Audio Systems: radio, high pitch, small caps

Question
-------------------------
Followup To
Question -
H tom I have a 92 maxima with a bose am/fm  tape. My problem is my speakers have a motor boating noise . I get it sometimes in the back and sometimes in the front. I have the two rear speakers disconnected. I get a high pitch noise in the left front and the right front seems to work ok. I took one of the back speakers out and put it on a bench, powered it, and it worked all day with no problems. I'm guessing it is the radio and not the speakers. I cant see all the speakers going all at once. Have you ever run across any of these before. Thanks for the help. John
Answer -
John,
You have the classic problem of the Bose amplified speakers. The capacitors on the amp boards are failing/leaking and when this happens the amps may not work at all or sometimes the amps will make a squealing/popping noise in the speakers. If you use a magnifier and take a close up look at the capacitors on the amp boards, I'm sure you will see several of them leaking the electrolytic onto the circuit boards. It's a little time consuming, however with some patience you should be able to replace all the capacitors on all the boards to make the speakers work like new again. You can always purchase four new amp boards at about $85-$90 apiece.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net
Hi tom Thank you so much. How many caps are there on each board ? Have a great holiday. John


Answer
John,
I don't have the amp boards in front of me right now, however the amps have about 6-7 small caps and two larger caps on them. If you are going to rebuild the amp boards yourself make sure to not mix up the front and rear amp boards. You may want to do the front amps first and then the rear amps. the rear amps are designed to put a little more bass boost in the speakers. You should be able to purchase the small caps for less than $1 each and the larger caps for about $3 each.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net