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BOSE Amp Capacitor Replacement

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Old 09-15-2014, 08:13 PM
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LannyL81
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Default BOSE Amp Capacitor Replacement

I decided to replace the caps on the four BOSE amps within my '96 CE; no idea if they are original amps or not.???

ANYWAYS......I ordered caps from DigiKey using a list I found here on the Forum only to find-out that it was not for my '96...so I have a few extra caps that I do not need, but I am also missing one.

There is a single 22uF cap, labeled C203 on the rear boards; anyone happen to know what the function of this cap is? I have some 47uF caps that I could substitue, but not knowing this cap's function makes me think best if I just go get some 22uF.

Would still like to know what C203 does in the circuit. I have searched and found several schematics and threads, but none match this amp, all seem to be for earlier year

So if anyone happens to know of a really good link for BOSE amp information, sure appreaciate sending it my way.
Old 09-15-2014, 09:29 PM
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fl_799
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Lanny, It gets worse for the earlier cars too. I was in the same boat when I redid the Bose amps and tape deck in my '89. Painfully short of any information and/or schematics outside of a few sites you've probably already found.

Best bet is to continue what you are doing, grab the correct values and swap the electrolytic caps out with the same values. They will work like new when you are done. I'm a DIY guy by nature so sending them out was not even a question.

James
Old 09-15-2014, 11:41 PM
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RUU
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Originally Posted by LannyL81
So if anyone happens to know of a really good link for BOSE amp information, sure appreaciate sending it my way.
I'm thinking of doing the amps in my '96 this winter.
Old 09-16-2014, 12:06 AM
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mike100
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I can't find the original source of this schematic, but it appeared on the ZR-1 registry at some point. C203 is a noise filter for one of the amplifier IC's, but not really part of the circuit that handles the analog signal. I would probably leave it alone and try it with the other caps replaced. Additionally, some of the better Fluke handheld meters have a surprisingly accurate capacitor check feature. (you may have to unsolder and remove it from the circuit to get a reading though).


Old 09-16-2014, 07:53 AM
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LannyL81
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Yeah...guess I will just go get some 22uF caps instead of seeing what a 47uF cap does.

RUU: I will send you a list of the caps you will need for your amps so you do not get caps that you do not need and missing others. I have not taken the front ones out yet in order to see what caps I need for them; it will be a few days before I send the list to you.

NEW PROBLEM: I broke one of the ceramic caps while removing the potting material....AAARRRGGGHHHH!!!!
Going to try calling a couple of the BOSE amp repairs shops I have found on the 'net to see if they will sell me one ceramic cap. If not, then I may have to send it in for repair or obtain a replacement.

RUU: lesson learned.....be CAREFUL in removing the potting material!!!

AAARRRGGGHHHHH!!!!!!!
Old 09-16-2014, 11:33 AM
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mike100
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I have a couple of parts amps- which one do you want? Also see the threads on the Nissan junkyard Bose amps- they are newer improved versions of the same amp with good capacitors that last much longer. I bought several of them from the wrecking yards for $8-$10 each. It was just so much easier.
Old 09-16-2014, 04:33 PM
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mike100
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UPDATE:
I found the original link in the tech section (from 2006). There's good write-ups and the source of the schematic in the links in the first post.
https://www.corvetteforum.com/forums...-and-more.html

I also had a comment that C203 does make a difference (if it is bad) as it does filter noise from the ground connection to the op-amp IC's.
Old 09-16-2014, 05:15 PM
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mike100: I need one of the small square, off-white color capacitor; has .27 J 63 on the top edge of it.
Not all Bose amps used in the Corvettes have these capacitors and I do not know what year the amps came-out with these capacitors on them.

The caps are shown in this picture:

Last edited by LannyL81; 09-16-2014 at 05:26 PM.
Old 09-16-2014, 09:59 PM
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I have an original Corvette amp (that squeals) with that very cap in the C111 spot. I'm probably not going to fix this particular amp so I will warm up our soldering machine and de-solder this tomorrow. PM me a shipping address and you owe me a stamp, lol.

I have yet to see one of these amps with that blue trim pot.
Old 09-18-2014, 05:08 PM
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LannyL81
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mike100:You are not going to believe this...I know I sure do not; I took out one of the front amps and began working on removing the potting and guess what I broke? Yep...$%*!*%@....another one of those caps. And to top it off....the same value, .27 J 63, just in a different location.

Any chance you still have that soldering iron of yours warmed-up and could remove one more cap for me?

I am going to have to pay you something for two of these and all your effort.

Let me know.

LannyL81
Old 09-18-2014, 08:42 PM
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I only have one parts amp as i tossed a few others during an office move (i was keeping them at work). I have no more. They are a .27uf capacitor- probably 25v rated. you can buy some generic replacement.

Quite honestly though- you seen the posts about the $10 (or less) Nissan Bose amplifiers haven't you? That's why I tossed my parts ones- way less time to pluck a couple from the wrecking yard.
Old 09-19-2014, 08:30 AM
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Hey no problem....just thought I would ask. I hope the .27 J 63 on the cap stands for .27uF and is not some type of coding where a "secrect decoding ring" is needed.

Rad about the Infinit I30 and Nissan Maximas Bose amps being the same and might take the time to head over to my local U Pull It and see if they have any. May also check out the local scrap yards and see what I find.

I had to order additional 10uF caps so I included some .27uF caps as well, hope they correct.

Thanks again for sending me the one you have, can't say how much I appreciate it.
Old 09-19-2014, 07:44 PM
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I took the easy route of going to the junkyard and getting amps out of late 90's Infiniti I30's. I replaced all four and got a spare front and back amp for $60. I changed all four out in about an hour.

Supposedly the ones for them are of better build quality than the ones GM got. Don't know if it's true but two of my Vette's had failed and all the ones from the junkyard worked.
Old 09-19-2014, 08:54 PM
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Originally Posted by Cool95vette
I took the easy route of going to the junkyard and getting amps out of late 90's Infiniti I30's. I replaced all four and got a spare front and back amp for $60. I changed all four out in about an hour.

Supposedly the ones for them are of better build quality than the ones GM got. Don't know if it's true but two of my Vette's had failed and all the ones from the junkyard worked.
It really depends on the age and condition of the electrolytic caps on the board. They get old and dry up. 20 years is about the best one could expect although I have a Moog synth from '81 and the originals caps were just recently replaced this year.
Old 09-20-2014, 07:51 PM
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All caps have been replaced...including the two I broke....got the rears installed, but not the fronts yet. Found that both front speaker housing forward mounting areas were broken. I have never taken these out and from the gooey stuff on the top edge of both front speakers, I doubt that these have ever been removed since installed at the factory.

So I have JB Weld the cracks and put a stiffner on the back side....waiting for the glue to dry.
Old 09-20-2014, 10:17 PM
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Originally Posted by LannyL81
I decided to replace the caps on the four BOSE amps within my '96 CE; no idea if they are original amps or not.???

ANYWAYS......I ordered caps from DigiKey using a list I found here on the Forum only to find-out that it was not for my '96...so I have a few extra caps that I do not need, but I am also missing one.

There is a single 22uF cap, labeled C203 on the rear boards; anyone happen to know what the function of this cap is? I have some 47uF caps that I could substitue, but not knowing this cap's function makes me think best if I just go get some 22uF.

Would still like to know what C203 does in the circuit. I have searched and found several schematics and threads, but none match this amp, all seem to be for earlier year

So if anyone happens to know of a really good link for BOSE amp information, sure appreaciate sending it my way.
I wrote this link many years ago and I think it might answer some of your questions. I have repaired many amps and never really found C 19 & 25 to be bad.

https://www.corvetteforum.com/forums...-and-more.html

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