Author Topic: Yamaha Speaker troubleshooting  (Read 2896 times)

Offline sean283

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Yamaha Speaker troubleshooting
« on: July 30, 2014, 09:38:11 AM »
Hi Folks, it's been awhile.
Life is settling down at last and I have time to play with audio again.

So, years ago Tom hooked me up with a pair of Yamaha NS-690II speakers.
Love those things and I've been waiting for another pair to surface.
All the ones I've seen are always 1000 miles away and very expensive. 

The other day, I snatched up a rather beat up and inexpensive pair.
Work? Of course, not. When a seller says "sounds great", just assume it doesn't work.

You get what you pay for right? Anyway, one of the mids isn't working.

I put a meter on the voice coil and it is showing continuity and reading about 3 ohms or so. So, the voice coil isn't open.
I metered out the L-pad for the mid and it appears to be working (0 to around 7 ohms).

So, I guess that leaves the crossover.
do you think a crossover cap failed open? Or?

Comments? Suggestions?
 
SS system 1 - Conrad Johnson PV-10AL  Carver TFM-25 Carver DTL-200 MKII Carver C9 River Current RC8- Yamaha NS-690II Yamaha NS-670
SS system 2 - Sansui 9090DB Snell EII  Tascam CD-RW700
Tube system - Akai X-150D H.H. Scott 99-D (2)  Sony MDS-JE510 Bozak B-302A

SunnyDaze

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Re: Yamaha Speaker troubleshooting
« Reply #1 on: July 30, 2014, 12:38:32 PM »
Did you measure the DCR of the overall speaker at the terminals?

What is the impedance of the midrange driver? 4 Ohm, I'm assuming?

Offline AdamG

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Re: Yamaha Speaker troubleshooting
« Reply #2 on: July 30, 2014, 01:37:58 PM »
Since you have a pair, and one works and the other doesn't you have the perfect testing dummy to work off of. See what matches between the two and what doesn't match. There may be a lifted trace on the crossover if it uses a board or it may be a cap that has dried out entirely some how.

Dicky

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Re: Yamaha Speaker troubleshooting
« Reply #3 on: July 30, 2014, 03:06:55 PM »
Not that it means much, but the last few bad crossovers I came across you could visually see that they were bad (burn marks, etc). 

Offline Reverend

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Re: Yamaha Speaker troubleshooting
« Reply #4 on: July 30, 2014, 03:40:26 PM »
Good to see you're still alive Sean!