Rear Speaker Problems
Thread Starter
Intermediate
Joined: Jan 2008
Posts: 29
Likes: 0
From: Petersburg Virginia
Rear Speaker Problems
I have a 90 Coupe and I am getting this ungodly squeal from the rear speakers is it possible to un hook them until I can afford to find out what the problem is the front speakers sound superb. The system is a Bose Gold with Cd player any help would be greatly appreciated.
Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
Probably the electrolytic capacitors going bad
The problem you are experiencing is very common.
It is best to disconnect the speakers/amplifiers until it is fixed, because leaving them connected while oscillating may cause more components to fail.
The solution to this problem is usually to replace (shotgun approach) about 7 of the electrolytic capacitors on each amplifier board.
Here is some detailed information:
http://www.zr1netregistry.com/Bose2.pdf
I've repaired about 5 amps with the same problem by simply replacing all those capacitors on each amp.
I just did two from a '91 about two weeks ago.
Tom Piper
It is best to disconnect the speakers/amplifiers until it is fixed, because leaving them connected while oscillating may cause more components to fail.
The solution to this problem is usually to replace (shotgun approach) about 7 of the electrolytic capacitors on each amplifier board.
Here is some detailed information:
http://www.zr1netregistry.com/Bose2.pdf
I've repaired about 5 amps with the same problem by simply replacing all those capacitors on each amp.
I just did two from a '91 about two weeks ago.
Tom Piper
Safety Car
Joined: Jan 2006
Posts: 3,566
Likes: 4
From: Mt Laurel NJ
St. Jude Donor '06-'07
I have a 90 Coupe and I am getting this ungodly squeal from the rear speakers is it possible to un hook them until I can afford to find out what the problem is the front speakers sound superb. The system is a Bose Gold with Cd player any help would be greatly appreciated.
http://forums.corvetteforum.com/showthread.php?t=941281
Good luck, let us know how you make out.
Randy
BTW, my car did the same thing before I replaced everything.
Last edited by RandyJ75; Feb 12, 2008 at 11:16 PM.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
So I have spent lots of time on the internet and in the Forum and put together some info from my experience and research. The three best links are; and the first being the best with most detail.
http://www.zr1netregistry.com/Bose2.pdf
https://www.corvetteforum.com/techti...D=91&TopicID=2
https://www.corvetteforum.com/techti...D=58&TopicID=2
You can find more info using Bose or schematics as key words to search in the Forum but this I think is some of the best information. (You will need to look at the links to follow me).
My particular journey started when I had popping in my right rear speaker. I followed the instructions and replaced all 8 capacitors. Analyzed some of the circuitry to sort it out. Realized that speaker now sounded much better than the one that had no problem (the left rear). So I removed the speaker assembly and repaired the amplifier. Did not have C19 and C25 which are the ones that are a pain to physically install and decided to leave them alone since I felt like they were OK. Reinstalled the unit and had much more base and volume out of the speaker. The point is just because it does not pop, squeak or squeal does not mean that it is working properly after 12 years.
For those are interested, C31 gave me the pop and C172 will cause the poor sound quality. C7 & C8 will cause a worling squealing sound. Most of these are decoupling capacitors and don’t really carry any signal except C172. Capacitors really have to go bad and change value radically to cause a ill effect (most of the time and depending…..). Actually my C7 & C8 both measured about 47 umfd. Out of the 3 – 10 umfd & 4.7 umfd per board, 6 of the 8 capacitors did not measure anything as read on a capacitance meter (not ohm meter). So these 6 really went south, but I have better sound now.
http://www.zr1netregistry.com/Bose2.pdf
https://www.corvetteforum.com/techti...D=91&TopicID=2
https://www.corvetteforum.com/techti...D=58&TopicID=2
You can find more info using Bose or schematics as key words to search in the Forum but this I think is some of the best information. (You will need to look at the links to follow me).
My particular journey started when I had popping in my right rear speaker. I followed the instructions and replaced all 8 capacitors. Analyzed some of the circuitry to sort it out. Realized that speaker now sounded much better than the one that had no problem (the left rear). So I removed the speaker assembly and repaired the amplifier. Did not have C19 and C25 which are the ones that are a pain to physically install and decided to leave them alone since I felt like they were OK. Reinstalled the unit and had much more base and volume out of the speaker. The point is just because it does not pop, squeak or squeal does not mean that it is working properly after 12 years.
For those are interested, C31 gave me the pop and C172 will cause the poor sound quality. C7 & C8 will cause a worling squealing sound. Most of these are decoupling capacitors and don’t really carry any signal except C172. Capacitors really have to go bad and change value radically to cause a ill effect (most of the time and depending…..). Actually my C7 & C8 both measured about 47 umfd. Out of the 3 – 10 umfd & 4.7 umfd per board, 6 of the 8 capacitors did not measure anything as read on a capacitance meter (not ohm meter). So these 6 really went south, but I have better sound now.
