Microwave buzzing a vibrating

Samsung MW8490W, about 6.5 years old. Tried microwaving something
today, and the microwave just vibrates and buzzes. It's definately a
60Hz-based buzz. No arcing or odd smells. Everything appears OK
except the metal enclosure vibrates violently like there's a loose
transformer in there.
Oh, it won't heat water, and is drawing only about 350W from the outlet
when running (rear label says 1.5KW).

I can tell you everything you want to know about electronics (well,
almost), but microwaves are somewhat of a mystery to me.

Any ideas on what's wrong, or where to start?

(E-Mail Removed) writes:

> Samsung MW8490W, about 6.5 years old. Tried microwaving something
> today, and the microwave just vibrates and buzzes. It's definately a
> 60Hz-based buzz. No arcing or odd smells. Everything appears OK
> except the metal enclosure vibrates violently like there's a loose
> transformer in there.
> Oh, it won't heat water, and is drawing only about 350W from the outlet
> when running (rear label says 1.5KW).
>
> I can tell you everything you want to know about electronics (well,
> almost), but microwaves are somewhat of a mystery to me.
>
> Any ideas on what's wrong, or where to start?

Shorted high voltage diode or magnetron.

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

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
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Sam Goldwasser wrote:
> (E-Mail Removed) writes:
>
> > Samsung MW8490W, about 6.5 years old. Tried microwaving something
> > today, and the microwave just vibrates and buzzes. It's definately a
> > 60Hz-based buzz. No arcing or odd smells. Everything appears OK
> > except the metal enclosure vibrates violently like there's a loose
> > transformer in there.
> > Oh, it won't heat water, and is drawing only about 350W from the outlet
> > when running (rear label says 1.5KW).
> >
> > I can tell you everything you want to know about electronics (well,
> > almost), but microwaves are somewhat of a mystery to me.
> >
> > Any ideas on what's wrong, or where to start?
>
> Shorted high voltage diode or magnetron.
>
> --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
> Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
> +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
> | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html
>
> Important: Anything sent to the email address in the message header above is
> ignored unless my full name AND either lasers or electronics is included in the
> subject line. Or, you can contact me via the Feedback Form in the FAQs.

Any quick checks that can be made? Should the two terminals to the mag
have some low resistance? (I'm not sure what they connect to)

I'm also going to read up some more on how these things work.

Stay out of that thing. And if you could buy a new magnetron, it would
probably cost more than a new microwave.

Perce


On 02/26/06 06:48 pm (E-Mail Removed) wrote:

> Samsung MW8490W, about 6.5 years old. Tried microwaving something
> today, and the microwave just vibrates and buzzes. It's definately a
> 60Hz-based buzz. No arcing or odd smells. Everything appears OK
> except the metal enclosure vibrates violently like there's a loose
> transformer in there.
> Oh, it won't heat water, and is drawing only about 350W from the outlet
> when running (rear label says 1.5KW).
>
> I can tell you everything you want to know about electronics (well,
> almost), but microwaves are somewhat of a mystery to me.
>
> Any ideas on what's wrong, or where to start?
>

Stay out, why? I know there's a HV capacitor in there, and I know
electronics plenty good enough to know what not to do.

And yes, you're right. Magnetrons are expensive. However, I just
tracked it down to the diode. 0.040 V drop in both directions. Yeah,
it's shorted. Much cheaper than a new microwave.

Percival P. Cassidy wrote:
> Stay out of that thing. And if you could buy a new magnetron, it would
> probably cost more than a new microwave.
>
> Perce
>
>
> On 02/26/06 06:48 pm (E-Mail Removed) wrote:
>
> > Samsung MW8490W, about 6.5 years old. Tried microwaving something
> > today, and the microwave just vibrates and buzzes. It's definately a
> > 60Hz-based buzz. No arcing or odd smells. Everything appears OK
> > except the metal enclosure vibrates violently like there's a loose
> > transformer in there.
> > Oh, it won't heat water, and is drawing only about 350W from the outlet
> > when running (rear label says 1.5KW).
> >
> > I can tell you everything you want to know about electronics (well,
> > almost), but microwaves are somewhat of a mystery to me.
> >
> > Any ideas on what's wrong, or where to start?
> >

(E-Mail Removed) writes:

> Sam Goldwasser wrote:
> > (E-Mail Removed) writes:
> >
> > > Samsung MW8490W, about 6.5 years old. Tried microwaving something
> > > today, and the microwave just vibrates and buzzes. It's definately a
> > > 60Hz-based buzz. No arcing or odd smells. Everything appears OK
> > > except the metal enclosure vibrates violently like there's a loose
> > > transformer in there.
> > > Oh, it won't heat water, and is drawing only about 350W from the outlet
> > > when running (rear label says 1.5KW).
> > >
> > > I can tell you everything you want to know about electronics (well,
> > > almost), but microwaves are somewhat of a mystery to me.
> > >
> > > Any ideas on what's wrong, or where to start?
> >
> > Shorted high voltage diode or magnetron.
> >
> > --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
> > Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
> > +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
> > | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html
> >
> > Important: Anything sent to the email address in the message header above is
> > ignored unless my full name AND either lasers or electronics is included in the
> > subject line. Or, you can contact me via the Feedback Form in the FAQs.
>
> Any quick checks that can be made? Should the two terminals to the mag
> have some low resistance? (I'm not sure what they connect to)
>
> I'm also going to read up some more on how these things work.

First you MUST read up on the SAFETY issues. Even though this one appears
quite dead, you don't want to take chances.

Complete troubleshooting quide at the Web site, below.

With the unit unplugged, make sure the HV capacitor is discharged.

The two terminals on the magnetron are the filament and should be low
resistance, close to zero ohms. But they ahould read open to the chassis.

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

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

On 26 Feb 2006 16:35:21 -0800, (E-Mail Removed) wrote:

>
>Sam Goldwasser wrote:
>> (E-Mail Removed) writes:
>>
>> > Samsung MW8490W, about 6.5 years old. Tried microwaving something
>> > today, and the microwave just vibrates and buzzes. It's definately a
>> > 60Hz-based buzz. No arcing or odd smells. Everything appears OK
>> > except the metal enclosure vibrates violently like there's a loose
>> > transformer in there.
>> > Oh, it won't heat water, and is drawing only about 350W from the outlet
>> > when running (rear label says 1.5KW).
>> >
>> > I can tell you everything you want to know about electronics (well,
>> > almost), but microwaves are somewhat of a mystery to me.
>> >
>> > Any ideas on what's wrong, or where to start?
>>
>> Shorted high voltage diode or magnetron.
>>
>> --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
>> Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
>> +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
>> | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html
>>
>> Important: Anything sent to the email address in the message header above is
>> ignored unless my full name AND either lasers or electronics is included in the
>> subject line. Or, you can contact me via the Feedback Form in the FAQs.
>
>Any quick checks that can be made? Should the two terminals to the mag
>have some low resistance? (I'm not sure what they connect to)
>
>I'm also going to read up some more on how these things work.

The most important thing is to either not mess with the cage around
the microwave part, or to put it back EXACTLY the way you find it. At
first the Amana girl refused to send me a schematic (back when I
didn't realize how simple they are) because she thought I'd radiate
myself or my eyes to death. Apparently the metal side of the oven,
where the electronics are, is not enough to keep the waves inside.

You might want to get a microwave tester (10 dollars at Radio Shack)
to make sure there is no leakage. I calibrated mine by pulling the
door open a little but less than it took to have the oven turn off.
now that the ovens latch instead of just close, this might be harder
to do. The RS tester was calibrated fine to begin with afaict.


Remove NOPSAM to email me. Please let
me know if you have posted also.

On Sun, 26 Feb 2006 19:49:24 -0500, "Percival P. Cassidy"
<(E-Mail Removed)> wrote:

>Stay out of that thing. And if you could buy a new magnetron, it would
>probably cost more than a new microwave.

Don't know about that part but for Amana model #2, they wanted 700
dollars iirc for the transformer. After I whined (and pointed out
that no one would pay that price, they lowered it to the wholesale
price of 400 dollars. I don't think anyone will ever pay that price
either for an oven that had no special features, one power, and two
timers. And weighed so much it was hard to carry. All that was
good was that it was big and antique.

>Perce
>
>
>On 02/26/06 06:48 pm (E-Mail Removed) wrote:
>
>> Samsung MW8490W, about 6.5 years old. Tried microwaving something
>> today, and the microwave just vibrates and buzzes. It's definately a
>> 60Hz-based buzz. No arcing or odd smells. Everything appears OK
>> except the metal enclosure vibrates violently like there's a loose
>> transformer in there.
>> Oh, it won't heat water, and is drawing only about 350W from the outlet
>> when running (rear label says 1.5KW).
>>
>> I can tell you everything you want to know about electronics (well,
>> almost), but microwaves are somewhat of a mystery to me.
>>
>> Any ideas on what's wrong, or where to start?
>>


Remove NOPSAM to email me. Please let
me know if you have posted also.

mm wrote:
> On 26 Feb 2006 16:35:21 -0800, (E-Mail Removed) wrote:
>
> >
> >Sam Goldwasser wrote:
> >> (E-Mail Removed) writes:
> >>
> >> > Samsung MW8490W, about 6.5 years old. Tried microwaving something
> >> > today, and the microwave just vibrates and buzzes. It's definately a
> >> > 60Hz-based buzz. No arcing or odd smells. Everything appears OK
> >> > except the metal enclosure vibrates violently like there's a loose
> >> > transformer in there.
> >> > Oh, it won't heat water, and is drawing only about 350W from the outlet
> >> > when running (rear label says 1.5KW).
> >> >
> >> > I can tell you everything you want to know about electronics (well,
> >> > almost), but microwaves are somewhat of a mystery to me.
> >> >
> >> > Any ideas on what's wrong, or where to start?
> >>
> >> Shorted high voltage diode or magnetron.
> >>
> >> --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
> >> Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
> >> +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
> >> | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html
> >>
> >> Important: Anything sent to the email address in the message header above is
> >> ignored unless my full name AND either lasers or electronics is included in the
> >> subject line. Or, you can contact me via the Feedback Form in the FAQs.
> >
> >Any quick checks that can be made? Should the two terminals to the mag
> >have some low resistance? (I'm not sure what they connect to)
> >
> >I'm also going to read up some more on how these things work.
>
> The most important thing is to either not mess with the cage around
> the microwave part, or to put it back EXACTLY the way you find it. At
> first the Amana girl refused to send me a schematic (back when I
> didn't realize how simple they are) because she thought I'd radiate
> myself or my eyes to death. Apparently the metal side of the oven,
> where the electronics are, is not enough to keep the waves inside.
>
> You might want to get a microwave tester (10 dollars at Radio Shack)
> to make sure there is no leakage. I calibrated mine by pulling the
> door open a little but less than it took to have the oven turn off.
> now that the ovens latch instead of just close, this might be harder
> to do. The RS tester was calibrated fine to begin with afaict.
>
There's no cage around the microwave parts. It's in the open once the
outside shell has been removed. Nothing that I'm messing with here
looks real critical....just high voltage stuff. I'm not remove the mag
or anything.

(E-Mail Removed) writes:

> mm wrote:
> > On 26 Feb 2006 16:35:21 -0800, (E-Mail Removed) wrote:
> >
> > >
> > >Sam Goldwasser wrote:
> > >> (E-Mail Removed) writes:
> > >>
> > >> > Samsung MW8490W, about 6.5 years old. Tried microwaving something
> > >> > today, and the microwave just vibrates and buzzes. It's definately a
> > >> > 60Hz-based buzz. No arcing or odd smells. Everything appears OK
> > >> > except the metal enclosure vibrates violently like there's a loose
> > >> > transformer in there.
> > >> > Oh, it won't heat water, and is drawing only about 350W from the outlet
> > >> > when running (rear label says 1.5KW).
> > >> >
> > >> > I can tell you everything you want to know about electronics (well,
> > >> > almost), but microwaves are somewhat of a mystery to me.
> > >> >
> > >> > Any ideas on what's wrong, or where to start?
> > >>
> > >> Shorted high voltage diode or magnetron.
> > >>
> > >> --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
> > >> Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
> > >> +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
> > >> | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html
> > >>
> > >> Important: Anything sent to the email address in the message header above is
> > >> ignored unless my full name AND either lasers or electronics is included in the
> > >> subject line. Or, you can contact me via the Feedback Form in the FAQs.
> > >
> > >Any quick checks that can be made? Should the two terminals to the mag
> > >have some low resistance? (I'm not sure what they connect to)
> > >
> > >I'm also going to read up some more on how these things work.
> >
> > The most important thing is to either not mess with the cage around
> > the microwave part, or to put it back EXACTLY the way you find it. At
> > first the Amana girl refused to send me a schematic (back when I
> > didn't realize how simple they are) because she thought I'd radiate
> > myself or my eyes to death. Apparently the metal side of the oven,
> > where the electronics are, is not enough to keep the waves inside.
> >
> > You might want to get a microwave tester (10 dollars at Radio Shack)
> > to make sure there is no leakage. I calibrated mine by pulling the
> > door open a little but less than it took to have the oven turn off.
> > now that the ovens latch instead of just close, this might be harder
> > to do. The RS tester was calibrated fine to begin with afaict.
> >
> There's no cage around the microwave parts. It's in the open once the
> outside shell has been removed. Nothing that I'm messing with here
> looks real critical....just high voltage stuff. I'm not remove the mag
> or anything.

Right. Just try not to electrocute yourself in the process. If you don't
remove the magnetron, there is no critical seal you'll be affecting.

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

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.