking up
inside at the top):?

https://dl.dropboxusercontent.com/u/.../Microwave.jpg

Is that circle the output port of the magnetron you can see though the
hole?

A question this raises is that are old microwaves a fire risk (and if
so why), as ours is probably older than mums was. We did try to find a
more colour coordinated microwave the last time we decorated the
kitchen but couldn't find anything that was as substantial and
capacious without being more complicated or expensive. ;-(

Cheers, T i m

It's probably worth getting a new microwave with a metal cabinet rather than plastic. (Re. Fire safety)

I've never seen one with a plastic case.


NT

On Tue, 24 May 2016 19:53:50 +0100, T i m wrote:

Now she knows not to put anything metal in it and has been using it
for 30 years (after all), and was apparently, just warming some soup
when it happened. The only 'thing' is that she also left a light,
clear plastic food tub / punnet in there as well (she didn't spot it
because it was transparent) but that didn't seem to have suffered so
presumably didn't get hot itself?

Can anyone suggest what happened from this picture (taken looking up
inside at the top):?

When reheating some foods, especially those with membranes such as
eggs or potatoes they will often produce mini "explosions" scattering
bits of food around the cooker. If a large lump sticks to the surface
it can overheat and burn some time later. (You can see some smaller
bits in the picture so this has happened in the past). If it sticks
to the roof it often wont be noticed but can overheat.

I'm assuming this is a microwave with a roof mounted feed and possibly
a stirrer fan such as shown here :-

http://www.todayifoundout.com/wp-con...3262845786.jpg
and here
http://diy.stackexchange.com/questio...the-mode-stirr

The stirrer fan scatters the microwaves around, some are driven by a
small motor, others by a belt from the cooling motor and some revolve
in the cooling air. They often stick and debris can build up causing
sparking. It is usual not to notice if they stick as you can't see
them revolving and cooking performance isn't badly impaired - they
will however produce localised hot spots.

Replacing the stirrer fan blade and making sure it is free as well as
replacing the top plastic cover will probably restore it to life.

The fire risk by the way is negligible. The plastic is self
extinguishing and once power goes off the small amount of burning will
soon stop.

On Wed, 25 May 2016 08:04:14 +0100, "Brian Gaff"
wrote:

I had an old philips go like this many years ago. The bloke who condemned it
suggested that the rust on the microwave door seals might have changed the
cavity perameters enough to cause hot spots to move. I'm assuming he meant
standing waves or reflected power back into the magnetron area.

Yes, I was aware of things causing issues like that and have no way of
knowing if Mum left something else in there that caused such
reflections.

It was a
strange beast as it had no turntable but a rotating aerial which of course
was never as good as a turntable.

Understood. This one has (had) a big glass turntable but I don't know
if it also had the stirrer fan / rotating aerial (as mentioned later
in the thread).

I cannot see your picture obviously,

Basically it looks like there is a 'non metal' panel in the middle of
the roof of the microwave and offset from the middle was a fairly
clean round hole about the size of a 50p piece right through the
plastic. The plastic food container Mum left in there accidentally
(she keeps the (microwave use) food cover stacking tray and a couple
of other things in there between uses) had some of the plastic from
whatever fell out of the roof in it and the edges of the hole have
some drippage, as would be typical of some thermo plastic that had hot
very hot. There is also some smoke damage around the hole.


but
there are so many things that can cause reflected power to be in the wrong
place, that you may never know.

That is where we are I think Brian. The microwave went straight down
the dump (daughter was going that way) so I'll not have chance to see
what happened.

Most things in microwaves are supposed to be
non flamable but presumably that does not mean melting will not happen if
they get hot enough!

Yes, I don't think there was an actual risk of a fire because I think
it was all over once the bit that melted actually melted.

I now have a talking one from Cobolt.

That's cool.

Mum would need one with a very loud voice! ;-)

It's funny. She's never worked in an office or needed to use a
typewriter but because her hearing isn't so good she can communicate
easier with us by typing on the likes of MSN Messenger now Skype than
she can on the phone. We just have to be patient re waiting for a
reply. ;-)

Cheers, T i m

On Wed, 25 May 2016 09:02:02 +0100, Peter Parry
wrote:

On Tue, 24 May 2016 19:53:50 +0100, T i m wrote:

Now she knows not to put anything metal in it and has been using it
for 30 years (after all), and was apparently, just warming some soup
when it happened. The only 'thing' is that she also left a light,
clear plastic food tub / punnet in there as well (she didn't spot it
because it was transparent) but that didn't seem to have suffered so
presumably didn't get hot itself?

Can anyone suggest what happened from this picture (taken looking up
inside at the top):?

When reheating some foods, especially those with membranes such as
eggs or potatoes they will often produce mini "explosions" scattering
bits of food around the cooker.

Understood.

If a large lump sticks to the surface
it can overheat and burn some time later. (You can see some smaller
bits in the picture so this has happened in the past).

Seen.

If it sticks
to the roof it often wont be noticed but can overheat.

Understood.

I'm assuming this is a microwave with a roof mounted feed and possibly
a stirrer fan such as shown here :-

http://www.todayifoundout.com/wp-con...3262845786.jpg
and here
http://diy.stackexchange.com/questio...the-mode-stirr

Interesting, thanks.

It did have a turntable if the two tend to be mutually exclusive?

The stirrer fan scatters the microwaves around, some are driven by a
small motor, others by a belt from the cooling motor and some revolve
in the cooling air. They often stick and debris can build up causing
sparking.

Understood.

It is usual not to notice if they stick as you can't see
them revolving and cooking performance isn't badly impaired - they
will however produce localised hot spots.

Understood. Mums oven had quite a large 'plastic' panel in the middle
of the roof (150 x 100 possibly) whereas ours is a much smaller one
(75 x 60).

Replacing the stirrer fan blade and making sure it is free as well as
replacing the top plastic cover will probably restore it to life.

Ignoring the fairly large hole that is now in the roof you mean. ;-)

The fire risk by the way is negligible. The plastic is self
extinguishing and once power goes off the small amount of burning will
soon stop.

Understood. I would have thought that was the case and I don't think
Mum did anything in the way of extinguishing any flames and the
'damage' looked pretty localised.

If it wasn't for the fact it had a hole burned though, it being pretty
old, it not been a 'microwave' and if I had more time to play with
such things, I would have kept hold of it and taken it to bits to see
if I could see how that particular one worked and what went wrong.

Cheers, T i m

On Wednesday, 25 May 2016 09:02:06 UTC+1, Peter Parry wrote:
On Tue, 24 May 2016 19:53:50 +0100, T i m wrote:

Now she knows not to put anything metal in it and has been using it
for 30 years (after all), and was apparently, just warming some soup
when it happened. The only 'thing' is that she also left a light,
clear plastic food tub / punnet in there as well (she didn't spot it
because it was transparent) but that didn't seem to have suffered so
presumably didn't get hot itself?

Can anyone suggest what happened from this picture (taken looking up
inside at the top):?

When reheating some foods, especially those with membranes such as
eggs or potatoes they will often produce mini "explosions" scattering
bits of food around the cooker. If a large lump sticks to the surface
it can overheat and burn some time later. (You can see some smaller
bits in the picture so this has happened in the past). If it sticks
to the roof it often wont be noticed but can overheat.

Overheat and catch fire. I had that at the weekend.
About 3am I wanted a toasted cheese sandwich but the butter was in the fridge, I usally get it out cut a pit off put it on a saucer and microwave it for 109 seconds or so a few times until is's softened up a bit.
But this time as there was only a bit left in the wrapper...
It was anchor butter, I set the microwave to 90w (lowest setting) and about 15 seconds also the lowest setting, I set it off and ion under 5 mins there were flames fare larger than I'd expect from 1/10th of the normal size block of butter.
I placed another saucer over the burning mound and then checked it all in the sink.

On Wed, 25 May 2016 10:27:52 +0100, T i m wrote:

It did have a turntable if the two tend to be mutually exclusive?

No, having both wasn't uncommon.

On Wed, 25 May 2016 10:27:52 +0100, T i m wrote:


If it wasn't for the fact it had a hole burned though, it being pretty
old, it not been a 'microwave' and if I had more time to play with
such things, I would have kept hold of it and taken it to bits to see
if I could see how that particular one worked and what went wrong.

The transformers are well worth keeping if you fancy playing with
lethal very high voltages (2 to 3 kV). Alternatively they can be
turned into excellent spot welders.

On Wed, 25 May 2016 16:12:54 +0100, Peter Parry
wrote:

On Wed, 25 May 2016 10:27:52 +0100, T i m wrote:


If it wasn't for the fact it had a hole burned though, it being pretty
old, it not been a 'microwave' and if I had more time to play with
such things, I would have kept hold of it and taken it to bits to see
if I could see how that particular one worked and what went wrong.

The transformers are well worth keeping if you fancy playing with
lethal very high voltages (2 to 3 kV). Alternatively they can be
turned into excellent spot welders.

'Normally' (before realising I don't have enough hours left in my life
to do all the things I've got to do, let alone want or would like to
do ...) I would have taken it to pieces and played with it all.

However, our daughter was there (and knowing the above) offered to
take it away ...

Cheers, T i m

whisky-dave wrote:
On Wednesday, 25 May 2016 09:02:06 UTC+1, Peter Parry wrote:

On Tue, 24 May 2016 19:53:50 +0100, T i wrote:


Now she knows not to put anything metal in it and has been using it
for 30 years (after all), and was apparently, just warming some soup
when it happened. The only 'thing' is that she also left a light,
clear plastic food tub / punnet in there as well (she didn't spot it
because it was transparent) but that didn't seem to have suffered so
presumably didn't get hot itself?

Can anyone suggest what happened from this picture (taken looking up
inside at the top):?

When reheating some foods, especially those with membranes such as
eggs or potatoes they will often produce mini "explosions" scattering
bits of food around the cooker. If a large lump sticks to the surface
it can overheat and burn some time later. (You can see some smaller
bits in the picture so this has happened in the past). If it sticks
to the roof it often wont be noticed but can overheat.

Overheat and catch fire. I had that at the weekend.
About 3am I wanted a toasted cheese sandwich but the butter was in the fridge, I usally get it out cut a pit off put it on a saucer and microwave it for 109 seconds or so a few times until is's softened up a bit.
But this time as there was only a bit left in the wrapper...
It was anchor butter, I set the microwave to 90w (lowest setting) and about 15 seconds also the lowest setting, I set it off and ion under 5 mins there were flames fare larger than I'd expect from 1/10th of the normal size block of butter.
I placed another saucer over the burning mound and then checked it all in the sink.



It overheated because it has on/off cycling control, not
proportional. AFAIK only Panasonic has proportional control these days
and their reliability seems a bit iffy. That's why I have repaired our
old Belling, because its LOW setting actually is.

Peter Parry wrote:
On Wed, 25 May 2016 10:27:52 +0100, T i wrote:


If it wasn't for the fact it had a hole burned though, it being pretty
old, it not been a 'microwave' and if I had more time to play with
such things, I would have kept hold of it and taken it to bits to see
if I could see how that particular one worked and what went wrong.

The transformers are well worth keeping if you fancy playing with
lethal very high voltages (2 to 3 kV). Alternatively they can be
turned into excellent spot welders.

Have you a link to a design for the welder?

On Wednesday, 25 May 2016 09:59:27 UTC+1, T i m wrote:
On Wed, 25 May 2016 08:04:14 +0100, "Brian Gaff"

The usual cause is food stuck on the plastic outlet cover.

The microwave went straight down
the dump (daughter was going that way) so I'll not have chance to see
what happened.

All you need do to give it more life is remove the burnt cover. People are in such a rush to chuck away what they paid for.


Yes, I don't think there was an actual risk of a fire because I think
it was all over once the bit that melted actually melted.

Microwaves do cause fires, they're just less likely to than other cooker types, as they're more contained.


NT

On Wednesday, 25 May 2016 17:32:16 UTC+1, Capitol wrote:
Peter Parry wrote:
On Wed, 25 May 2016 10:27:52 +0100, T i wrote:


If it wasn't for the fact it had a hole burned though, it being pretty
old, it not been a 'microwave' and if I had more time to play with
such things, I would have kept hold of it and taken it to bits to see
if I could see how that particular one worked and what went wrong.

The transformers are well worth keeping if you fancy playing with
lethal very high voltages (2 to 3 kV). Alternatively they can be
turned into excellent spot welders.

Have you a link to a design for the welder?

Just rewind the transformer secondary with a few turns of welding flex. Be sure to keep the transformer thermal cutout in circuit. A mains switch is necessary, don't leave it on when not welding. Simple.

Compared to a standard 40A arc welder:
They don't run long before overheating.
less power
less open circuit voltage makes them a bit harder to get the arc going.

Better is one where you put 2 MOTs in series on 240v, and the rewound secondaries in series. Less transformer heating, more power. Adding a fan that runs when the welder's not on cools quicker.


NT

On Wed, 25 May 2016 17:32:04 +0100, Capitol wrote:

Peter Parry wrote:

The transformers are well worth keeping if you fancy playing with
lethal very high voltages (2 to 3 kV). Alternatively they can be
turned into excellent spot welders.

Have you a link to a design for the welder?

Do a Google search for " microwave transformer spot welder" (without
the quotes) will bring you pages of links and videos on the subject.
Basically you cut off the high voltage winding and substitute two
turns of large gauge copper wire. I used a piece of wire from an arc
welder as the secondary winding. It must be flexible enough to fit
around the transformer core. I first tried using a leftover length of
meter tail wire (25mm2) but that was far too rigid. A local welding
supplier found 2ft of arc welder lead of the same size but of hundreds
of strands of wire making it much more flexible.

On Wed, 25 May 2016 09:51:53 -0700 (PDT), wrote:

On Wednesday, 25 May 2016 09:59:27 UTC+1, T i m wrote:
On Wed, 25 May 2016 08:04:14 +0100, "Brian Gaff"

The usual cause is food stuck on the plastic outlet cover.

That could well have been the cause in this case but it would have
been the first time in 30 years (not that stops it being the case
etc).

The microwave went straight down
the dump (daughter was going that way) so I'll not have chance to see
what happened.

All you need do to give it more life is remove the burnt cover.

In hindsight you may have been right, but I was pretty sure a genuine
replacement (anything) wouldn't have been available and I wasn't sure
what I could have replaced it with that would have been 'safe' etc?

People are in such a rush to chuck away what they paid for.

People are (especially these days), I'm generally not, in fact I've
save many_an_item from being dumped, either directly or via Freecycle
etc.


Yes, I don't think there was an actual risk of a fire because I think
it was all over once the bit that melted actually melted.

Microwaves do cause fires, they're just less likely to than other cooker types, as they're more contained.

Understood.

As it happens, whilst the microwave was taken away by our daughter, it
hadn't been dumped yet so I got the chance to take it to bits tonight.
;-)

https://dl.dropboxusercontent.com/u/...rowave%202.jpg
https://dl.dropboxusercontent.com/u/...rowave%203.jpg
https://dl.dropboxusercontent.com/u/...rowave%204.jpg

I think it's done well to last 30 years and daughter has bought Mum a
replacement as she wanted to. ;-)

Cheers, T i m

p.s. Tonight I saved a Dyson DC04 from being dumped by stripping the
main beater-brush down and cleaning and re-lubing the bearings. It
probably needs a pair of belts as they have never been changed but it
seems to be going ok for now.

Peter Parry wrote:
On Wed, 25 May 2016 10:27:52 +0100, T i m wrote:


If it wasn't for the fact it had a hole burned though, it being pretty
old, it not been a 'microwave' and if I had more time to play with
such things, I would have kept hold of it and taken it to bits to see
if I could see how that particular one worked and what went wrong.

The transformers are well worth keeping if you fancy playing with
lethal very high voltages (2 to 3 kV). Alternatively they can be
turned into excellent spot welders.


I've often wondered... if microwave cookers have a removable magnetron that
has a highly directional output, could you break an egg on to a plate and
then cook it by waving the beam over the egg?

Not intending to try it but in theory, could you do that without frying
your own gonads (and other bits)?

Tim

--
Trolls and troll feeders go in my killfile

On Wednesday, 25 May 2016 19:44:09 UTC+1, T i m wrote:
On Wed, 25 May 2016 09:51:53 -0700 (PDT), tabbypurr wrote:
On Wednesday, 25 May 2016 09:59:27 UTC+1, T i m wrote:
On Wed, 25 May 2016 08:04:14 +0100, "Brian Gaff"

The usual cause is food stuck on the plastic outlet cover.

That could well have been the cause in this case but it would have
been the first time in 30 years (not that stops it being the case
etc).

it's normally what causes that

The microwave went straight down
the dump (daughter was going that way) so I'll not have chance to see
what happened.

All you need do to give it more life is remove the burnt cover.

In hindsight you may have been right,

and clean the carbon off the outlet

but I was pretty sure a genuine
replacement (anything) wouldn't have been available and I wasn't sure

no need for one

what I could have replaced it with that would have been 'safe' etc?

any plastic that doesn't heat up in a microwave, or you can buy mica-like sheet. Or simply nothing, it will then work ok for years until gunk buildup causes a repeat show.


People are in such a rush to chuck away what they paid for.

People are (especially these days), I'm generally not, in fact I've
save many_an_item from being dumped, either directly or via Freecycle
etc.


Yes, I don't think there was an actual risk of a fire because I think
it was all over once the bit that melted actually melted.

Microwaves do cause fires, they're just less likely to than other cooker types, as they're more contained.

Understood.

As it happens, whilst the microwave was taken away by our daughter, it
hadn't been dumped yet so I got the chance to take it to bits tonight.
;-)

https://dl.dropboxusercontent.com/u/...rowave%202.jpg
https://dl.dropboxusercontent.com/u/...rowave%203.jpg
https://dl.dropboxusercontent.com/u/...rowave%204.jpg

I think it's done well to last 30 years and daughter has bought Mum a
replacement as she wanted to. ;-)

Cheers, T i m

p.s. Tonight I saved a Dyson DC04 from being dumped by stripping the
main beater-brush down and cleaning and re-lubing the bearings. It
probably needs a pair of belts as they have never been changed but it
seems to be going ok for now.

It's daft what gets dumped.


NT

On Wednesday, 25 May 2016 19:59:21 UTC+1, Tim+ wrote:
Peter Parry wrote:
On Wed, 25 May 2016 10:27:52 +0100, T i m wrote:


If it wasn't for the fact it had a hole burned though, it being pretty
old, it not been a 'microwave' and if I had more time to play with
such things, I would have kept hold of it and taken it to bits to see
if I could see how that particular one worked and what went wrong.

The transformers are well worth keeping if you fancy playing with
lethal very high voltages (2 to 3 kV). Alternatively they can be
turned into excellent spot welders.


I've often wondered... if microwave cookers have a removable magnetron that
has a highly directional output, could you break an egg on to a plate and
then cook it by waving the beam over the egg?

that's pretty much how microwaving food began in the 30s.

Not intending to try it but in theory, could you do that without frying
your own gonads (and other bits)?

it's not really safe, but you can do it. They'll also light up dead discharge lightbulbs.


NT

On 25/05/16 19:55, Tim+ wrote:
Peter Parry wrote:
On Wed, 25 May 2016 10:27:52 +0100, T i m wrote:


If it wasn't for the fact it had a hole burned though, it being pretty
old, it not been a 'microwave' and if I had more time to play with
such things, I would have kept hold of it and taken it to bits to see
if I could see how that particular one worked and what went wrong.

The transformers are well worth keeping if you fancy playing with
lethal very high voltages (2 to 3 kV). Alternatively they can be
turned into excellent spot welders.


I've often wondered... if microwave cookers have a removable magnetron that
has a highly directional output, could you break an egg on to a plate and
then cook it by waving the beam over the egg?

Not intending to try it but in theory, could you do that without frying
your own gonads (and other bits)?

Given some basic microwaveguide and a suitable directional horn or
phased array, well yes.

Dont stand in front of a radar transmitter. People have died...


Tim



--
"It is an established fact to 97% confidence limits that left wing
conspirators see right wing conspiracies everywhere"

On 25/05/16 20:05, wrote:
p.s. Tonight I saved a Dyson DC04 from being dumped by stripping the
main beater-brush down and cleaning and re-lubing the bearings. It
probably needs a pair of belts as they have never been changed but it
seems to be going ok for now.
It's daft what gets dumped.

All Dysons should be dumped.
Britains own Apple. All fashion and form and **** all function.


--
Microsoft : the best reason to go to Linux that ever existed.

Chris Hogg wrote:
On Wed, 25 May 2016 17:31:08 +0100, wrote:


It overheated because it has on/off cycling control, not
proportional. AFAIK only Panasonic has proportional control these days
and their reliability seems a bit iffy. That's why I have repaired our
old Belling, because its LOW setting actually is.

Do you mean that, i.e. that Panny's have proportional control? If
you'd said only Panny's have cycling control, I'd have agreed with
you. We have an old Panny, at least 25 years old, maybe even 30, and
I'm sure it pulses, as milk about to boil over rises then falls back,
then rises again and so on, and you can hear a change in the sound, in
time with the milk rising and falling. Because of that, I reckon that
a short time of say a few seconds, on 'simmer' (it only has four
settings) puts in the same amount of power as the same time on full
power. Longer times give the pulsing a chance to take effect.


At least some recent Panasonics have proportional control where
you reduce the power to a continuous low level without pulsing. They do
it with an inverter design reducing the magnetron output power I
understand. Our Belling uses different values of series capacitance to
limit the current into the magnetron. We've had one capacitor failure in
40 years, plus a few bulbs. I can't comment on older Panasonic units
using pulse control. Maybe Apple/Dyson can look at the problem and set
the new(old) performance standards. I hate to think how many modern
microwave ovens I've had food explode in. People even sell food covers
for microwaves because of this control problem. On LOW, the Belling
never needs a food cover and is perfect for butter softening!

Tim+ wrote:
Peter wrote:

On Wed, 25 May 2016 10:27:52 +0100, T i wrote:


If it wasn't for the fact it had a hole burned though, it being pretty
old, it not been a 'microwave' and if I had more time to play with
such things, I would have kept hold of it and taken it to bits to see
if I could see how that particular one worked and what went wrong.

The transformers are well worth keeping if you fancy playing with
lethal very high voltages (2 to 3 kV). Alternatively they can be
turned into excellent spot welders.


I've often wondered... if microwave cookers have a removable magnetron that
has a highly directional output, could you break an egg on to a plate and
then cook it by waving the beam over the egg?

Not intending to try it but in theory, could you do that without frying
your own gonads (and other bits)?

Tim

Wear very thick insulated gloves!!

On Wed, 25 May 2016 18:55:40 -0000 (UTC), Tim+
wrote:


I've often wondered... if microwave cookers have a removable magnetron that
has a highly directional output, could you break an egg on to a plate and
then cook it by waving the beam over the egg?

In the army 4Mk7 radar the magnetron was stowed during transportation.
It just so happened that the wave guide, apart from leaking like a
sieve, also just fitted a Gingsters meat pie. On deployment you could
slide the meat pie into the wave guide and swing the magnetron back
into position. When the radar was fired up a few seconds would ensure
a very hot pie. Unfortunately, sometimes someone else turned the
radar on without knowing the pie was in position and after more than a
few seconds the whole site was covered in a fine smoke smelling
strongly of recently incinerated meat pie.

To make a portable egg cooker all you would need to add to the
magnetron is a horn to match the magnetron impedance to free air.

On Wed, 25 May 2016 12:05:12 -0700 (PDT), wrote:

snip

what I could have replaced it with that would have been 'safe' etc?

any plastic that doesn't heat up in a microwave, or you can buy mica-like sheet.

Hmmmm. Now, if it were mine I and in hindsight I might have tried
that. However, we already have a working microwave ...

Or simply nothing, it will then work ok for years until gunk buildup causes a repeat show.

We popped round to Mums tonight and I recovered the rogue plastic tub
that *may* have been party to the problem. Now I have had a proper
chance to de-brief Mum on what happened she said that she saw sparks
and then smelled the burning and saw flames inside the thing before
quickly turning it off. She then put the flames out with a wet cloth,
then took it outside in case anything had caught fire in the void at
the top.

snip

p.s. Tonight I saved a Dyson DC04 from being dumped by stripping the
main beater-brush down and cleaning and re-lubing the bearings. It
probably needs a pair of belts as they have never been changed but it
seems to be going ok for now.

It's daft what gets dumped.

It is, but you can understand why. Very few people these days have the
skills (or tools even) to do anything and have more disposable income
to spend on cheaper (now mostly what are considered 'disposable')
items.

The worst example of this are those who actually throw away (as
opposed to give away or re-cycle even) perfectly good stuff, simply
because it doesn't match their new colour scheme. I really think too
much importance is set on 'style' and 'fashion' forcing the weak
minded to do stuff they often can't really afford, simply to keep up
with the Jonses. The kids hate school uniform but then change into the
'uniform' fashion of the time?

Every house must (apparently) be empty of any signs that people
actually *live* there and be whatever colour we\\ they are told it
*must* be.

But I think it's like the idea of 'sealed for life' bearings versus
grease nipples. They stopped fitting grease nipples because few people
bothered to use them in any case. There are people who would *rather*
pay someone to fit a new bit than maintain the things they have
(something I will have to hold my hand up to when said things aren't
of interest to me or part of my skillset, like regularly preserving a
fence and then it rots away). ;-(

Cheers, T i m

On Wed, 25 May 2016 04:17:24 -0700 (PDT), whisky-dave
wrote:

snip

But this time as there was only a bit left in the wrapper...

So did you leave it in the wrapper in the microwave?

It was anchor butter, I set the microwave to 90w (lowest setting) and about 15 seconds also the lowest setting, I set it off and ion under 5 mins

Was it still running after 5 mins if only set to run for 15 seconds?

there were flames fare larger than I'd expect from 1/10th of the normal size block of butter.

So you *expected* flames during this procedure? ;-)

I placed another saucer over the burning mound and then checked it all in the sink.

Firestarter. ;-)

Cheers, T i m

On Thursday, 26 May 2016 00:21:07 UTC+1, T i m wrote:
On Wed, 25 May 2016 12:05:12 -0700 (PDT), tabbypurr wrote:

It's daft what gets dumped.

It is, but you can understand why.

Lack of the most elementary knowledge. What I regard as basic skill stuff. Everyone knows time is money, that's not the issue. Throwing out what you paid £60 for because the fuse needs replacing is... well, brainless. So much perfectly good stuff is simply dumped, much of it because people believe a lot of nonsense.


NT

On Wed, 25 May 2016 20:23:36 +0100, The Natural Philosopher wrote:

Dont stand in front of a radar transmitter. People have died...

And beware of ground level satellite up links. They can have some
fairly hefty ERPs.

--
Cheers
Dave.

On Wed, 25 May 2016 16:29:31 -0700 (PDT), wrote:

On Thursday, 26 May 2016 00:21:07 UTC+1, T i m wrote:
On Wed, 25 May 2016 12:05:12 -0700 (PDT), tabbypurr wrote:

It's daft what gets dumped.

It is, but you can understand why.

Lack of the most elementary knowledge.

Like I said then.

What I regard as basic skill stuff.

Like I said then. What *you*, *I*, and many others here would consider
'rudimentary is rocket science to many.

Everyone knows time is money, that's not the issue.

It is for some (along with all the other tings I mentioned).

Throwing out what you paid £60 for because the fuse needs replacing is... well, brainless.

Of course, but that's only valid if you know it's a fuse. I got a
Dyson cylinder cleaner off Freecycle that was 'broken'. The PO had
bought it new, it had gone wrong, they paid yo have it repaired and
later it went wrong again. Not wanting to spend whatever *again*,
they decided to buy a new one. Within about 5 seconds of getting it
home I diagnosed a fractured mains cable where it enters the moulded
plug, cut that off, fitted a new one and it's been fine ever since.

So much perfectly good stuff is simply dumped, much of it because people believe a lot of nonsense.

Or don't have the confidence, ability, strength, tools or time to
*try* to fix it themselves.

Like the DC04 I saved from the skip tonight. It was pretty well used
and the symptoms were that the brush wasn't rotating. It rotated when
you turned it by hand so it was presumed it wasn't seized.

I took the brush out (hard whilst the belt was in place) and span the
brush on it's bearing and could now fee that the bearings were tight.
How would anyone not familiar with such thinks know what felt 'right'
or not. I then pulled one end cap off, the shaft out of the brush and
then felt each bearing to find one nearly seized and noted the shaft
had been spinning in the bearing. How would any non engineer spot
that? I then rinsed the bearings though with some WD40 and blew them
out with an airline. I then put a drop of engine oil on each and
worked it in (for now).

Now, you can buy a new brush with new bearings and belts for about 7
quid on eBay and the parts individually for much more. The bets are
worn, the brush is worn, the shaft is worn and the bearings are worn.
So, you don't need to have the skills to understand how it goes
together or how to (try to) fix it, but you do have to know that you
can get the brush out with the belt on, as long as you can pull it
hard enough (or have the right tool of course).

Now, if you want to actually change both belts you have to get the
clutch out and strip that down (maybe another 10 parts) and put it all
back together again in the right order. Or you can buy a complete new
clutch with belts fitted for about 15 quid. However, that is only any
use if you have a long T15 driver and can get the knob off the
selector ... etc etc.

How many people would spend say £120 on a charger to help a friend
test a 36V Lithium battery pack ... or spend similar on a car coolant
pressure test kit that they may only use once (even if it would cost
60 quid to get done in the garage)?

You can still have all the gear but no idea (when or how to use it).

The number of times I've been with other people and asked to borrow
their multimeter to faultfind some equipment they have asked me to
look at, only to be told they don't have one? How can you own a house,
car or any electrical equipment and not own a multimeter! Just the
same as they can own a car and not own a foot pump, battery charger,
some jump leads or even the workshop manual I guess? ;-(

Cheers, T i m

On 26/05/16 00:29, wrote:
On Thursday, 26 May 2016 00:21:07 UTC+1, T i m wrote:
On Wed, 25 May 2016 12:05:12 -0700 (PDT), tabbypurr wrote:

It's daft what gets dumped.

It is, but you can understand why.

Lack of the most elementary knowledge. What I regard as basic skill
stuff. Everyone knows time is money, that's not the issue. Throwing
out what you paid £60 for because the fuse needs replacing is...
well, brainless. So much perfectly good stuff is simply dumped, much
of it because people believe a lot of nonsense.

Its worse. Given the cost of overheads in running a repair shop, you
probably want to charge around £60 an hour to fix stuff.

By the time you have talked to the customer, pulled the thing apart,
identified the blown part, which may or may not be obtainable, and may
be anything from pence top £150. and phoned the customer back 'I've
fixed it: That will be £120' and they say '**** that, I'll get a new one
- they're on sale at £90....and you are left with a repaired item you
cant sell for more than £30...

I have walked into my favourite PVC builder and walked out with a
perfectly good computer intact, and a monitor, simply because 'its a
customer trade in, and we cant sell it because its worthless'

Two RAM chips and an hour later and Linux Mint is flying in a machine
that last ran a virus raddled Windows XP.

Two hours of my time....would anyone pay me £120 for it? Nah.



NT



--
You can get much farther with a kind word and a gun than you can with a
kind word alone.

Al Capone

On 25/05/16 22:05, Peter Parry wrote:
On Wed, 25 May 2016 18:55:40 -0000 (UTC), Tim+
wrote:


I've often wondered... if microwave cookers have a removable magnetron that
has a highly directional output, could you break an egg on to a plate and
then cook it by waving the beam over the egg?

In the army 4Mk7 radar the magnetron was stowed during transportation.
It just so happened that the wave guide, apart from leaking like a
sieve, also just fitted a Gingsters meat pie. On deployment you could
slide the meat pie into the wave guide and swing the magnetron back
into position. When the radar was fired up a few seconds would ensure
a very hot pie. Unfortunately, sometimes someone else turned the
radar on without knowing the pie was in position and after more than a
few seconds the whole site was covered in a fine smoke smelling
strongly of recently incinerated meat pie.

To make a portable egg cooker all you would need to add to the
magnetron is a horn to match the magnetron impedance to free air.

+1. every home should have one...

--
"The great thing about Glasgow is that if there's a nuclear attack it'll
look exactly the same afterwards."

Billy Connolly

On Wed, 25 May 2016 21:25:08 +0100, pamela wrote:

snip

https://dl.dropboxusercontent.com/u/.../Microwave.jpg

snip

Corr! That's a very impressive hole in the inner casing in your
picture.

It is rather isn't it.

We had an incident here in which my dotty mum put a large metal
saucepan in our 1980s Panasonic microwave and ran it on full power
for several minutes!

Ouch.

The saucepan handle got badly charred and the microwave gave off a
terrible smell like a burnt out old telly for months after
whenever it was used

I bet.

Most amazing of all, the microwave continued to work perfectly.

It does say on most of the instructions that the machines can be
damaged after such events but that may be down to how well designed
they are ... if there is anything such as overload protection built in
etc?

I bet the insulation on the wiring inside the microwave may not
have been entirely intact after this but my dotty mum doesn't
worry about trivial details like that and carried on using it.

The chances are any wiring would be ok as it's generally in the void
between the inner and outer casings.

Because Mums old microwave hadn't actually been dumped I managed to
strip it down last night (well, pull the key components for the S&S's)
and now I'm thinking of putting it back together, just to see if it
still works. The only thing (apart from being able to correctly
re-connect the wiring) was the magnetron (the bit that generates the
microwaves) fell off the table and on to the concrete and I'm guessing
that's not the ideal way to treat such things?

We were taking Mum though her new Russell Hobbs pushbutton microwave
last night and I'm really not sure that it's going to be as 'easy' to
use as her old two knob jobby for her needs. Yes you can do two stage
cooking (defrost then cook) and set a timer to start it cooking at a
specific time but it seems to rely quite a bit on knowing the weights
of things and that means she's also got to have the scales handy.

Will she remember that 10% is the same as the 'Defrost' position on
her old one. Will she remember / work out how to set it to 10%?

We bought this model for her because we got it at a good price, it
seemed as large as her old one and had good reviews re it's cooking
(heating) ability. In trying to research the microwave it reminded me
why we still have our 30+ year old one and our old conventionally
vented tumble dryer and why buying such things can be like buying
laptops or shoes for someone else.

But she can't complain (not that she has or is likely to), we did
offer to take her round and look at a range so she could choose for
herself but she didn't want to, "I'll leave it up to you ...". ;-(

The problem is you can't really try these things in the shops.

Cheers, T i m

On Thursday, 26 May 2016 00:21:07 UTC+1, T i m wrote:
The worst example of this are those who actually throw away (as
opposed to give away or re-cycle even) perfectly good stuff, simply
because it doesn't match their new colour scheme.

It really annoys me to see perfectly good* furniture dumped outside when an hour the rain renders it useless, when the council and a local charity do free furniture uplift for resale in the recycling centre.

My neighbours don't even own a screwdriver and had no idea what to do with an electric cooker that didn't have a plug on it. They do drink quite a lot of buckfast though, and enjoy munchy boxes.

Owain


* Well, it would appeal to people who like interior design by Poundstretcher

On 26/05/16 09:20, wrote:
On Thursday, 26 May 2016 00:21:07 UTC+1, T i m wrote:
The worst example of this are those who actually throw away (as
opposed to give away or re-cycle even) perfectly good stuff, simply
because it doesn't match their new colour scheme.

It really annoys me to see perfectly good* furniture dumped outside when an hour the rain renders it useless, when the council and a local charity do free furniture uplift for resale in the recycling centre.

My neighbours don't even own a screwdriver and had no idea what to do with an electric cooker that didn't have a plug on it. They do drink quite a lot of buckfast though, and enjoy munchy boxes.

Owain


* Well, it would appeal to people who like interior design by Poundstretcher


I had an idea that instead of income tax, if we taxed *new* stuff, the
country would repair a huge amount more stuff than it does. And create
rather more worthwhile jobs than speed awareness course instructors..




--
"When a true genius appears in the world, you may know him by this sign,
that the dunces are all in confederacy against him."

Jonathan Swift.

The Natural Philosopher a écrit :
All Dysons should be dumped.
Britains own Apple. All fashion and form and **** all function.

Yesterday, I saw a local council truck, one of those with a metal cage
around the load, it was absolutely brim full of Dyson vacs. There must
have been hundreds of them. It just seemed odd that there were just
Dyson vacs in there.