Age of microwave

[petmad]

how do i know the age of my microwave ive got model no an serial number

[Max Demian]

You check the date on the receipt you got when you bought it. <g>

Why do you want to know its age?

[Animal]

Didn't give us much to go on did you :)

[Colin Bignell]

Presumably you also know the make. If so, an email to the customer service department of the manufacturer, giving the model and serial number, should get you when it was made.

[Peter Able]

Take off the cover and look at the date codes on the electronic components.

< tin hat on >

PA

[Mike Clarke]

In particular keep well away from the scary big capacitor. It gets charged up to several thousand volts with enough charge to give a serious injury or worse. It can keep its charge for a long time after being switched off so to be on the safe side leave the microwave unplugged for a day or two before removing the cover.

[Andy Bennet]

have you tried carbon dating?

[NY]

Don't big capacitors tend to have a (maybe high) resistance in parallel through which the capacitor can gradually discharge?

[Bob Eager]

If he touches the capacitor, he'll contaminate it with fresh carbon.

[Adam Funk]

AIUI, yes, but very gradually.

[Harry Bloomfield Esq]

If you open it up and look on the pcb, there will be IC's. IC's are always marked with a week and year of manufacture in the form of wwyy. The actual microwave will have been built soon after that date.

[Animal]

usually yes, but the Rs can go oc on occasion. People often say stay away from the cap, but the killer volts are conducted by wires to remote parts of the machine. Easy for anyone that understands the situation, but a death trap for a newb that doesn't.

[Paul]

There are two dangers with microwave ovens.

1) Take the cover off and try and work on it, without appropriate precautions. 2) The danger people don't seem to be aware of, is if the capacitor arcs over, while the microwave is cooking your lunch.

I was present for a (2), and the noise was loud enough, I lost hearing in one year for ten minutes. I thought at first I was f***ed, and had a popped eardrum or something. But the ear eventually started coming back.

The root cause in that case, is too many people at work cooking bag after bag of salted buttered popcorn. This coated the inside of the machine with conductive material. Modern microwave ovens can have things like conformal coatings to try and prevent this.

Strangely, the microwave oven was not damaged, and it was still run-able the next day.

*******

The problem with the microwave, is the potential energy.

1/2CV^2 on the oil-filled cap, is a significant number.

It's three times the energy need to fire a dye pulse laser.

And that's why, if and when it discharges, while fully loaded, you don't want to be standing close to it.

That's the old style transformer-diode-cap 50Hz design. The modern inverter design might have different safety characteristics. Even though the inverter design is better, companies *still* make the legacy kind.

*******

HV arc discharges release ultrasonic energy. One of my chem profs at uni, was deaf in one ear, and all because he did not wear hearing protection while working on pulse lasers. He'd be the first guy to warn you about the dangers of "many, smaller discharges" on hearing. There was a second prof, who used to blow up shit behind a perspex barrier (we don't know why), and his hearing was a bit bad, but he still wasn't wearing protection. He used an arc to "dispatch" stuff.

Those are my favorite kinds of elfen safety examples, the walking and still-breathing kind. You can point to that and say "this is why we wear hearing protection" :-/

But this is what happens when an elfen safety issue takes a lot of attempts, and the degradation is slow and steady. You can be tricked into not wearing protection.

To this day, when I start a microwave oven... I walk away. I wonder why that is... I don't want to experience that a second time.

Paul

[Paul]

Carbon dating might not be far off. They've been around for a while.

"In 1940 British physicists discovered a way for generating invisible electromagnetic waves that could bounce back undetected after contact with a ship or plane. ... Raytheon’s first microwave oven, the Radarange, was bought by a Cleveland restaurant in 1947 for $3,000."

Another article gives specs.

"The first commercial microwave oven was tested in a Boston restaurant in 1947. Later that year, Raytheon introduced the Radarange 1161. It stood 5.5 feet (1.7 meters) tall, weighed 750 lbs. (340 kilograms) and cost $5,000, according to Gallawa. It had to be hooked up to a water line because the magnetron was water-cooled."

So if it has plumbing connections, then 1947 is a guess :-)

Paul

[Animal]

That wasn't a cap arcing, that was the muck in the cooking cavity. Nukes have some other hazards too, but overall safety is much better than stove top cooking.

[jon]

I don't trust any dating site.