Paging Eagle85C4--Whats' wrong with this picture? Bose.

[Moonunit 451]

OK, I'm making a real effort on this Bose but I'm not having a hell of a lot of luck. I had two dead front speakers and one missing rear one. I purchased the three from a guy off Ebay in two separate offline transactions at a heafty price. One of the fronts was dead, he will replace. The rear has a buzz in it. I have reread the posts on repair and spoke briefly with Dr Don's. The links mentioned on attibi.com are not there.

I'm too far in to back out nowand I can hear reasonable potential from the system if it's fully operational. I'm going to buy a complete system with about 2 yrs original usage, been stored since, for $175. I'm planning on repairing (or maybe sending you) the speakers I currently have.

Here are my questions. I took apart the original speaker that I replaced from my front pass. side. It doesn't look bad to me. Does the photo her or the linked photo indicate bad "caps"? The circuit board looks clean and intact on both sides. Dr. Don mentioned something about the neccesity to acid wash the circuit boards to get corrosion off. I don't see any sign of that on this board whatso ever. Is there a spray or cleaner I should use? Is there a way out of the vehicle for me to test the amps? The links are to additional photos. Thanks for any help you can offer.

http://forus.com/moonunit/Corvette/DSC01004.jpg
http://forus.com/moonunit/Corvette/DSC01005.jpg
http://forus.com/moonunit/Corvette/DSC01007.jpg
http://forus.com/moonunit/Corvette/DSC01008.jpg
http://forus.com/moonunit/Corvette/DSC01011.jpg

 

[Eagle85C4]

Nice pictures...but unfortunatly not one bit of help. The usual problems with the speakers are the capacitors. As you can see there are several types...usually you can test them in circuit, but most of the time it is necessary to remove them then test. For the dead ones it is usually a cap that has an internal short in the power section that does not allow the amp to power up. The buzz is usually a cap in the amp section doing the same thing or instead of a short it is open. Caps normally function as either a storage device for voltage or in the situation of an amp it is used as a filter, in which it takes unwanted frequencies and removes them by sending them to ground. In the instance of the buzz, the cap is failing to isolate the frequencies that cause the buzz and send them to ground. If you are curious enough to try the repair yourself, take a trip to Radio Shack and buy a Digital Multimeter with capacitor testing capabilities and a soldering iron to remove the parts and replace the good ones. For the most part you can get replacement parts from Radio Shack.
In some isolated situations the power amps, the four three legged black chips near where the wires come into the board will go bad and cause similar problems. As well as the 2 intergrated circuits with the bose lable on them.
If not email me and we can discuss sending them to me for repair and a considerable savings. Good Luck...

 

[Moonunit 451]

Thanks Eagle85C4,

Sounds way over my head. I'll email you when I get everything situated. You . I thought from what I had read before that stuff would be melting all over the place pointing a finger at something:eek