OT magnetron service life

[Johny B Good]

We recently purchased a new microwave oven from Sainsburys to replace
our 20 years plus old Toshiba ER-7700E which had developed an
intermittent display fault (requiring a slap on its side to resurrect
the display, implying a bad connector contact or dry joint).

Out of curiousity, I'd already googled for info on the durability of
microwave ovens and noted an oft quoted figure of 2,000 hours for the
magnetron. Since a conservative estimate of 15 minutes a day usage
over a 20 year period produced a figure of some 1,826 hours and I
suspect the microwave oven may be even older than 25 years, I thought
it only prudent to buy a cost effective replacement.

The model we bought was a Sainsbury's Stainless Steel 20 litre
"Special" with a rating of 800W reduced from 80 quid to 40 quid (with
another fiver knocked of the price by way of a good will gesture on
account we'd had to return it for an 'undamaged' replacement).

We chose this particular model on account of a recommendation by my
younger brother and SiL who had found it outperformed other more
expensive models that they'd had the misfortune to experience
(thankfully, with full refund policies, just a matter of
inconvenience).

The fact that it used a rotary control knob to dial the time into the
electronic controller in a very similar fashion to that ancient
Toshiba's fine example of ergonomic perfection and the Which magazine
user reports being almost universally positive was the final clincher.

Having finally established a replacement for the Toshiba a couple of
weeks ago, I've had the old microwave oven sat on my workbench with
the cover off so I could examine the controller board.

There didn't appear to be any sign of dry joints or capacitor rot so
it's quite possibly just a bad contact in one of the four or so plug
connectors to the board, each of which I reseated (several times).
This action may well have cured the intermittent display fault (I've
not seen any display problems with the few tests I've done since so it
looks promising).

However, the main reason as to why the old oven has spent so much
time perched on my workbench is that I've been wanting to run an
'efficiency test' which requires a suitable thermometer (ideally a
calibrated standard glass/liquid lab thermometer covering the range
-10 deg to 110 deg C). The half litre plastic jug of water is the easy
requirement to fulfil.

Today, after looking at suitable (but overpriced) alternatives in the
gardening accessories dept of our local Wilkinsons store, I finally
decided to 'wrench' our existing outdoor thermometer (which had been
bought it in Home Bargain last summer for the princely sum of 89
pence) off the masonary nail I'd used to attach it to the wall. It
turned out that I was able to riggle the masonary nail out of the
cement mortar joint without damaging the thermometer (score one for me
and nil to the retail trade practice of 'Seasonal Stocking').

Having finally collected my 'Test Equipment' together, the first item
I tested was the brand new "800W" oven. A 500ml jug of cold water was
heated up by 31 deg C with 120 seconds run time at full power. Using
the 4.18 joules per calorie approximation as my conversion factor, I
calculated an effective microwave power level of 540W. Strangely on
the low side for an oven with a specified 750 to 800W cooking power.

When it came to running the exact same test with the old oven (a 650W
rated oven according to the surpisingly large numbers of this model
still being advertised for private sale - we lost sight of the manual
many years ago so I was never quite sure of this and the model number
contains no real clue), the temperature rise was 30 deg C which, using
the same calculation, equates to a heating power of 522W, a mere
3.333% reduction compared to the new 750/800W microwave.

This rather begs the question, should I re-instate the Toshiba and
set the Sainsbury Special to one side as a spare or retire the old
oven permanently. For myself, it's a "No Brainer" since the Toshiba
controls are far and away the more 'advanced' with the additional
feature that the cancel button, unlike the SS, also acts as a silencer
for the "Cooking Completed" beeps (just 3 rather than the more
annoying 5 of the SS).

The one thing I _am_ mindful of is the possibility of reduced cathode
emission causing 'modeing' where the heating effect may be reduced
with high fat/low water content foodstuffs but with a 20 years plus
old 650W rated oven only being a mere 3.33% shy of the performance of
a brand new 750W oven, I'm left wondering whether any such
deterioration has taken place at all.

Like most such sources of "Expert Opinion" to be found via a google
search, I get the impression that most so called 'experts' are either
idiots or shills pushing a party line, in this case, one intended to
promote the sales of new, inferior, product.

IOW, does anyone here know if the "2,000 hour" figure that seems to
be parroted throughout the relevent fora have any basis in fact?
--
Regards, J B Good

[Graham.]

If you Google hard enough you will find that 600 odd watt ovens all
got upgraded overnight to 800 odd watt because the means of
calculating oven power changed. Think RMS vs Music Power ;-)

A question for you.
Are you saying that Sainsbury's sell an "own brand" microwave with a
stainless steel cooking cavity? I most have missed that when I was
looking.



--
Graham.

%Profound_observation%

[Tim+]

Johny B Good <johnny...@invalid.ntlworld.com> wrote:

>

> The fact that it used a rotary control knob to dial the time into the
> electronic controller in a very similar fashion to that ancient
> Toshiba's fine example of ergonomic perfection and the Which magazine
> user reports being almost universally positive was the final clincher.
>

But does it go "ding"?

A very important attribute of any "proper" microwave. ;-)

Tim

[Johny B Good]

Not 'ding', 5 (that's FIVE!) beeps when the countdown reaches zero.
The only way to cancel that unnecessarily long series of beeps is to
pre-empt them by cancelling before it reaches zero.

If you're into your Chinese cuisine, I'm afraid "Chicken Ding" is off
the menu.

[Graham.]

On Sun, 01 Dec 2013 23:48:47 +0000, Johny B Good

<johnny...@invalid.ntlworld.com> wrote:

>On Sun, 1 Dec 2013 20:39:26 +0000, Tim+
><timdow...@nospampleaseyahoo.co.uk> wrote:
>
>>Johny B Good <johnny...@invalid.ntlworld.com> wrote:
>>
>>>
>>> The fact that it used a rotary control knob to dial the time into the
>>> electronic controller in a very similar fashion to that ancient
>>> Toshiba's fine example of ergonomic perfection and the Which magazine
>>> user reports being almost universally positive was the final clincher.
>>>
>>
>>But does it go "ding"?
>>
>>A very important attribute of any "proper" microwave. ;-)
>>
>
> Not 'ding', 5 (that's FIVE!) beeps when the countdown reaches zero.
>The only way to cancel that unnecessarily long series of beeps is to
>pre-empt them by cancelling before it reaches zero.
>
> If you're into your Chinese cuisine, I'm afraid "Chicken Ding" is off
>the menu.

Is this Sainsbury's oven badged "Russell Hobbs" by any chance?

On the subject of your power tests, I use one of those cheap
indoor/outdoor digital thermometers from Lidl/Aldi type shops.
External temperature probe that can be submerged, and it has a
resolution of half a degree c

Even if the absolute accuracy is questionable, you are only interested
in delta T, and the response time is quite good.

--
Graham.

%Profound_observation%

[Johny B Good]

On Sun, 01 Dec 2013 20:24:00 +0000, Graham. <m...@privacy.net> wrote:

====snip====

>
>If you Google hard enough you will find that 600 odd watt ovens all
>got upgraded overnight to 800 odd watt because the means of
>calculating oven power changed. Think RMS vs Music Power ;-)
>
>A question for you.
>Are you saying that Sainsbury's sell an "own brand" microwave with a
>stainless steel cooking cavity? I most have missed that when I was
>looking.

I don't think they claimed the cavity was stainless steel, just that
the exterior finish was stainless steel (which still retains a
significant amount of paramagnetiism).

Try as I might, I couldn't find a model number, nor for that matter,
any user guide downloads. I think it was simply described as a
Sainsburys 800W 20 litre stainless steel microwave oven.

[Graham.]

Ah right.
SS interior was the most important atribute when I was looking. I came
across some that said stanless steel in the description but you needed
to see the machine and open the door to check.

--
Graham.

%Profound_observation%

[Johny B Good]

I used a cheap garden thermometer bought in the summertime from our
local Home Bargain store for the princely sum of, afaicr, 89pence.
It's the classic liquid in glass bulb capilary type with a max temp of
50 deg C (I can't recall what the minimum temp was - possibly -20 deg
C). The upper temperature limit was more than sufficient for this
test.

Usually the main problem with such cheap thermometers (including
electronic weather station types) is their calibration. They can quite
easily be off by a couple of degrees. However, as you say, this isn't
too important since we're only interest in the delta T. What's more,
in my case, even if the error varies with temperature, it still
allowed me to compare the performance between the two ovens which
confirmed my suspicion that there was very little to choose between
the two.

I'll swap the ovens around when I can avoid interference from the
XYL. If nothing else, I'm curious as to whether or not my reseating
the connectors has cleared the intermittent display fault (the only
problem that prompted the purchase of the "Sainsburys Special" in the
first place).

[Jeff Layman]

On 01/12/2013 18:59, Johny B Good wrote:
> We recently purchased a new microwave oven from Sainsburys to replace
> our 20 years plus old Toshiba ER-7700E which had developed an
> intermittent display fault (requiring a slap on its side to resurrect
> the display, implying a bad connector contact or dry joint).

(snip)

> IOW, does anyone here know if the "2,000 hour" figure that seems to
> be parroted throughout the relevent fora have any basis in fact?

We were given a present of a Hinari 800w microwave oven in 1994. It
worked very well, but at a critical time in 2001 started sparking inside
(it was just a small bit of carbonised food, but I didn't know that at
the time). It was replaced with a 900w Panasonic. I was certain it
didn't have the power output of the Hinari, IIRC, some weeks later I
measured it in a similar way to you, at about 725w. By this time I had
cleaned the Hinari and given it to my daughter, so couldn't measure its
power output.

The Hinari continues to be used, and works perfectly even though it will
be 20 years old next June.

--

Jeff

[Brian Gaff]

I think, answering in true politician format, that you are in fact asking
the wrong question here. Most microwaves have a turntable due to the uneven
nature of the power of heating in different areas due to standing waves
etc, So unless you can actually be sure that your arbitrary placement of the
heatable jug etc, is always going to get the best efficiency, you really
cannot tell what is going on in any realistic way. Food does vary in
conductivity of heat of course so always, the way anything behaves in a
given machine will be mostly trial and error.
Also are you sure the actual power quoted is generated power? It might be
input power and efficiency does vary of course.
As for the original question, well, unless there is some catastrophic
failure caused by a fault in the high voltage feed or a flash over
Magnetrons last for ages. Early machines did have dire warnings about not
having stuff in the machine and definitely no metal etc, to stop the
standing waves damaging the machine, but I notice from the way mine behaves
if you do daft things, it just switches off the power and bleeps or pulses
the power to save the magnetron.
If you like watching microwave abuse, plenty of that on the web. Myth
busters and Brainiac to name but two.

I think I'd use any microwave I was used to, but it does pay to use the
other one from time to time to stop things like capacitors fading with age.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Johny B Good" <johnny...@invalid.ntlworld.com> wrote in message
news:svpm991vuegu1lak8...@4ax.com...

[Paul Ratcliffe]

On Mon, 02 Dec 2013 08:12:01 +0000, Jeff Layman <JMLa...@invalid.invalid>
wrote:

> The Hinari continues to be used, and works perfectly even though it will
> be 20 years old next June.

Mine is 22 years old and still going strong.
My mum's is 29 or 30 (can't quite remember) and suffers from slightly
reduced power output.
My brother's went to the tip after it started turning itself on at
random. It was perhaps 12-15 years old (can't really remember).
All are/were slightly different models of Panasonic.

[Paul Ratcliffe]

On Sun, 01 Dec 2013 23:48:47 +0000, Johny B Good
<johnny...@invalid.ntlworld.com> wrote:

> Not 'ding', 5 (that's FIVE!) beeps when the countdown reaches zero.
> The only way to cancel that unnecessarily long series of beeps is to
> pre-empt them by cancelling before it reaches zero.

I always want to put a 6th, longer, one on the end.

[Mark Carver]

On 02/12/2013 11:56, Paul Ratcliffe wrote:
> On Mon, 02 Dec 2013 08:12:01 +0000, Jeff Layman <JMLa...@invalid.invalid>
> wrote:
>
>> The Hinari continues to be used, and works perfectly even though it will
>> be 20 years old next June.
>
> Mine is 22 years old and still going strong.
> My mum's is 29 or 30 (can't quite remember) and suffers from slightly
> reduced power output.

Yes, my parents one, a Belling bought in 1978 lasted over thirty years,
it died in 2010


--
Mark
Please replace invalid and invalid with gmx and net to reply.

[Graham.]

On Mon, 02 Dec 2013 12:18:47 +0000, Mark Carver
<mark....@invalid.invalid> wrote:

>On 02/12/2013 11:56, Paul Ratcliffe wrote:
>> On Mon, 02 Dec 2013 08:12:01 +0000, Jeff Layman <JMLa...@invalid.invalid>
>> wrote:
>>
>>> The Hinari continues to be used, and works perfectly even though it will
>>> be 20 years old next June.
>>
>> Mine is 22 years old and still going strong.
>> My mum's is 29 or 30 (can't quite remember) and suffers from slightly
>> reduced power output.
>
>Yes, my parents one, a Belling bought in 1978 lasted over thirty years,
>it died in 2010

Here is the one we had for about 25 years.

http://www.photomemorabilia.co.uk/Photopia/Plustronics_Cats/tn_1982_microwave_frnt.jpg

For some reason it was cheaper than others that had simple
electromechanical timers, so the choice was a no brainer. It even had
a temperature probe that plugged into a socket in the oven, not that I
ever remember using it.

It was still working when it was retired in favour of a smaller one,
even the thing that most concerned me, the membrane keypad, was still
perfect both esthetically and operationally.



--
Graham.

%Profound_observation%

[Johny B Good]

Yes, it's a tempting thought, isn't it? However, if I was going to go
to the trouble of 'patching' the firmware, that _wouldn't_ be my
priority. :-)

[Johny B Good]

On Mon, 2 Dec 2013 10:02:07 -0000, "Brian Gaff"
<Bri...@blueyonder.co.uk> wrote:

>I think, answering in true politician format, that you are in fact asking
>the wrong question here. Most microwaves have a turntable due to the uneven
>nature of the power of heating in different areas due to standing waves
>etc, So unless you can actually be sure that your arbitrary placement of the
>heatable jug etc, is always going to get the best efficiency, you really
>cannot tell what is going on in any realistic way. Food does vary in
>conductivity of heat of course so always, the way anything behaves in a
>given machine will be mostly trial and error.

That issue of uneven heating due to standing waves only really
applies to solid foodstuff. With a jug of water, it's not really an
issue unless you're planning on bringing it close to boiling point
temperature.

The Toshiba also includes a 'stirrer' driven, rather neatly by the
exhaust flow of the magnetron cooling air, as well as a turntable.

>Also are you sure the actual power quoted is generated power? It might be
>input power and efficiency does vary of course.

The input power isn't quoted as such, the rating plate simply states
"240v (_that_ must date it!) at 5.6A which is 1344VA. The actual input
power measured 1250W on the test.

I've currently got a watt meter in line with the power feed to the
new oven and noticed a reading of 1370W whilst heating a bowl of milk
to dump a portion of 'shreddies' into for my 'breakfast' early this
PM.

I suppose I aught to check this using a half litre of water in the
same plastic measuring jug used for the original tests to get a more
useful comparison. BTW, it was this practice of heating a bowl of milk
for my breakfast cereal that led me to suspect that the new oven
wasn't any better than the old one since I found myself having to use
the same 100 seconds heating time to heat said milk to a similar
temperature.

> As for the original question, well, unless there is some catastrophic
>failure caused by a fault in the high voltage feed or a flash over
>Magnetrons last for ages. Early machines did have dire warnings about not
>having stuff in the machine and definitely no metal etc, to stop the
>standing waves damaging the machine, but I notice from the way mine behaves
>if you do daft things, it just switches off the power and bleeps or pulses
>the power to save the magnetron.

Yes, the power has to go somewhere, it can't build up indefinitely in
the system. The standing wave voltages will rise dramatically and the
surface currents in the cavity/waveguide/magnetron anode walls will
likewise build up increasing I squared R losses which can be tolerated
in the cavity and waveguide but far less so in the magnetron.

Undoubtedly, the output power of the magnetron will be reduced (which
aught to show as a reduced mains input power consumption - another
test to do) but not so much as to save the magnetron eventually
succumbing to the ill effects of the extra dissipation involved when
run under 'no load' conditions.

> If you like watching microwave abuse, plenty of that on the web. Myth
>busters and Brainiac to name but two.

Oh yes, I've watched many such 'interesting microwave experiments' on
youtube over the years. :-)

>
>I think I'd use any microwave I was used to, but it does pay to use the
>other one from time to time to stop things like capacitors fading with age.
> Brian

Personally, I'd rather keep the new one in reserve rather than put up
with the unnecessary pain of switching between a well implemented
control algorithm and an ill-thought out one.

[Graham.]

On Mon, 02 Dec 2013 17:15:44 +0000, Johny B Good

<johnny...@invalid.ntlworld.com> wrote:

>On Mon, 02 Dec 2013 11:59:08 GMT, Paul Ratcliffe
><ab...@orac12.clara34.co56.uk78> wrote:
>
>>On Sun, 01 Dec 2013 23:48:47 +0000, Johny B Good
>><johnny...@invalid.ntlworld.com> wrote:
>>
>>> Not 'ding', 5 (that's FIVE!) beeps when the countdown reaches zero.
>>> The only way to cancel that unnecessarily long series of beeps is to
>>> pre-empt them by cancelling before it reaches zero.
>>
>>I always want to put a 6th, longer, one on the end.
>
> Yes, it's a tempting thought, isn't it? However, if I was going to go
>to the trouble of 'patching' the firmware, that _wouldn't_ be my
>priority. :-)

I'd need it to be proceeded by a polyphonic rendition of Lillibolero.
Makes you proud to be Irish... er I mean British.

--
Graham.

%Profound_observation%

[bilou]

"Johny B Good" <johnny...@invalid.ntlworld.com> wrote in message

news:2ggp99t211ekrp8pm...@4ax.com...

> That issue of uneven heating due to standing waves only really
> applies to solid foodstuff. With a jug of water, it's not really an
> issue unless you're planning on bringing it close to boiling point
> temperature.

> snip...

> Personally, I'd rather keep the new one in reserve rather than put up
> with the unnecessary pain of switching between a well implemented
> control algorithm and an ill-thought out one.
> --

Nice OT discussion :-)
I totally agree that with a bowl of water position is not important.
It can be easily checked by repeating the measurement with various
positions.
A point that could induce errors is heating tlme of the magnetron.
To minimise its effect it is important to avoid too short tests.
5 minutes seems a minimum.
I would also use the new one during its waranty period.

[ne...@address.invalid]

On Sun, 01 Dec 2013 18:59:20 +0000, Johny B Good
<johnny...@invalid.ntlworld.com> wrote:

Haven't read the thread but this may be of interest..

http://www.dailymail.co.uk/news/article-2512024/Electrician-died-fixing-faulty-microwave-Marks--Spencer.html

[Johny B Good]

Yes, this latter point is worth considering. I must admit that,
despite the 'annoyance factor', I suppose we owe it to Sainsburys to
'properly' test their warranty, if only for a few months to reveal any
design/manufacturing deficiencies. However, I do want to run the old
one for a week or two to verify whether reseating the connectors has
cleared the intermittent display fault.

With regard to the cathode warm up time on the magnetron, the Toshiba
oven seems to require some 5 or 6 seconds after startup before it's up
to power (which rather spoils the cooking time accuracy for time
settings below 30 seconds - and makes a mockery of the 10 second time
setting).

What the cathode heat up time does to the 5 second minimum time
setting that's possible with the new Sainsburys one must be to
effectively reduce it to no more than 1 or 2 second's worth (the
countdown starts immediately after pressing the start button - there's
no obvious pause).

In either case, a 2 minute test run will be sufficiently accurate
enough for my purpose. If anything, I suspect the comparitive test
will favour the new oven over the old (the new one seems to need less
heater warmup time than the old).

I suppose I could set a 130 second time and cancel when it reaches
the 5 seconds remaining point in the Toshiba's case and similarly with
the new oven, cancelling it with 8 seconds to go in order to take some
account of this 'dead time' in the cycle.

I won't bother now with repeating the tests since I've arleady nailed
the thermometer back onto the wall. With regard to trying different
positions of the jug of water, I'd already done that by placing it
slightly offcentre on the turntable (something I've always done from
the off). I did read this piece of advice very recently either in the
user guide or, more likely, in an internet article on the subject of
cooking with microwave ovens. It was nice to see my thinking on this
matter of placement being validated elsewhere. :-)

[Johny B Good]

Interesting, it looks like he died from a good old fashioned electric
shock from mains voltage rather the -4.5KV EHT to the magnetron
cathode/heater connections if the description "an uninsulated
controller to a magnetron" has _any_ basis in fact. To me, the word
'controller' in this context means a relay operated switch carrying
mains voltage to the 2KV step up transformer or inverter used to power
the magnetron and its cathode heater circuit.

Since they weren't able to resuscitate him, I think it more likely to
be inaccurate reporting of the fact that he was electrocuted by the
EHT supply. It's this phrase in the article "finding him dead on the
floor" after immediately coming to his aid that worries me.

You'd think a large store would have an emergency defibrillator to
hand or else, failing that particular luxury (item), at least one
person capable of applying CPR until the paramedics arrive on the
scene.

Being rather leery of anything that's mains powered, let alone one
with a -4.5KV EHT supply capable of supplying nearly half an amp, I
stand well clear when operating the front panel user controls (and
make damn sure the thing is unplugged from the mains at all other
times whilst the cover is removed).

Even when the oven is unplugged from the mains, the EHT capacitor can
still retain a considerable charge if there's no built in bleed
resistor or said resistor has failed open circuit. There could still
be 1 to 2 KV lurking about on a capacitor measured in microFarads
rather than the few hundred picoFarads of that Leyden Jar affair that
those in the TV trade would more usually describe as the picture tube
(or valve).

A shock from the stored charge on a colour picture tube is but a
playful tickle compared to that which awaits the unwary would be
microwave oven 'tinkerer'. Even testing for the presence of stored
charge on that capacitor after unplugging from the mains supply is
problematical. For a start you need meter probes rated to at least 3KV
(there could be as much as 2.8KV due to heater failure of the
magnetron and an open circuit (or absence of) safety bleeder resistor.

Even so, you would be well advised to clip the positive test lead to
chassis ground before, single handedly, applying the negative test
probe to the heater/cathode terminals. I have to admit, this was one
test I didn't feel the need to make. I feel that life's short enough
already as it is with all the 'regular' risks in the environment that
threaten life and limb.

[ne...@address.invalid]

On Tue, 03 Dec 2013 01:43:39 +0000, Johny B Good

I can't understand why he was called in to repair a microwave oven.
Even the minimum callout charge would probably have paid for a
replacement oven. Much quicker, easier and cheaper to pop next door to
Argos/Currys/whatever for a new one.

[Peter Duncanson]

The electrician worked for Millers Vanguard. Millers Vanguard has
contractual arrangements with its customers. Presumably M&S had a
contract with that company to do electrical work in that and other
stores. In that case the electrician would be the equivalent of an
in-house electrician. If an electrical appliance is faulty he would
investigate and decide whether a simple repair is possible or whether it
should be replaced.

In that sort of environment it can be important to have a qualified
person decide whether an appliance is faulty or not. There is always the
possibility of some junior manager dishonestly declaring an appliance to
be faulty, arranging a replacement and then helpfully removing the
"faulty" item which is then sold on or used happily for years in that
person's home.

Millers Vanguard Reactive Maintenance:
http://www.millersvanguard.co.uk/reactive-maintenance/

Contacting our 24/7 state-of-the-art National Service Response
Centre your call will be put through to a qualified Engineer who
will screen the call, enabling us to contact you directly for a
remote fix wherever possible.

If a remote fix cannot be achieved we will send out an Engineer
within your contractual Service Level Agreement from a 4-hour
response onwards. All our vans are constantly tracked in order that
we can select the closest engineer for the fastest service. What’s
more, if our Engineer’s call screening has identified a requirement
for parts that are not carried in our Field Engineers’ extensive van
stock these are dispatched for delivery before 8am the next day.

All Reactive Engineers carry a PDA unit which not only sends them
precise details of each job but also gives them instant access to
our vast technical library helping them to achieve an 85%+ first
time fix rate. Where a device cannot be fixed on site it can be
rapidly replaced with a ready-to-dispatch loan device from our
extensive warehouse asset stock.


--
Peter Duncanson
(in uk.tech.digital-tv)

[mike.j....@gmail.com]

I have a Toshiba ER-672 with a mechanical timer and a bell. Yes, it goes 'ding' and just once too. I've had it for 30 years and 7 months and in that time I've only had one failure, the globe. That was until yesterday when it started making a loud buzzing noise. Time to retire it and get a new one I thought. That was until I read copious on-line reviews complaining about the extremely poor quality and reliability of modern microwave ovens. I visited all 5 electrical stores in my area and looked at all available ovens which only supported the complaints I'd read on-line. Decided to see if I could resurrect my old Toshiba so I opened the cover and found that the high voltage diode was shorted. A new one is on order, they cost just $5 so I'm hopeful that will keep it going for a few more decades. Once it's working again I'll measure its heating capacity but I have no reason to think it is less than the 650w it was when new.

[Indy Jess John]

On 01/01/2015 04:04, mike.j....@gmail.com wrote:
> I have a Toshiba ER-672 with a mechanical timer and a bell. Yes, it goes 'ding' and just once too. I've had it for 30 years and 7 months and in that time I've only had one failure, the globe. That was until yesterday when it started making a loud buzzing noise. Time to retire it and get a new one I thought. That was until I read copious on-line reviews complaining about the extremely poor quality and reliability of modern microwave ovens.

My Mum bought one of the early Panasonic microwaves, also with
mechanical timer. She used it at least once every day.

It never went wrong. When she died, my sister gave it to a charity shop.

I don't think it was 30 years old, but it was certainly more than 20.
And you are right about the modern ones not lasting so long. I am using
the third I have bought since my Mum bought hers.

Jim

[Tim+]

Our old Toshiba from the early 80s is still going strong.

Tim

[NY]

"Indy Jess John" <jimw...@OMITblueyonder.co.uk> wrote in message
news:NN7pw.256216$Su5.1...@fx03.am4...

My mum's microwave (mechanical timer, bell - not sure what make) is still
going strong and it's at least 35 years old. I know this because she got it
while my grandpa was still alive (he died in 1978) and we had to be careful
not to operate it when he was nearby because he had a heart pacemaker.

[Brian Gaff]

Well, I've never had one go. Modern machines cut the power if the standing
waves get back to the Magnetron to protect the things guts.


Of course yours may not be that sophisticated.
The Microwaves generally though do seem to make a loud buzz assumedly this
is the transformer rattling at 50 hz. Nobody has made a switch mode supply
big enough and safe enough I'd suspect.

Brian

--
From the Sofa of Brian Gaff Reply address is active

<mike.j....@gmail.com> wrote in message
news:40437dc8-0f06-4dd0...@googlegroups.com...

[Brian Gaff]

The Philips one I had only died due to the door going rusty, it had a bottom
hinge, and fell off!

Brian

--
From the Sofa of Brian Gaff Reply address is active

"NY" <m...@privacy.net> wrote in message
news:TKadndQjNPBdjzjJ...@brightview.co.uk...

[Paul Ratcliffe]

My mother's is about 30 and mine is 23. Both Panasonic. Both work well.

Dunno what the relevance to digital TV is though.

[JohnT]

"Paul Ratcliffe" <ab...@orac12.clara34.co56.uk78> wrote in message
news:slrnmaaita...@news.pr.network...

None, because it is identified as OT
--
JohnT

[Bill Wright]

JohnT wrote:

>> My mother's is about 30 and mine is 23. Both Panasonic. Both work well.
>>
>> Dunno what the relevance to digital TV is though.
>
> None, because it is identified as OT

It when they don't get OT that you have to chuck them. And this damned
chair is driving me mad.

Bill

[Bill Wright]

Brian Gaff wrote:
> Well, I've never had one go. Modern machines cut the power if the standing
> waves get back to the Magnetron to protect the things guts.
>
>
> Of course yours may not be that sophisticated.
> The Microwaves generally though do seem to make a loud buzz assumedly this
> is the transformer rattling at 50 hz. Nobody has made a switch mode supply
> big enough and safe enough I'd suspect.
> Brian
>

I've got one my Dad got for £19.95 from Aldi or somesuch place. It works
OK but starts afresh if you merely close the door, even if you've taken
the grub out. That makes it flash lightning bolts inside, and it sets
fire to the shite on the sides and top (inside I mean, not the shite
stood on the machine.)

Anyway, this squeaky chair is driving me bananas.

Bill

[Vir Campestris]

On 01/01/2015 18:56, Bill Wright wrote:
>
> Anyway, this squeaky chair is driving me bananas.

try uk.d-i-y :)

Andy

[Bill Wright]

They just talk of oil. But the oil is in another room, and I would have
to stand up to get it. Then I would have to apply the oil to the chair.
There are limits you know.

Bill

[Norman Wells]

Bill Wright wrote:
> Vir Campestris wrote:
>> On 01/01/2015 18:56, Bill Wright wrote:
>>>
>>> Anyway, this squeaky chair is driving me bananas.
>>
>> try uk.d-i-y :)
>
> They just talk of oil. But the oil is in another room, and I would
> have to stand up to get it. Then I would have to apply the oil to the
> chair.

No you wouldn't. You see, the chair would have stopped squeaking by
then and the problem would have been solved.

[Bill Wright]

Genius!

Bill