On Sep 27, 4:09*pm, "Jon Danniken"
wrote:
Smitty Two wrote:
"Jon Danniken" wrote:
RF wrote:

I have discovered which oven not to buy but it's a bit late now.
The Model Number is: 72163252301 and, within the warranty, it made a
loud pop, then started a very loud buzzing and finally a smell of
burning plastic. I pulled the cord and brought it back to Sears. A
week later I had it back. That is just about a year ago and it now
has repeated.
This oven was very lightly used - not more than 20 mins/day.

If anyone has had this experience I'd appreciate the info. I also
note that the way it is assembled seems to make access more
difficult.

The way it is assembled is specificallly designed to make access
difficult. There is a power supply inside of that unit capable of
producing 4000 volts at a half an amp, which is guaranteed to kill
you.

As if that wasn't enough, the capacitor can retain sufficient enough
energy to cause a ventricular fibrillation long after the unit has
been turned off and unplugged.

Microwave ovens are rather simple devices, but unless you have the
specialized know-how in dealing with them, your life isn't worth it.

Fair and acceptable warnings to the complete idiot, but I believe
you're lapsing into hysterical hyperbole. Electricity is *not*
"guaranteed to kill you." It's only theoretically possible that you
could die from opening up a microwave to fix it. If you do
accidentally touch the wrong thing, it'll give you a shock, which
will remind you which part not to touch.

Most of those theoretically dangerous parts are hidden away in
secondary cages anyway. You can easily open up a microwave and fix it
without having a panic attack.

Well "Smitty", I don't think your perspective of high voltage/high current
appliances is a very practical one. *Beyond that, suggesting that the
innards of a microwave are anything less than lethal is beyond negligent,
and I'd say foolhardy as well.

Jon- Hide quoted text -

- Show quoted text -

I agree with Jon. The innards of a microwave CAN be lethal. That
doesn't mean any more than standing under car on a lift WILL be
lethal!
BTW I am a retired electronics and radio transmitter technician and
manager!
But it is very much the sense and capability of the d-i-yer that comes
into play. e.g.
I have one neighbour about whom every one shudders when he even looks
at electrcity, no matter how often you try to teach him. He's the kind
that says "Well can I put a screwdriver between there and chassis. My
brother says that will test the high voltage !!!!!". He is dangerous
with any voltage over 12 volts and he doesn't even understand that
unless he can clearly see a broken off or corroded wire on his truck!
Recently an acquaintance asked us to 'look at' his favourite
microwave. He'd opened it and couldn't find the problem. He felt it
could be the control board!!!!!
My son, also a technician, and I fixed it in about 15 minutes on the
kitchen table; a bad door micro-switch! The control board and the hi-
voltage and magnetron circuit worked fine once we replaced the
defective micro-switch (I have a jar of used ones salvaged from old
m.waves). While working on it we defeated the hi voltage to the
magnetron. For safety.
When the owner had reassembled his m.wave he had not put the cover
back on correctly and there was a potential leak on the right hand
edge very close to the door opener and close to where one would put a
hand to program or switch off! The 'edges' of the cover and the case
were improperly meshed ............... Strewth; do wish people
wouldn't touch stuff they don't understand!
For example I know nothing about automatic transmissions so I would
not 'go at' one. I'm also a very poor plasterer, so hands off.
Everyone having fun? Within their capabilities.

I'm reporting you to SPCEP, or Society for Prevention of
Cruelty to Exclaimation Points.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"stan" wrote in message
...


I agree with Jon. The innards of a microwave CAN be lethal.
That
doesn't mean any more than standing under car on a lift WILL
be
lethal!
BTW I am a retired electronics and radio transmitter
technician and
manager!
But it is very much the sense and capability of the d-i-yer
that comes
into play. e.g.
I have one neighbour about whom every one shudders when he
even looks
at electrcity, no matter how often you try to teach him.
He's the kind
that says "Well can I put a screwdriver between there and
chassis. My
brother says that will test the high voltage !!!!!". He is
dangerous
with any voltage over 12 volts and he doesn't even
understand that
unless he can clearly see a broken off or corroded wire on
his truck!
Recently an acquaintance asked us to 'look at' his favourite
microwave. He'd opened it and couldn't find the problem. He
felt it
could be the control board!!!!!
My son, also a technician, and I fixed it in about 15
minutes on the
kitchen table; a bad door micro-switch! The control board
and the hi-
voltage and magnetron circuit worked fine once we replaced
the
defective micro-switch (I have a jar of used ones salvaged
from old
m.waves). While working on it we defeated the hi voltage to
the
magnetron. For safety.
When the owner had reassembled his m.wave he had not put the
cover
back on correctly and there was a potential leak on the
right hand
edge very close to the door opener and close to where one
would put a
hand to program or switch off! The 'edges' of the cover and
the case
were improperly meshed ............... Strewth; do wish
people
wouldn't touch stuff they don't understand!
For example I know nothing about automatic transmissions so
I would
not 'go at' one. I'm also a very poor plasterer, so hands
off.
Everyone having fun? Within their capabilities.

stan wrote:
Recently an acquaintance asked us to 'look at' his favourite
microwave. He'd opened it and couldn't find the problem. He felt it
could be the control board!!!!!
My son, also a technician, and I fixed it in about 15 minutes on the
kitchen table; a bad door micro-switch!

I've repaired 5 or 6 microwave ovens and the problem was always a bad
micro switch. Most of the bad switches were caused by a slip on wire
connector making poor contact and getting hot, so I often soldered the
wires to the new switch.

In article
,
stan wrote:

do wish people
wouldn't touch stuff they don't understand!

I guess you don't believe in learning, then.

The couple I've done, it's been the high voltage diode that
goes.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Tony" wrote in message
...

I've repaired 5 or 6 microwave ovens and the problem was
always a bad
micro switch. Most of the bad switches were caused by a
slip on wire
connector making poor contact and getting hot, so I often
soldered the
wires to the new switch.

On Sep 29, 8:59*pm, "Stormin Mormon"
wrote:
The couple I've done, it's been the high voltage diode that
goes.

--
Christopher A. Young
Learn more about Jesus
*www.lds.org
.

"Tony" wrote in message

...

I've repaired 5 or 6 microwave ovens and the problem was
always a bad
micro switch. *Most of the bad switches were caused by a
slip on wire
connector making poor contact and getting hot, so I often
soldered the
wires to the new switch.

Interesting. Good idea though. We had a total of three or four m.waves
in a school cafeteria we used to operate. With those and requests from
friends and neighbours we had 2 or 3 bad magnetrons, which even used
cost around $30 so unless you had one out of a scrapped unit hardly
worth fixing! Couple of those over-heat switches (either little round
bi-metal or occasioanlly solid state) that went open, Two IIRC bad
micro switches, one bad diode and or capacitor can't recall which.
Then also encrusted dirt, bad fan etc.

Stormin Mormon wrote:
The couple I've done, it's been the high voltage diode that
goes.

Well I sent them to you since I stock micro switches but no HV diodes.

Curious, what are the symptoms of a bad diode? I just thought about it,
I suppose they (almost)never short out, and an open one may act as if
the oven was working but nothing gets hot?

On Sep 30, 1:49*pm, Tony wrote:
Stormin Mormon wrote:
The couple I've done, it's been the high voltage diode that
goes.

Well I sent them to you since I stock micro switches but no HV diodes.

Curious, what are the symptoms of a bad diode? *I just thought about it,
I suppose they (almost)never short out, and an open one may act as if
the oven was working but nothing gets hot?

The diode is in a simple partial voltage doubling circuit. If it dud I
think you'd get AC at reduced voltage on the magnetron? Probably not
high enough to produce microwaves?
In simple terms IIRC the HV capacitor (usually about 0.8 mfd.) charges
up on one half cycle (60 hertz) and then discharges on the opposite
half cycle in series with the already charged capacitor. Thus
providing pulses of HV DC at approximately twice peak voltage of the
transformer HV winding output.
A recent bench test showed that one particular transformer had a 21:1
ratio. So with 115v RMS into the primary, the HV would be 2415 RMS
and somewhere around 3400 volts peak. Double that minus some losses
etc. we are looking at around 5000 volts DC.
And unlike the HV in a colour TV which is a few milliamps or even
microamps to a picture tube CRT, in a high impedance circuit, the
power fed to a magnetron can be a quarter to half an amp or more; at
around 5000 volts DC!!!!!!!! Anything from 750 to 1500 watts etc.
Welcome to your own private electric chair; eh?
Cheers.

No heat, loud hum. And, I sent you the ones with the bad
microswitches, which I don't stock.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Tony" wrote in message
...
Stormin Mormon wrote:
The couple I've done, it's been the high voltage diode
that
goes.

Well I sent them to you since I stock micro switches but no
HV diodes.

Curious, what are the symptoms of a bad diode? I just
thought about it,
I suppose they (almost)never short out, and an open one may
act as if
the oven was working but nothing gets hot?