Figuring out speaker problems

bg4533 · 21st August 2005, 06:25 PM

I have a pair of Mission M73s that are having problems. A digital amp I was modifying went nuts and sent some trash through the speakers. The midranges are fine, but the tweeters in both speakers work sometimes and don't work others. I don't want to ship these back to Mission so I plan on fixing them myself. Is my problem just with the tweeters or is it possible the crossover has problems too? Is there an easy way to test for damage to the crossover and the tweeters? There is no visible damage.

Thanks.

Cal Weldon · 22nd August 2005, 03:39 PM

It may be a fried cap or there may be something with the tweet. Pull the tweets to test them. Do the speakers have an L-pad?

Cal

bg4533 · 22nd August 2005, 05:32 PM

No L-Pad on the speakers.

I did a few measurements, but I don't know what is valid.

I played a 6000Hz sin wave through the crossover. Voltage measured higher on the output side. I am not sure how to measure current or resistance of the crossover. I will try testing the caps later.

The tweeter measures a resistance of around 6ohms. I will try playing a sin wave directly through the tweeter and see how it reacts.

Since the problem is intermitent it might be a bit hard to diagnose.

bg4533 · 22nd August 2005, 05:33 PM

Also, the crossovers have 2 inductors. I know nothing about inductors and don't have a meter that will measure them. Is it common for inductors to die?

Cal Weldon · 22nd August 2005, 05:38 PM

No, that is rare.

Try tapping the components to see if you can find something loose while testing.

21st August 2005, 06:25 PM	#1
bg4533 diyAudio Member Join Date: Aug 2004 Location: Ohio	Figuring out speaker problems I have a pair of Mission M73s that are having problems. A digital amp I was modifying went nuts and sent some trash through the speakers. The midranges are fine, but the tweeters in both speakers work sometimes and don't work others. I don't want to ship these back to Mission so I plan on fixing them myself. Is my problem just with the tweeters or is it possible the crossover has problems too? Is there an easy way to test for damage to the crossover and the tweeters? There is no visible damage. Thanks.

22nd August 2005, 03:39 PM	#2
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	It may be a fried cap or there may be something with the tweet. Pull the tweets to test them. Do the speakers have an L-pad? Cal __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

22nd August 2005, 05:38 PM	#5
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	No, that is rare. Try tapping the components to see if you can find something loose while testing. __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

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22nd August 2005, 05:32 PM	#3
bg4533 diyAudio Member Join Date: Aug 2004 Location: Ohio	No L-Pad on the speakers. I did a few measurements, but I don't know what is valid. I played a 6000Hz sin wave through the crossover. Voltage measured higher on the output side. I am not sure how to measure current or resistance of the crossover. I will try testing the caps later. The tweeter measures a resistance of around 6ohms. I will try playing a sin wave directly through the tweeter and see how it reacts. Since the problem is intermitent it might be a bit hard to diagnose.

22nd August 2005, 05:33 PM	#4
bg4533 diyAudio Member Join Date: Aug 2004 Location: Ohio	Also, the crossovers have 2 inductors. I know nothing about inductors and don't have a meter that will measure them. Is it common for inductors to die?

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