Appliance Bulb Filament Continuity

[Charlie Darwin]

Bulb is 25 watt, tubular, about 2 inches tall, integral plastic base with two blades protruding beneath that slide into female connector.

The filament is circular going around the circumference of the glass and is supported by 5-6 separate wire posts -- each topped with a loop to support/lock the filament wire.

The parts people only had a 20 watt, about 1 1/2 inches tall. That's the one I bought and put into the microwave.

No reason a 79 cent standard appliance bulb couldn't have been designed into it originally-- but then again, these are the same guys that forced me to take the entire sheet metal cover off. Good thing I had the right bit to remove the 6 locking torx screws they used to fasten the case.

It's really ridiculous they way so many products are designed by graduate engineers using custom/proprietary parts and sub assemblies when standard parts would do just as well. Adds cost, complexity, assembly errors--- and no real benefit to the end user.

[mm]

It still might vibrate when flicked. Depends on where it breaks.

Then your lightbulb is bad, whether the filament vibrates or not.

[Ulysses]

Hmmm... I re-read it and it looks like you asked if a bulb does not light up and shows no continuity... obviously I'm missing something here... maybe I decended from the other race of humans :-|

[Don Klipstein]

Bulb shows lack of continuity and fails to glow, but filament appears intact.

I have seen this before. Bulb is bad. Usually the bulb is bad by having a nearly-miscropic-small break in the filament, though bulbs can break elsewhere less visibly.

- Don Klipstein ( [e-mail])

[Don Klipstein]

I suspect microwave oven manufacturers want people to only disassemble the cases if the disassemblers are technicians or engineers who are likely to know the hazards of operating the darn thing with the case disassembled or incompletely assembled.

One alternative would be making the bulb user-accessable from inside the cooking cavity, but the bulb would probably fare poorly if both powered and subject to the cooking microwave radiation - especially if the consumer finds a gas-filled variant. (Gas-filled lightbulb in a microwave can make nice puictures and videos for adventurous abuse of lightbulbs and microwaves - but that is "great opportunity" for "Things To Go Badly Wrong"!) That can be fixed by the bulb being behinnd a removable/replaceable screen - to the extent consumers put the removeable screen back into place (Ha-ha-ha!!!). I suspect that the manufacturers' lawyers advised the manufacturers that a majority of their customers that voted are responsible for all levels and branches of our government, and that the ones that did not vote on average are even more stupid dummkopfs!

- Don Klipstein ( [e-mail])

[The Daring Dufas]

Perhaps one day they will switch to LED lighting. The only problem is the LED's may not get along with microwave radiation.

TDD

[Don Klipstein]

It appears to me that microwave ovens are designed to impair consumer repairs - for liability purposes.

It also appears to me that choice of lamp type is on basis of reliability, and in part from microwave oven design engineers being more conservative types more likely to give higher weighting to reliability and safety.

It appears to me that such type engineers would choose incandescent over LED because LED lighting has had a lot of overblowing and hype, and because many white LEDs fail to last as long as their proponents claim.

I have seen it to be common practice for incandescent lamps in microwaves to be run at reduced power to extend their life expectancy, so that chanceas are good that the light bulb will not need to be replaced during the life of the microwave. This appears to me consistent with reliability and safety including reduction of repair attempts by consumers.

I suspect that some microwave ovens will soon come out with LED interior lighting, now that there are some white LEDs with actual good expectation to last 30,000 or 50,000 operating hours with only minor to moderate fading.

It should not take too much to protect the LED(s) from the microwaves. I suspect the main hurdle is the extensive testing of something so new and different by a safety certifcation laboratory institution such as UL.

- Don Klipstein ( [e-mail])

[The Daring Dufas]

Many folks don't realize that very bright LED modules require heat sinks to be reliable. I'm sure a perforated screen like what's in the glass door can block microwaves from the electronics of the LED lighting but heat may be a factor too. Heck, old microwave ovens are a great source for parts for us mad scientists.

TDD