Re: Microwave oven capacitor.. Dead short overnight?

maradcliff@xxxxxxxxxxxx wrote in
news:qt9bs1pj7h11ted47j1kihvtg0pq2vpu7j@xxxxxxx:

> On Tue, 10 Jan 2006 23:07:34 GMT, "Rich256" <nospam@xxxxxxxxxx> wrote:
>
>>
>>"Robert Mech" <mech@xxxxxxxxxxxxxxxxxxxxxxx> wrote in message
>>news:43c43526$1@xxxxxxxxxxx
>>> In article <Xns97404CDA99443herhusband@xxxxxxxxxxxxxx>,
>>> HerHusband <unknown@xxxxxxxxxxx> writes:
>>> |> Doug,
>>> |>
>>> |> > It worked OK last night, I popped in a meal tonight, pressed
>>> |> > the button.. Overload hum, blue flash from the back, then no
>>> |> > display (10 year old Sharp model.)
>>> |>
>>> |> > Since my background is in electronic repair, I opened it up.
>>> |> > put a
>>new
>>> |> > fuse in, tried again and saw the flash location, near the big
>>> |> > cap in the rear.. (Unplugged, checked for charge, then metered
>>> |> > it. 2
>>ohms!)
>>> |>
>>> |> I worked as a microwave tech for about six years. Be VERY careful
>>working
>>> |> with those capacitors. They can store one heck of a charge, even
>>> |> weeks
>>or
>>> |> months after the oven has been unplugged! We always discharged
>>> |> the caps with an insulated screwdriver across the terminals. One
>>> |> big "POP" and
>>flash
>>> |> I never got used to! :)
>>>
>>> A few years ago there was a news report from my hometown
>>> about someone working on his microwave oven. That capacitor
>>> electrocuted him.
>>
>>He probably had a bad heart or was working in that area with the power
>>on. It would not electrocute a normally healthy person. More likely
>>get killed by bumping your head when jumping back away from it. Kind
>>of similar to the voltage on a TV tube. You don't accidentally touch
>>it twice.
>>
>>I was in a lab where a guy working on a very high powered radar system
>>got hit by a string of large capacitors charged to 30,000 volts. It
>>knocked him clear across the room. Fortunately the power was off.
>>
>>Doing a "crowbar short" to that system you could draw an arc over a
>>foot long.
>>
>
> I agree. I got zapped off the old tube type tv sets many times as a
> child, and being a farmer, I get zapped off my electric fences at
> least 5 times a year. A person dying from this either has a weak
> heart, or as you said, the power was on.
>

The worst damage comes from pulling your arm back and ripping it on a sharp
piece.
MW oven caps are only around 2KV,and fairly small in capacitance,compared
to a high power radar system,or broadcast transmitter.


> Unplug the device (always do that with anything). Then place a
> screwdriver with a well insulated handle across the cap, and proceed.

I prefer a 1 Kohm 2W resistor glued on a plastic stick.(old tuning tool)
(unit unplugged and OFF.)


> Besides, we have the Bush administration
> to instill fear in us now. Thats their job. They'll probably tell
> you the microwave repairman is a terrorist, if you ask them....

Now that's nonsense.

The Bush administration is doing a FAR better job than Clinton did,or Kerry
would have done.(and the terrrorism threat is REAL.)



--
Jim Yanik
jyanik
at
kua.net
.

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