How To Take Apart A Microwave

Step 4: Discharge the capacitor

Locate the capacitor, it should be near the big fat chunk of metal, the high voltage transformer. Then get your alligator clips and very carefully touch both terminals of the capacitor...

You may get an loud "SNAP" (which is unlikely) and that indicate the capacitor is discharged, do this a few more time to really make sure the capacitor is discharged..

And you're done! The microwave is safe to gut out!

Comments

[solaralternatives]

If you REALLY want to be safe, use a HEAVY bladed screwdriver (preferably one from a yardsale - cheap, and you don't care if the super-powerful electrical arc pits the metal!) then measure the voltage on the cap with a multimeter set on highest setting. Better to blow up a cheap meter (such as those sold @ harbor freight) than.. to die.

[deaks]

i've also heard it said that when one is in a tight spot (as this one looks to be) use two junk screwdrivers crossed so they are touching (hold one in each hand). that way, you don't have to get in at a right angle to the cap to touch it or get really close like with the alligator clips.

also, using two, if you are startled and drop them, they will always fall OFF of the cap. using a single screwdriver, you will occasionally weld the screwdriver to the cap you are discharging.

just some thoughts.

[Vulnic]

I'm still very concerned about discharging the capacitor. Would it make it any safer to use one of those wrist chords used when building/fiddling around inside a computer to clip onto something metal and ground you?? I mean it's not as if you get another shot at this if it goes wrong.... like they say 'There's not many DUMB electricians left in the world ... they're all dead"

[strongclad]

I've read elsewhere on the internet (http://www.doityourself.com/stry/repairmicrowave) that you should go about discharging the capacitor another way. Is this a better/safer way of discharging the capacitor?

"you will need the following: a screwdriver, a wire-wound resistor with a 2 watt-20,000ohm rating, and a pair of jumper wires with alligator clips on the ends. Clip a wire to each end of the resistor. Clip one wire to the metal shaft of the screwdriver. Clip the other wire to one of the capacitor's terminals. Now, touch the other terminal with the tip of the screwdriver. There may be a small spark. If the capacitor has three terminals, do the same process with the middle terminal and each outside terminal."

I've also read that you should do the same from each terminal to the chassis.

[Plasmana]

His method is safer, however, I prefer to do the simple and harsh way, lol.

[strongclad]

What about the screwdriver? I've gone looking for one that has a well insulated handle, but I can't find any that list this feature on the packaging. The only screwdrivers I've found that say so explicitly are ones that also insulate the entire shaft except for the tip. Are there any screwdrivers that you may know of that insulate only the handle?

[LiquidLightning]

Yes, the ones with a rubber or plastic handle.

[bobbyrae]

This looks wrong! Connecting a wire to both sides of the capacitor will do nothing! You have to connect each side to GROUND, one at a time.

Hey folks, here' s link to a guy who understands microwave repair really well:
http://www.repairfaq.org/sam/micfaq.htm. Has better details on doing this discharge thing.

[tristantech]

No that will not work because that does not create a complete circuit.

[morganw]

if you connect a wire from one terminal of a capacitor to the other terminal of the capacitor it will fully discharge it. If you were to connect a wire from one terminal of a capacitor to ground it wouldn't do anything unless the other terminal of the capacitor was already attached to ground which it may or may not be, most likely not.

[bobbyrae]

If morganw is correct, then it wouldn't be possible to get shocked by a capacitor unless you touched both terminals at once, but we know that is wrong don't we?

For some reason, the link I originally posted is now bad. here is a better one:

http://repairfaq.ece.drexel.edu/sam/micfaq.htm#micsafdc

This guy is obviously experienced at this stuff and all I am doing repeating his good advice that I heard from several sources.

Frankly, I don't think Instructables should even allow these how-to's when there is a potential for DEATH due to the person giving the WRONG instructions.  Even if the instructions are correct, someone can misunderstand, die, and then sue over that anyway. 

[Jimmy Proton]

you fail, you can fully discharge a capacitor by shorting the leads, i work with them a lot so i would know.

[gen.badger]

well if common sense tells anyone anything, it is that you should do your own research before you attempt an instructable that is dangerous. he warned of danger and that's enough. if you dont fully understand the electronics and the danger that accompanies them, then they have no business attempting it.

PS: one cannot sue if they are no longer alive...

PSS: good job with doing your research, is is always a good idea to consult an expierenced person before attempting this type of project. but remember, there is always more than one right way to do things. you can discharge a cap in many ways, all leading to shorting the two terminals, whether it is direct or through grounding them both simultaneously. btw join ninja inc... my group.

[melkor80142]

is it just one alligator clip w/ the opposite both sides touching opposite sides of the capacitor.