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Home > Archive > Home Repair forum > April 2006 > microwave - no power
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microwave - no power
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| Charles Bishop 2006-04-17, 11:21 pm |
| About an hour after I last used my microwave, I tried to use it again and
there was no power - the display was dark and nothing I could do on the
front panel brought it back.
What is the likelihood that it's just a blown fuse, or something similar?
If so, how easy would this be to get at and repair? What are the odds that
it's deader than the dodo? If it's the microwave generator whatsit, would
that mean the display is dark?
It's a Sharp Carousel and is at least 4 years old.
I checked the outlet and no joy there-it has power.
--
charles
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| Art Todesco 2006-04-18, 12:21 am |
| I had a similar problem where we
inadvertantly fat fingered the time buttons
and programmed in lots of extra minutes.
The food way overheated and popped
a fuseable link above the top of the
oven ceiling. A trip to the local applience
parts place and a new "flame detector"
got it back on line. May not be your
problem, but it is something to check.
Charles Bishop wrote:
> About an hour after I last used my microwave, I tried to use it again and
> there was no power - the display was dark and nothing I could do on the
> front panel brought it back.
>
> What is the likelihood that it's just a blown fuse, or something similar?
> If so, how easy would this be to get at and repair? What are the odds that
> it's deader than the dodo? If it's the microwave generator whatsit, would
> that mean the display is dark?
>
> It's a Sharp Carousel and is at least 4 years old.
>
> I checked the outlet and no joy there-it has power.
>
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| Mark Lloyd 2006-04-18, 1:21 am |
| On Tue, 18 Apr 2006 01:28:54 GMT, ctbishop@earthlink.netttt (Charles
Bishop) wrote:
>About an hour after I last used my microwave, I tried to use it again and
>there was no power - the display was dark and nothing I could do on the
>front panel brought it back.
>
>What is the likelihood that it's just a blown fuse, or something similar?
>If so, how easy would this be to get at and repair? What are the odds that
>it's deader than the dodo? If it's the microwave generator whatsit, would
>that mean the display is dark?
>
>It's a Sharp Carousel and is at least 4 years old.
>
>I checked the outlet and no joy there-it has power.
15 years ago I had a microwave that failed like that. I took the cover
off, knowing there was almost nothing I could do to fix it. However,
what was wrong was one of the few things I could fix. A blown fuse. A
replacement was about 69 cents at Radio Shack.
I still use that microwave.
--
Mark Lloyd
http://notstupid.laughingsquid.com
"Democracy is two wolves and a lamb voting on what
to have for lunch. Liberty is a well armed lamb
contesting the vote." - Benjamin Franklin
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| Beachcomber 2006-04-18, 3:21 am |
|
>
>15 years ago I had a microwave that failed like that. I took the cover
>off, knowing there was almost nothing I could do to fix it. However,
>what was wrong was one of the few things I could fix. A blown fuse. A
>replacement was about 69 cents at Radio Shack.
>
>I still use that microwave.
>--
>Mark Lloyd
>http://notstupid.laughingsquid.com
>
>"Democracy is two wolves and a lamb voting on what
>to have for lunch. Liberty is a well armed lamb
>contesting the vote." - Benjamin Franklin
A fuse is likely. It's very typical for them to die of old age. You
need an exact replacement though in terms of type and amperage. This
fuse is part of the protection circuit that protects not only the
microwave oven, but you.
I just had one die (A Sharp 1000 watt model). For about 3 weeks, I
could smell something burning when I used the microwave. Then
suddenly no power...
The problem is that my fuse melted the fuseholder and the plastic
support underneath. It still could be fixed, but at $69.95 for a new
replacement oven... the price alone of not having to clean it did it
for me.
Fuses also blow when there is trouble with the interlock switches.
Anything that draws high current, such as air conditioners, microwave
ovens, etc. can be trouble for fuses.
Beachcomber
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| Charles Bishop 2006-04-18, 6:21 pm |
| In article <h2n842l9hu0utoude10isd4nj12vuetea7@4ax.com>, Mark Lloyd
<mlloyd@xmail.com10> wrote:
>On Tue, 18 Apr 2006 01:28:54 GMT, ctbishop@earthlink.netttt (Charles
>Bishop) wrote:
>
>
>15 years ago I had a microwave that failed like that. I took the cover
>off, knowing there was almost nothing I could do to fix it. However,
>what was wrong was one of the few things I could fix. A blown fuse. A
>replacement was about 69 cents at Radio Shack.
>
>I still use that microwave.
Cool. I looked at the back last night and there were warnings against
taking it off beacuse of high voltage. Also, the screws holding it on are
star screws - they say it's for my protection since the high voltages are
there.
Do micorwaves have any large capicators or capicatorlike that would hold a
high voltage if it had been unplugged for a while?
I'm going to at least take the cover off even if I have to junk it so my
sone and I can see what's inside one.
What is odd to me is that the last thing I did was to heat something for
11 seconds. I think it beeped at me to let me know it was done, then I
opened the door, took out the stuff and closed the door. Unfortunately I
didn't notice at the time whether the display was dark or lit. Assuming it
was, is it likely the microwave would have failed when it wasn't being
used? If not, i may just misremember the beep or what happened when I
opened or closed the door.
--
charles
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| Rich256 2006-04-18, 7:21 pm |
| Charles Bishop wrote:
> In article <h2n842l9hu0utoude10isd4nj12vuetea7@4ax.com>, Mark Lloyd
> <mlloyd@xmail.com10> wrote:
>
>
> Cool. I looked at the back last night and there were warnings against
> taking it off beacuse of high voltage. Also, the screws holding it on are
> star screws - they say it's for my protection since the high voltages are
> there.
>
> Do micorwaves have any large capicators or capicatorlike that would hold a
> high voltage if it had been unplugged for a while?
>
> I'm going to at least take the cover off even if I have to junk it so my
> sone and I can see what's inside one.
>
> What is odd to me is that the last thing I did was to heat something for
> 11 seconds. I think it beeped at me to let me know it was done, then I
> opened the door, took out the stuff and closed the door. Unfortunately I
> didn't notice at the time whether the display was dark or lit. Assuming it
> was, is it likely the microwave would have failed when it wasn't being
> used? If not, i may just misremember the beep or what happened when I
> opened or closed the door.
>
Yeah, there is a cap that might give you a pretty good bite. It might
be bled off but still a good idea to keep your fingers away. What I do
is attach a shorting wire to ground if I am going to be in that area.
I will bet on the fuse too.
Had one that was shorting like mad. Took off the cover and found a moth
in the waveguide.
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| Charles Bishop 2006-04-18, 9:21 pm |
| In article <ixd1g.20056$az4.15448@bgtnsc04-news.ops.worldnet.att.net>,
Rich256 <nospam@nospam.net> wrote:
>Charles Bishop wrote:
>
>Yeah, there is a cap that might give you a pretty good bite. It might
>be bled off but still a good idea to keep your fingers away. What I do
>is attach a shorting wire to ground if I am going to be in that area.
>
>I will bet on the fuse too.
Is it likely I'll recognize the fuse? A flashing neon sign: "Fuse"? or do
I have to look around. The likeliest place I'd think would be just after
the line cord comes in.
>
>Had one that was shorting like mad. Took off the cover and found a moth
>in the waveguide.
Did you put it in the daily log with "first instance of actual bug in a
microwave"?
--
cahrles
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| Rich256 2006-04-18, 11:21 pm |
| Charles Bishop wrote:
>
> Is it likely I'll recognize the fuse? A flashing neon sign: "Fuse"? or do
> I have to look around. The likeliest place I'd think would be just after
> the line cord comes in.
The ones I have seen are the normal Buss type and usually mounted in an
open area on the chassis. Usually it is a slow blow or thermal type.
Just did a bit of searching and found some URLs you might take a look at:
http://www.everist.org/special/mw_oven/
http://home.cvc.org/microwaves/how_work.htm
Another thought. Not likely problem, but are you certain that the
breaker to the oven has not tripped? It could be on a breaker by itself.
I just recalled fixing one of the first Armana ovens. It was one of
those with a chrome door similar to the front end of a '55 Buick.
The power line ran through a hollow ceramic resistor that had one of
those one shot, thermal overload relays like you find in coffee pots.
The resistor was in the power line to the magnetron. If the magnetron
drew too much current the resistor got hot and blew the switch.
I had to search around to find a replacement relay with the same
temperature rating. Replaced it and the oven worked for a few more years.
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| Beachcomber 2006-04-19, 7:21 am |
| On Wed, 19 Apr 2006 02:08:48 GMT, Rich256 <nospam@nospam.net> wrote:
>Charles Bishop wrote:
>
>The ones I have seen are the normal Buss type and usually mounted in an
>open area on the chassis. Usually it is a slow blow or thermal type.
>
>
>Just did a bit of searching and found some URLs you might take a look at:
>
>http://www.everist.org/special/mw_oven/
>
>http://home.cvc.org/microwaves/how_work.htm
>
>Another thought. Not likely problem, but are you certain that the
>breaker to the oven has not tripped? It could be on a breaker by itself.
>
>I just recalled fixing one of the first Armana ovens. It was one of
>those with a chrome door similar to the front end of a '55 Buick.
>
>The power line ran through a hollow ceramic resistor that had one of
>those one shot, thermal overload relays like you find in coffee pots.
>The resistor was in the power line to the magnetron. If the magnetron
>drew too much current the resistor got hot and blew the switch.
>
>
Over a period of time, the magnetron may draw more current as it ages.
This may or may not be enough to blow the fuse. According to most of
the websites I've seen, the main fuse is the most common problem, with
75% of the faults caused by aging, high resistance fuses, or trouble
with the door interlocks (microswitches).
The microswitches can arc over internally, if they frequently break
any substatial amount of current.
Incidently, on most ovens, one of the microswitches is the fail-safe
"idiot" interlock microswitch which causes a direct short across the
AC power leads, should the door not be closed and if the magnetron
relay actually is in the ON state.
Beachcomber
>I had to search around to find a replacement relay with the same
>temperature rating. Replaced it and the oven worked for a few more years.
| |
| Mark Lloyd 2006-04-19, 12:21 pm |
| On Wed, 19 Apr 2006 00:14:51 GMT, ctbishop@earthlink.netttt (Charles
Bishop) wrote:
>In article <ixd1g.20056$az4.15448@bgtnsc04-news.ops.worldnet.att.net>,
>Rich256 <nospam@nospam.net> wrote:
>
>
>Is it likely I'll recognize the fuse? A flashing neon sign: "Fuse"? or do
>I have to look around. The likeliest place I'd think would be just after
>the line cord comes in.
>
The one I replaced was a standard-size .25 by 1.25 inch cylindrical
fuse. Radio Shack called the replacement a "Microwave Oven Fuse". It
was rated 15A.
>
>Did you put it in the daily log with "first instance of actual bug in a
>microwave"?
--
Mark Lloyd
http://notstupid.laughingsquid.com
"Democracy is two wolves and a lamb voting on what
to have for lunch. Liberty is a well armed lamb
contesting the vote." - Benjamin Franklin
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