Appliance Bulb Filament Continuity

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The light in my GE microwave quit coming on so after pulling the case apart to get at it (great design, guys!), the filament of this 25 watt plug in bulb looks intact. However, a meter across the two male terminal spades shows no continuity.
There's power at the connector supplying the light when the door is open or the oven is running-- so that's not the problem. Could the bulb be bad even when it shows continuity?
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Make that ...NO continuity....
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bad bulb ........
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Charlie Darwin wrote:

yes, NO continuity mean bad bulb. duh.
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*NO continuity equals a broken filament. Replace the bulb.
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Happens often Spend the 2 bucks for a new one.
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bad
You are asking if a burned-out bulb is bad? This is why I don't believe in evolution.
If you stick it in another (more portable) lamp and flick it with your fingernail while it is on sometimes the filament will reconnect and weld itself back in place. This, of course, works better with DC than with AC. I have fixed many incandesant bulbs this way.
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Better reread the OP a bit more carefully and The Origin of the Species too ;-)
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Charlie Darwin wrote: ...

Might "otter" check on the title of the work...
--
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On Sat, 21 Feb 2009 15:06:25 -0500, Charlie Darwin wrote:

What an imaginative work of fiction!
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watt
AC.
too
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 :-|
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OK guys-- off to the appliance parts store. I'll post back later...
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Parts guy was stumped by the intact filament/no continuity too (see Van's post). But I decided to try a new bulb (for $11.24.
It shows continuity.....and works. Thanks to all for the helpful suggestions.
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Charlie Darwin wrote: ...

Just because you the break was visible doesn't (obviously) imply it was/is intact. Nor, of course, that the fault could be at the connection of one end of the filament to the base, etc., ...
When it doesn't light and measures open, it's pretty clear it's defective.
--
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What is so special about the bulb that they can get that price? You can probably find it cheaper on the internet but then the S&H would be $10.
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wrote in message

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.
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Charlie Darwin wrote:

Perhaps one day they will switch to LED lighting. The only problem is the LED's may not get along with microwave radiation.
TDD
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<edit down story of hard-to-replace bulb to reduce line count>

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 ( snipped-for-privacy@misty.com)
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Don Klipstein wrote:

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
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