Yamaha cinema speaker problem help

Thread Starter

Satman17

Joined Feb 19, 2021
12
Hi

my first post so be gentle with me and any help would be appreciated please.

i have a problem with a Yamaha cinema speaker where the centre tweet has stopped working, I have checked the resistance of it which is 6ohms and it seems ok, inside the speaker is a crossover and I suspect the capacitor has come to the end of its life and while in at it the resister I might change the problem is the capacitor in brown has little markings on which I can understand and any help id’ingit would be great also the best and cheapest place to buy the capacitor and resister would be great .

thanks once again
 

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wayneh

Joined Sep 9, 2010
17,152
Hi

my first post so be gentle with me and any help would be appreciated please.

i have a problem with a Yamaha cinema speaker where the centre tweet has stopped working, I have checked the resistance of it which is 6ohms and it seems ok, inside the speaker is a crossover and I suspect the capacitor has come to the end of its life and while in at it the resister I might change the problem is the capacitor in brown has little markings on which I can understand and any help id’ingit would be great also the best and cheapest place to buy the capacitor and resister would be great .

thanks once again
I think the information you need about the capacitor is facing down. You need to bend it up to get a better look. Or just take it out if you're replacing it anyway. I'd probably just snip the leads close to the capacitor instead of trying to desolder it. Replace by soldering to the cut leads.

I'd also take a button cell battery and tap power to the speaker element, to confirm it clicks when power is briefly applied. Or connect it to something that can drive a 8Ω speaker and confirm it can reproduce audio.

I have Yamaha speakers. Just curious, which model do you have?
 

Thread Starter

Satman17

Joined Feb 19, 2021
12
Not much in price really just a little concerned that the cap says 4.7k and what’s written on the new one is 4.7uF
 

Jon Hoover

Joined Oct 10, 2019
33
The brown capacitor is an 8.2 uf @ 100 volts electrolytic type capacitor. Since this is used in a crossover network, it should be replaced with a NON-POLARIZED capacitor. Make very sure you use that type as those are designed for the application you have. The yellow capacitor appears to be a 4.7uf with the letter K designating a 10% tolerance. The crossover frequency of a 2nd order Butterworth filter at 4.7uf with an 8 ohm speaker is in the neighborhood of 3000 hz. It is a film type capacitor and they rarely fail like the electrolytic ones do. They can fail if there is too much voltage applied and it breaks thru the internal insulation but it would usually show some damage if that were the case. It wouldn't hurt to replace both. As for the voltage ratings, 100 volts is what they are both rated at. You can go higher but the capacitor itself would be physically larger. Just don't go any lower. Regarding sourcing, Parts Express is a great source of crossover components and they have a very good customer service department that will help you choose the correct parts for your application. Digikey and Mouser are also great sources but they may not hold your hand and guide you thru the parts selection process as well as the Parts Express folks will. You might also want to check the continuity of your coils. If one of them is open, that would make your tweeter not work. Use your volt meter and set it to ohms. Wayneh had a great suggestion too. Use an AA or AAA battery and quickly touch the speaker wires to the battery terminals and listen to see if the speaker makes scratching noises. If it does, then the speaker is ok. If it does not, then the speaker is probably bad and should be replaced. Do not use a bigger battery or a 9 volt to do this as it may damage your speaker. I like the AAA ones as they are very low voltage and current and there isn't much chance that they will damage your speaker. Good luck!
 
Last edited:

Audioguru again

Joined Oct 21, 2019
3,176
The capital K on a capacitor is 10% tolerance, a J is 5% tolerance and an M is 20% tolerance.
If it was marked with a small letter k then 4.7k might be 470 thousand farads and it would be the size of a car.

I looked for a 630V film capacitor in Digikey but they do not have any because nobody needs a 4.7uF film capacitor with such a high voltage today. A 400V one costs 5 US dollars.
 

Thread Starter

Satman17

Joined Feb 19, 2021
12
The brown capacitor is an 8.2 uf @ 100 volts electrolytic type capacitor. Since this is used in a crossover network, it should be replaced with a NON-POLARIZED capacitor. Make very sure you use that type as those are designed for the application you have. The yellow capacitor is a 4700pf/4.7nf/0.0047uf film type capacitor. It is probably ok since it is a film type capacitor and they rarely fail like the electrolytic ones do. They can fail if there is too much voltage applied and it breaks thru the internal insulation but it would usually show some damage if that were the case. It wouldn't hurt to replace both. As for the voltage ratings, 100 volts is what they are both rated at. You can go higher but the capacitor itself would be physically larger. Just don't go any lower. Regarding sourcing, Parts Express is a great source of crossover components and they have a very good customer service department that will help you choose the correct parts for your application. Digikey and Mouser are also great sources but they may not hold your hand and guide you thru the parts selection process as well as the Parts Express folks will. Wayneh had a great suggestion too. Use an AA or AAA battery and quickly touch the speaker wires to the battery terminals and listen to see if the speaker makes scratching noises. If it does, then the speaker is ok. If it does not, then the speaker is probably bad and should be replaced. Do not use a bigger battery or a 9 volt to do this as it may damage your speaker. I like the AAA ones as they are very low voltage and current and there isn't much chance that they will damage your speaker. Good luck!
Thank you
 

Jon Hoover

Joined Oct 10, 2019
33
The capital K on a capacitor is 10% tolerance, a J is 5% tolerance and an M is 20% tolerance.
If it was marked with a small letter k then 4.7k might be 470 thousand farads and it would be the size of a car.

I looked for a 630V film capacitor in Digikey but they do not have any because nobody needs a 4.7uF film capacitor with such a high voltage today. A 400V one costs 5 US dollars.
My bad. I just realized that right after I posted it. My post has been edited with the correct information.
 

wayneh

Joined Sep 9, 2010
17,152
I thought the yellow piece was a resister rated at 4.7k and not a capacitor, anyway I have the information of the brown capacitor picture attached
Did the capacitor get damaged when you moved it for the picture?
It certainly needs to be replaced now. That must be some tough glue.
 
Last edited:

Audioguru again

Joined Oct 21, 2019
3,176
Post #9 wrongly said the yellow capacitor value is 1000 times too small has been corrected to 4.7uF.
A quote in post #11 copied the wrong value of the capacitor.
 
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