i have a very interesting question about computer microwave ovens

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > YOSPOS > i have a very interesting question about computer microwave ovens

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LP0 ON FIRE: Jan 25, 2006; _{beep boop}

excuse me

i think i found a programming bug that seems apparent in just about all conventional microwaves driven by a microcontroller. after the timer runs to 0, the microwave seems to continue to run while beeping multiple times. the fan and lights might be just running and not actually creating microwaves to cook the food, but if this is true, why do i have the option to press the stop button and cancel all that nonsense? my theory is that it is actually continuing to cook the food during that duration which leads me to believe the duration of cooking time the user inputs ends up being inaccurate by several seconds

# ? Aug 3, 2014 11:19

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# ? Apr 23, 2024 13:25

EMILY BLUNTS: Jan 1, 2005

try this. type in 90 seconds and see what it does

# ? Aug 3, 2014 11:36

theadder: Dec 30, 2011

so wheres the interesting question op

# ? Aug 3, 2014 11:47

Dr. Honked: Jan 9, 2011; eat it you slaaaaaaag

disable the door interlock, put your head in there, and stick your tongue out. run the microwave for ten minutes. see if your tongue is still boiling while the beeps are going. then eat ten packs of mentos and drink two litres of coca cola as fast as you can, then set fire to yourself and jump out of the window. all your questions will be answered.

# ? Aug 3, 2014 13:43

LP0 ON FIRE: Jan 25, 2006; _{beep boop}

all microwaves are flawed and no one took notice until now (me)

Dr. Honked posted:

disable the door interlock, put your head in there, and stick your tongue out. run the microwave for ten minutes. see if your tongue is still boiling while the beeps are going. then eat ten packs of mentos and drink two litres of coca cola as fast as you can, then set fire to yourself and jump out of the window. all your questions will be answered.

that doesn't prove anything about my theory!

# ? Aug 3, 2014 16:30

minivanmegafun: Jul 27, 2004

op read this and get back to us

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

# ? Aug 3, 2014 16:31

minivanmegafun: Jul 27, 2004

Cross section diagram of typical magnetron

The really extraordinary ASCII art below represents (or is supposed to represent) a cross section of the 2M214 type magnetron (not to scale) through the center as viewed from the side.

code:

                                ________
                               |  ____  |
                               |_|    |_|  Antenna cap
                               / |____| \
                              |  | || |  | Antenna insulator
                              |  | || |  |
                      xxxxxxxx|__| || |__|xxxxxxxx RF sealing gasket
          ____________________|    ||    |____________________ 
         |        |       (5)||    ||    ||       (5)|        |
         |        |   Top    ||    ||    ||   Top    |        |
         |        |  Magnet  ||    ||    ||  Magnet  |        | Outer case
         |        |__________||    ||    ||__________|        |
         |              ______|     \\   |______              |
         |             /____    (7)   \\    ____\             |
         |____________||    \__  ______ \\ /    ||____________|
         |            ||_______ |__  __| _\\ ___||            |
         |____________||       | o || o |  ||(4)||____________|
         |            ||       | o || o |       ||        (6) | Heat sink fins
         |____________|| Vane  | o || o |  Vane ||____________|
         |            || (3)   | o || o |  (3)  ||            |
         |____________||       | o || o |       ||____________| o: Filament
         |            ||_______|(1)|| o |_______||            |    helix
         |____________||     __ |_||||_| __     ||____________|
         |            ||____/   || ||      \____||<-- (2)     |
         |             \______   \\ \\    ______/             |
         |         __________ |  ||  ||  | __________         |
         |        |       (5)||  ||  ||  ||       (5)|        |
         |        |  Bottom  ||  ||  ||  ||  Bottom  |        |
         |        |  Magnet  ||  ||  ||  ||  Magnet  |        |
         |________|__________||  ||  ||  ||__________|________|
             |                |__||__||__|                |
             |                 | ||  || |  Filament       |
             |                 | ||  || |  insulator      |
             |   (RF chokes    |_||__||_|                 |
             |    not shown)     ||  ||  Filament/cathode |
             |                   ||  ||  connections      |
             |____________________________________________|

# ? Aug 3, 2014 16:32

minivanmegafun: Jul 27, 2004

Microwave generator circuit diagram

Nearly all microwave ovens use basically the same design for the microwave generator. This has resulted in a relatively simple system manufactured at low cost.
The typical circuit is shown below. This is the sort of diagram you are likely to find pasted inside the metal cover. Only the power circuits are likely included (not the controller unless it is a simple motor driven timer) but since most problems will be in the microwave generator, this schematic may be all you need.

code:

                                      || +------------------------+
                                      ||( 3.3 VAC, 10 A, typical  |
                        TP  Relay or  || +------------+------+FA F| Magnetron
       _    I       I   __    Triac   ||              |    +-|----|-+
   o--- _---/ --+---/ --  ----/ ----+ || +------||----+    | |_  _| |
                |                    )||( HV Cap      |    |   \/   |
  AC           I \ I=Interlock       )||(           __|__  |   ___  |
 Line           |  TP=Thermal Prot.  )||( 2,000 VAC _\_/_  +----|:--+
   o------------+-------------------+ ||( 0.5 A       | HV      |'--> Micro-
                                      ||( typical     | Diode   |      waves
       (Controller not shown)         || +------------+---------+
                                                     _|_ 
                                                      -  Chassis ground

# ? Aug 3, 2014 16:32

minivanmegafun: Jul 27, 2004

High frequency inverter type HV power supplies

While the vast majority of microwave ovens - perhaps every single one you will ever see - use minor variations on the tried and trusted half wave doubler circuit, a few models have been designed using solid state high frequency inverters - in many ways similar to the deflection/HV flyback power supply of a TV or monitor.
A typical circuit (from a Sharp microwave oven) uses full wave rectified but mostly unfiltered pulsating DC as the power to a large ferrite inverter transformer which sort of looks like a flyback on steroids. See High Voltage Inverter Power Supply from Sharp Microwave Oven. This means that the microwave output is pulsing at both 60 Hz and the frequency of the inverter!

code:


        Bridge Rectifier         Inverter Transformer            Magnetron
                                       o
  H o----+---|>|------+--------+-------+    +--------------------------+
        ~|            |+      _|_ Drive )::( Filament 1T #18           |
         +---|<|---+  |       ---   25T ):: +--------------+------+    |
 115 VAC           |  |        |    #12 )::   HV Cap       |    +-|----|-+
         +---|>|---|--+        +-------+ :: +-------||-----+    | |_  _| |
         |         |           |         ::(    .018 uF    |    |   \/   |
  N o----+---|<|---+   Drive |/ C        ::(    2,400 V  __|__  |   ___  |
        ~          |-    o---|   Chopper ::( HV          _\_/_  +----|:--+
 (Interlocks and   |         |\ E        ::( 250T          | HV      |'-->
  fuses/protectors |           |         ::( #26   Sense   | diode   | uWaves
  not shown)       +-----------+            +--+---/\/\----+---------+
                                             o  |    1.2   _|_
 (Except for filament, # turns estimated)       o H1        -  Chassis Ground

# ? Aug 3, 2014 16:33

Sweevo: Nov 8, 2007; i sometimes throw cables away

i mean straight into the bin without spending 10+ years in the box of might-come-in-handy-someday first

im a fucking monster

LP0 ON FIRE posted:

i think i found a programming bug that seems apparent in just about all conventional microwaves driven by a microcontroller. after the timer runs to 0, the microwave seems to continue to run while beeping multiple times.

mine doesn't :smug:

# ? Aug 3, 2014 16:55

LP0 ON FIRE: Jan 25, 2006; _{beep boop}

minivanmegafun those diagrams and explanations are cool but i think all the microwaves are doing is not ending the cook routine before the "Done beeping" routine, and for some reason all microwaves i've ever seen use this

Sweevo posted:

mine doesn't

i don't believe you. you must be misunderstanding. show me a video please

# ? Aug 3, 2014 17:23

LP0 ON FIRE: Jan 25, 2006; _{beep boop}

i checked out the panasonic website, and they had this for an answer:

http://eng.faq.panasonic.com/app/answers/detail/a_id/10680/~/my-microwave-seems-to-run-after-the-cooking-has-finished.

they are admitting it's flawed right there, because if i press the stop button, everything stops immediately. the cooling fan routine "to cool down the elements inside" never happens. so does this mean i'm causing potential damage to my microwave just by hitting the stop button and not waiting for the timer to finish?

# ? Aug 3, 2014 17:31

Dr. Honked: Jan 9, 2011; eat it you slaaaaaaag

# ? Aug 3, 2014 17:38

Valeyard: Mar 30, 2012; Grimey Drawer

Dr. Honked posted:

lol

# ? Aug 3, 2014 17:41

LP0 ON FIRE: Jan 25, 2006; _{beep boop}

yeah it's probably every day i use a microwave it reminds me of microwave's mom and how much i still wish she was mine

# ? Aug 3, 2014 17:41

Valeyard: Mar 30, 2012; Grimey Drawer

she could warm my meat up in 60 seconds :smugmrgw:

# ? Aug 3, 2014 18:07

Farecoal: Oct 15, 2011; There he go

idgi

# ? Aug 3, 2014 18:17

Dr. Honked: Jan 9, 2011; eat it you slaaaaaaag

Farecoal posted:

idgi

http://forums.somethingawful.com/dictionary.php?act=3&topicid=1955

# ? Aug 3, 2014 18:28

LP0 ON FIRE: Jan 25, 2006; _{beep boop}

Valeyard posted:

she could warm my meat up in 60 seconds

# ? Aug 3, 2014 18:33

Sweevo: Nov 8, 2007; i sometimes throw cables away

i mean straight into the bin without spending 10+ years in the box of might-come-in-handy-someday first

im a fucking monster

LP0 ON FIRE posted:

i don't believe you. you must be misunderstanding. show me a video please

look on my works, ye mighty, and despair

# ? Aug 3, 2014 18:45

LP0 ON FIRE: Jan 25, 2006; _{beep boop}

Sweevo posted:

look on my works, ye mighty, and despair

no. loving. way.

what kind of microwave is that??

edit: and question - did turning off the beep sound affect this?

# ? Aug 3, 2014 18:49

Sweevo: Nov 8, 2007; i sometimes throw cables away

i mean straight into the bin without spending 10+ years in the box of might-come-in-handy-someday first

im a fucking monster

the beeper is still on, it's just got very quiet over the years. the mic doesn't pick it up very well either for some reason which makes it sound even quieter

# ? Aug 3, 2014 19:00

LP0 ON FIRE: Jan 25, 2006; _{beep boop}

okay i think i hear it, it's that chirping sound

# ? Aug 3, 2014 19:05

lazydog: Apr 15, 2003

when i was little we had a microwave with a mechanical dial timer that made a satisfying "ding" when it was finished.

someone should bring back appliances with actual bells and whistles instead of piezoelectric buzzers

# ? Aug 3, 2014 19:35

computer toucher: Jan 8, 2012

mine does that too and I guess it's so that you don't forget you have food there.

# ? Aug 3, 2014 20:00

Nintendo Kid: Aug 4, 2011; by Smythe

i wish i had a nice big microwave with working popcorn autosensor thingy again

# ? Aug 3, 2014 20:03

echinopsis: Apr 13, 2004; by Fluffdaddy

microwaves suck but they have their uses from time to time

pro tip leave the food for a bit after (do this with most cooking but esp with a 'wave)

# ? Aug 3, 2014 20:08

Captain Cool: Oct 23, 2004; This is a song about messin' with people who've been messin' with you

lazydog posted:

when i was little we had a microwave with a mechanical dial timer that made a satisfying "ding" when it was finished.

someone should bring back appliances with actual bells and whistles instead of piezoelectric buzzers

most toaster ovens are like this

the problem is that if the thing is unplugged it will still wind and tick and ding like normal

# ? Aug 3, 2014 20:18

LP0 ON FIRE: Jan 25, 2006; _{beep boop}

echinopsis posted:

pro tip leave the food for a bit after (do this with most cooking but esp with a 'wave)

haha you're joking right? are you scared of microwave radiation or are you just saying this to have it cool off? remember, microwaves are non-ionizing

# ? Aug 3, 2014 21:12

Sweevo: Nov 8, 2007; i sometimes throw cables away

i mean straight into the bin without spending 10+ years in the box of might-come-in-handy-someday first

im a fucking monster

i've met grown adults who think microwaves are radioactive

# ? Aug 3, 2014 21:14

echinopsis: Apr 13, 2004; by Fluffdaddy

LP0 ON FIRE posted:

haha you're joking right? are you scared of microwave radiation or are you just saying this to have it cool off? remember, microwaves are non-ionizing

because microwaves heat food so fast they often heat just the outside or certain parts*, and leaving it allows the temperature through the food to come to equilibrium... unless you enjoy bites of your food that are both hot and cold at the same time

this happens with a traditional oven too but since food has often been in the oven for long-time the effect is very small compared to microwave

*often if you cook a food in a container than has better temperature conductivity than the food itself, the outside of the food will heat but the bowl will absorbe that heat from the food preferentially instead of the rest of the food so you end up with a hot bowl and cold food. another reason to let it rest

# ? Aug 3, 2014 21:18

MancXVI: Feb 14, 2002

microwaves

https://www.youtube.com/watch?v=g91xkISmp2g

# ? Aug 3, 2014 21:48

LP0 ON FIRE: Jan 25, 2006; _{beep boop}

echinopsis posted:

because microwaves heat food so fast they often heat just the outside or certain parts*, and leaving it allows the temperature through the food to come to equilibrium... unless you enjoy bites of your food that are both hot and cold at the same time

this happens with a traditional oven too but since food has often been in the oven for long-time the effect is very small compared to microwave

*often if you cook a food in a container than has better temperature conductivity than the food itself, the outside of the food will heat but the bowl will absorbe that heat from the food preferentially instead of the rest of the food so you end up with a hot bowl and cold food. another reason to let it rest

ah yes. good tips.

did you know contrary to previously thought, microwaves were proven to be the healthiest form of cooking, meaning it maintains nutrition in the food more than any other form of cooking

# ? Aug 3, 2014 22:12

Dr. Honked: Jan 9, 2011; eat it you slaaaaaaag

MancXVI posted:

microwaves

https://www.youtube.com/watch?v=g91xkISmp2g

yikes

# ? Aug 4, 2014 00:37

LP0 ON FIRE: Jan 25, 2006; _{beep boop}

geez where's their safety glasses?

# ? Aug 4, 2014 00:48

theadder: Dec 30, 2011

echinopsis posted:

pro tip leave the food for a bit after (do this with most cooking but esp with a 'wave)

yep

# ? Aug 4, 2014 01:40

lazydog: Apr 15, 2003

when i heat up things like chicken nuggets, after i microwave them, i stick them in the toaster oven for a minute to make them crispy

# ? Aug 4, 2014 02:01

A Wheezy Steampunk: Jul 16, 2006; High School Grads Eligible!

i don't even own a microwave :smug:

# ? Aug 4, 2014 02:10

A Wheezy Steampunk: Jul 16, 2006; High School Grads Eligible!

https://www.youtube.com/watch?v=ZDrgMLTZd60

# ? Aug 4, 2014 02:10

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# ? Apr 23, 2024 13:25

echinopsis: Apr 13, 2004; by Fluffdaddy

A Wheezy Steampunk posted:

i don't even own a microwave

I ised to keep ours in our garage so it hardly for used

thu are useful for heating things up. NEVER for cooking

LP0 ON FIRE posted:

ah yes. good tips.

did you know contrary to previously thought, microwaves were proven to be the healthiest form of cooking, meaning it maintains nutrition in the food more than any other form of cooking

yeah that might be true but on the other hand who cares make food delicious!!! yum yum

# ? Aug 4, 2014 02:13

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > YOSPOS > i have a very interesting question about computer microwave ovens

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