Vista woofer stopped working

MartinLogan Audio Owners Forum

Help Support MartinLogan Audio Owners Forum:

L. Guti

New member
Joined
Aug 31, 2021
Messages
4
Reaction score
0
Today I discovered that the woofer in my right speaker wasn't working. I started trouble shooting by switching cables left to right, same problem, so it had to be the speaker. I use clips to connect upper and lower posts, so I then took out the clips and connected the cables only on the top posts. Only highs and mids as it should be. Connected on the lower posts and had no sound, dead. I don't know what else to trouble shoot.
They had been working with no issues for years, same position, same gear.
Any ideas?
 

JonFo

Super Moderator
Moderator
Joined
Jan 16, 2005
Messages
4,374
Reaction score
182
Location
Big Canoe, GA
Hola, this will require opening up the unit to inspect the wiring from the posts to the crossover board, and from the crossover board to the woofer driver itself. One of those could have come loose, broken, etc. Plenty of vibrations inside that cabinet ;)

It also could be a crossover component failure. A quick test is to jumper the binding post outputs directly to the driver inputs, then power just the woofer input with a signal. If you get output, then it's the XO that needs attention. If so, then @roberto can probably help you repair it locally.
 

JonFo

Super Moderator
Moderator
Joined
Jan 16, 2005
Messages
4,374
Reaction score
182
Location
Big Canoe, GA
Here are some links to threads regarding vista woofer / XO issues and how people have dealt with them in the past. Lots of good info there:



And this one had a particularly relevant mention:
" I would like to note that when I examined the black (negative) conductor that powers the woofer directly, I saw that the copper strands were quite oxidized. The speakers is only 3 years old or so. you can see the oxidization in the picture below. "
With the high humidity in Costa Rica, maybe your internal wiring has oxidized.
 

L. Guti

New member
Joined
Aug 31, 2021
Messages
4
Reaction score
0
Thanks for the great info!
I think opening it is the next step, as you mentioned.
It would not surprise me if oxidation was an issue. I will let you know!

Here are some links to threads regarding vista woofer / XO issues and how people have dealt with them in the past. Lots of good info there:
...
 

L. Guti

New member
Joined
Aug 31, 2021
Messages
4
Reaction score
0
Well. I proceeded with the dissection. Took out the bottom and went in to look. Everything looked perfect, no loose cables, no oxide, nothing out of place. Clean and shinny.
Disconected the XO from the speaker and connected the speaker cable from the amp directly to the woofer, bypassing all the circuitry. Just got a very very VERY faint sound on the speaker. Had to put my ear on it to determine if it was recognizable music. It was.
I have never had a speaker do that. What could be the cause? Is it reasonable to assume I can have a problem with the XO with killed the woofer?
Any ideas for next steps, aside from taking it out?
 

ttocs

Well-known member
MLO Supporter
Joined
Aug 10, 2014
Messages
487
Reaction score
125
Location
Highland Park, IL
Well. I proceeded with the dissection. Took out the bottom and went in to look. Everything looked perfect, no loose cables, no oxide, nothing out of place. Clean and shinny.
Disconected the XO from the speaker and connected the speaker cable from the amp directly to the woofer, bypassing all the circuitry. Just got a very very VERY faint sound on the speaker. Had to put my ear on it to determine if it was recognizable music. It was.
I have never had a speaker do that. What could be the cause? Is it reasonable to assume I can have a problem with the XO with killed the woofer?
Any ideas for next steps, aside from taking it out?
Since at this point it's an unknown as to the condition of the XO, proceed cautiously. As spkrdctr said, the woofer is fried.

If you can take several photos of the XO and power board to post, top and bottom, we can look for brown, burnt, black areas and parts. Look at the capacitors and look for bulging and deformation.
 
Top