[TechAssist] Re: Emerson Microwave MW8107WAC blows fuse once in a while, [UPDATE]

  • From: Doug Keller <dek@xxxxxxxxxx>
  • To: techassist@xxxxxxxxxxxxx
  • Date: Wed, 05 Mar 2003 08:04:30 -0500

Back during the Christmas season, Jay told me at one of the
stores they were at shopping, they had microwaves for $34.99.
I told him to go buy one, throw it on the bench, remove the
magnetron, then call to price a new one. Would be $40-$45 at
least, plus shipping. If you charged ZERO for labor on this
stuff, the customer STILL has more in it than it would cost to
just replace with another new one! This is the whole problem
in trying to make a living at repair today. I wish the federal
government would look into this. We have no voice in
government, unfortunately, and I myself have no idea of where
to even start.
Doug

teltek3 wrote:
> 
> Gary;
> Adding a Thermal cut-off switch to the magnetron would add to the price
> of$79 to $80.
> Does the sticker say Emerson or just "E". Thought they might cut some
> corners there..too. But then it might be mistaken dor Electrohome, and
> Citizen bought that logo.
> You can't add a magnetron to a Kenner Easy Bake Oven, and try to market it
> as a Micowave.
> I think "UL" and "CSA" labels must be marketed by the roll these days..;-)
>     If you're going to take the time to disect one of these, at least work
> on a Toshiba or Panasonic.
> Microwaves....like VCR's are bought as a disposable item these days.
> Been there.
> 
> -Ed-
> .
> Tel-Tek Electronics
> Ontario-Canada
> 
> teltek3@xxxxxxxxxxxx
> ----- Original Message -----
> From: "Gary McCartney" <gary@xxxxxxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>
> Sent: Tuesday, March 04, 2003 11:53 PM
> Subject: [TechAssist] Emerson Microwave MW8107WAC blows fuse once in a
> while, [UPDATE]
> 
> >
> > Thanks everyone, very much for all the excellent suggestions. I want to
> > try to get to the bottom of this, just to know if it can be solved, even
> > though a lot of time will be spent.
> >
> >
> > One thing I notice, at least since I put the oven back together, is that
> > the door is a bit flimsy and if you push the door shut from the very
> > bottom, sometimes the top latch doesn't catch. I tried to adjust the
> > safety switch assembly so the door would latch better, and that helped
> > but not perfectly. If the door is held in the center while closing it,
> > then no problem. I checked the fuse holder. It looked like new but I did
> > squeeze the posts together so the fuse would be held tighter. The old
> > fuse lokked good. No solder dripping out the end caps. Also, I inspected
> > the waveguide opening for any foreign junk but it was very clean. The
> > waveguide cover is plastic and it is like brand new. The fan spins like
> > it should and the air holes are clean.
> >
> > I put the top on the oven so the air flow would be proper, then I boiled
> > water for 4 min. and unplugged the oven. Unit didn't have as noticable
> > smell as it did before (or am I just getting used to it?), so I put top
> > on again and cooked for another 5 minutes. After it finished, I felt the
> > cavity for heat. It seemed to be fairly warm all over and the yellow
> > areas felt about the same temperature as anywhere else. The transformer
> > was hot enough that I didn't want to hold my hand on it. The smell was
> > still not as strong as before. Then I tried another capacitor of same
> > value. Didn't change operation any. When I went to remove the magnetron
> > to check how the antenna probe looked, I noticed that the connections to
> > the magnetron filament were on backwards. The lead to the HV rectifier
> > went to the "F" terminal instead of the "FA" terminal as is the case on
> > other microwaves I have sitting in my shop. I found another magnetron of
> > the same number and installed it with connections back to normal. Cooked
> > water for 5 minutes, then pulled cover off. Everything still seems as
> > hot as it was before. Only thing left is the transformer. I will look to
> > see if I have one tomorrow. I'm wondering if it isn't the nature of the
> > beast to be so hot, afterall, these things are built as cheap as
> > possible. I see they don't have the thermal cut-off mounted on the
> > magnetron like older microwaves (it's on the top edge of the oven
> > cavity). Maybe this is a sign the mag is supposed to run fairly hot?
> >
> >
> >
> >
> > Gary McCartney
> >
> > McCartney Electronics
> > 7134 Fife Rd, RR 7
> > Guelph Ontario Canada N1H 6J4
> > Fax: (519)821-1530
> > email: gary (at) number63.ca
> >
> >
> >
> >
> >
> >
> > My original message:
> >
> >
> > I have this Emerson Microwave, model MW8107WAC in the shop. This oven is
> > only about a year old. The customer has brought this back to me the
> > second time now with 20A fuse blown. He claims he hardly uses the oven
> > so maybe it cooks approx. 20 times between fuse blows. Each time I check
> > the safety interlock switches while opening and closing the door.
> > Everything checks ok so I install new fuse and boil water a dozen times,
> > then send unit home.
> >
> > While testing this oven yesterday, I notice a strange kind of odour,
> > seems like it is mainly near the front control panel. Smells a bit like
> > burnt popcorn but hard to describe exactly. It doesn't smell really like
> > electrical burn such as a hot resistor. I was boiling water in a large
> > margarine container at 4 minutes each time. I am trying to blame the
> > smell on the margarine container so I went and used a Pyrex bowl
> > instead. The oven kept producing this smell. I took the front panel all
> > apart and sprayed it with disinfectant and let it sit over night. Today
> > it smells somewhat better but while cleaning out the oven cavity I
> > notice that some of the white paint has turned yellow, particularly a
> > large spot on the rear wall and a smaller spot up front where the vent
> > holes are in the side wall near the control panel.
> >
> > I have powered the control panel away from the oven and it is not
> > producing the smell. Is it the white paint getting hot that is doing it?
> > Why is there spots where the paint has yellowed? The rotating glass tray
> > is in working condition, so I would say the microwaves should be spread
> > around evenly. I removed the waveguide cover and didn't find any dead
> > mice or as such in there, hehehe.
> >
> > Any help appeciated.
> > --
> >
> >
> >
> >
> > Gary McCartney
> >
> > McCartney Electronics
> > 7134 Fife Rd, RR 7
> > Guelph Ontario Canada N1H 6J4
> > Fax: (519)821-1530
> > email: gary (at) number63.ca
> >
> >
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-- 
Doug Keller          "Learn from the mistakes of others,
Wis-Kel Electronics   because you won't live long enough
101 Freeland Ave.     to make them all yourself"
Terra Alta, WV
USA        26764
dek@xxxxxxxxxx
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