# Sharp microwave oven problem

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#### Pat

Jan 1, 1970
0
My Sharp convection microwave (model R-9H66) trips the circuit breaker
everytime it's turned on. It started doing this after its door was slammed
shut by someone. It's obviously shorting somewhere when turned on, and I
took the outer housing off to look at the wiring to see if there was
anything obvious,but didn't notice anything.

Does anyone have any idea what might be wrong or what to look for? It was a
fairly expensive unit when I bought it 6 years ago, and I'd hate to just
through it away, especially if it turns out to be something relatively easy
to repair.

Thanks for any help. I appreciate it.

Pat

B

#### Bob Shuman

Jan 1, 1970
0
I'm not familiar with your model or unit, but there are safety interlocks on
every microwave to assure the door is properly shut to prevent radiation
leakage. These usually come in two flavors, a normally open microswitch
that gets closed to "make" the connection to power the magnetron, and a
second normally closed microswitch that is normally shorted across the
magnetron and opens when the door is shut.

These two switches work in combination and if all works properly, the short
is removed and the power is then applied. In your case, I'd look at the
switch and the alignment to make sure the one that opens is in fact opening
properly. Sounds to me like it may have been jarred and is no longer aligned
properly so stays closed creating the short and blowing your breaker (most
units I've seen have a 15A slow blow fuse that goes first before the
receptacle breaker).

Good luck and hope this is helpful.

Bob

J

#### Jerry G.

Jan 1, 1970
0
Check for defective safety switches, and replace as necessary. It is rare,
but there may be a short in the power supply, or the HV section.

Take care that these are extremely dangerous to service yourself, unless you
really know what you are doing. As for replacing the safety switches, use
the origional manufacture parts only, and make sure you know how to adjust
their placement. Check for the proper tollerance of how the door seats, and
that the play in the hinges is correct.

After replacing any components, especialy around the door area, it is
strongly recomended to take measurments for any possible radiation leakage,
in case the door may not be seating properly. If the door has been slammed
so hard to damage the switches, a radiation leakage test would be in good
order.

I would recomend that you take the unit to an authorized service center
where they service microwave ovens, for proper and safe service, unless you
are properly trained, equiped, and are experienced in this type of service
work. The microwave oven is the number one dangerous appliance in the home.
The next ones down are the TV set, and the computer monitor.

As for microwave radiation, at low levels this is not able to be felt, but
damage may be done to anyone within its range. There are numerous safety

D

#### dkuhajda

Jan 1, 1970
0
FYI: I Never work on Microwave ovens. They simply are not worth the
trouble or RISK to me. Realize that the capacitor in a microwave oven
stores a charge roughly equivalent to the LifePak defibrillators we are
seeing advertised on tv. If you get across it the wrong way with it
unless medical help arrives in a few minutes, at a minimum you just did
damage to your heart. That would be during the T wave of your EKG.

At the very least, everyone I know who works on microwave ovens now, has
insulative gloves up to the elbows on at least one arm AND double checks
the high voltage stored on the capacitor with a high voltage probe.

My suggestion, pay someone the $50 labor to work on it for you. If someone really does not know exactly what they are doing and is willing to accept the risk,$50 or so, is simply not worth the risk for the average Joe
owner.

David

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#### Art

Jan 1, 1970
0
Read the RepairFaqs regarding these infernal machines before even attempting
service. There are many posts to Sam's Site within this and other
newsgroups. As stated, these can be EXTREMELY DANGEROUS to service for the
un-informed. Occasionally LETHAL!! BTW, I agree that it is highly probable
a defective or miss-aligned switch, exp since some how "the door had been
slammed"!!

S

#### Sam Goldwasser

Jan 1, 1970
0
Art said:
Read the RepairFaqs regarding these infernal machines before even attempting
service. There are many posts to Sam's Site within this and other
newsgroups. As stated, these can be EXTREMELY DANGEROUS to service for the
un-informed. Occasionally LETHAL!! BTW, I agree that it is highly probable
a defective or miss-aligned switch, exp since some how "the door had been
slammed"!!

And if the oven is unplugged, working around the area of the door switches
is safe. However, you do have to know where that is and where NOT to go!

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
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Important: Anything sent to the email address in the message header is ignored.
To contact me, please use the Feedback Form in the FAQs.

K

#### Ken G.

Jan 1, 1970
0
Now that you scared the guy to death .....

its probably a door switch that jammed when someone slammed it . look in
where those plastic spades on the door poke into the front there are
some squarish black switches that get pushed when the spades go through
the holes .
Each switch has a little ( probably ) red nub that clicks when you push
it in . You can reach in and push those with something to see if they
mechanically click .
If you do find the bad one you can unplug the wire from the back of it
and note where they went and take the switch to some repair senter for a
new one . Put it back the same way it came out . You dont need to do any
of those silly tests .... those are for ovens that ha door damage .
Just dont touch the wires coming out of a big capacitor ( silver oval
like can mounted to the bottom or rear of the case )

P

#### Pat

Jan 1, 1970
0
Thanks to everyone for all the replies and warnings. I've worked around
electronics before and know stay away from the caps or make sure they're
discharged and everything is unplugged if I must go near them.

If it turns out to be a bad switch (as seems likely) where's a good place to
get a replacement?

Thanks again. -Pat

B

#### Bob Shuman

Jan 1, 1970
0
Pat,

I generally look in the owner's manual and contact the manufacturer (using
the phone number listed or a visit to their web site) or the closest
authorized service center. Usually you can order parts, especially the
commonly replaced items like the microswitches, diode, HV capacitor, etc.

Another option I've used is at the following repair web site:

http://www.repairclinic.com/0047_6.asp

They handle parts and provide a lot of basic troubleshooting info, assembly
drawings, etc. for many common appliances in use today. In either case, be
prepared to pay more than what you might expect since you are paying for the
convenience of having the distributor stock these items and not just the
manufacturing cost.

Good luck and exercise caution when working on the microwave.

Bob

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#### Pat

Jan 1, 1970
0
It's fixed!

Turns out one of the switches had been pushed slightly out of the plastic
bracket that was holds it in place, although it wasn't real obvious until I
looked closely. When I pushed on the back of it, it snapped back into place
and everything started working again as normal. It must have been knocked
out of place when the door was slammed.

A very easy fix after all, but I would have never found it if someone hadn't
suggested checking it.

Thanks again to everyone. You've save me several hundred dollars. Does
make me wonder how many microwaves end up by the curbside because of simple
things like that.

Thanks again,

Pat

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#### NSM

Jan 1, 1970
0
| It's fixed!
....
| Thanks again to everyone. You've save me several hundred dollars. Does
| make me wonder how many microwaves end up by the curbside because of
simple
| things like that.

It's said that microwaves don't burn out, they rust out. My 20 year old one
still works after daily use, long after I thought it would die.

N

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