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93 C4 Bose Amp Repair-How To/Results

2VettesMike

Well-known member
Joined
Sep 27, 2006
Messages
131
Location
Blk Mtn, NC
Corvette
1972 Bryar Blue Coupe 1993 40th Coupe
OK I know I am not the first one to tackle C4 Bose Amp repairs from the "scratchy, poor sound, squealing, etc." problems. I thought those interested may want a first hand updated report.

Over the weekend I pulled out the rear amps. Total time to remove about 10 minutes each.

Since we are talking about amps averaging 20 years old take if from this recovering technician now working as EE the aluminum electrolytic capacitors have dried out; don't bother troubleshooting them just shotgun the replacements while the board is out.

I ordered all the round electrolytic capacitors (see Gary James' excellent writeup at the link below for parts/location diagram) from Digi-Key for all 4 amps, about $32 including shipping.

First amp took a little longer than the second of course to repair. Estimated it took about an hour per amp board to change out all 9 front amp/10 rear amp capacitors.

No offense to anyone's electronic skills but I would rate this a 8 out of 10 on the difficulty scale. (Translation if you don't have a vacuum solder tool and experience working around small pc board traces, holes and surface mount devices find someone to do it for you)

Result: Both rear speakers working like new and front ones go under the solder knife this week.

courtesy of Gary James @ZR1 Net Registry
http://www.zr1netregistry.com/Portals/0/Bose2.pdf

Best of luck,

Mike
 

BillyDee

New member
Joined
Aug 12, 2013
Messages
2
Location
indiana
Corvette
1990 corvette convertible
To be quite honest with you i tackled the blose system also but i went into the new technology era cause the bose might work tomorrow or might not.spend your money wisely on a new aftermarket system that will last alot longer and prolly more enjoyable over the factory 20 plus year old system.Just my 2 cents.
 

2VettesMike

Well-known member
Joined
Sep 27, 2006
Messages
131
Location
Blk Mtn, NC
Corvette
1972 Bryar Blue Coupe 1993 40th Coupe
For those of you who may be thinking of doing this repair I can save you a little time on ordering. Below was my order to Digikey for the capacitors.

This parts list is valid only for the Coupe.
To use on the convertible you will need to add 4 more of the P15830CT-ND for the C110 location on each amp.

Thanks,

Mike

Index
Quantity
Part Number
Description
Customer Reference
Unit Price
Extended Price
1
12
P15786CT-ND
CAP ALUM 10UF 16V 20% RADIAL
C183, C172, C31
0.276
$3.31
2
6
P15830CT-ND
CAP ALUM 1.0UF 50V 20% RADIAL
C16, C150
0.35
$2.10
3
4
P15758CT-ND
CAP ALUM 4.7UF 50V 20% RADIAL
C203
0.63
$2.52
4
8
P15794CT-ND
CAP ALUM 47UF 16V 20% RADIAL
C7, C8
0.48
$3.84
5
8
493-3115-ND
CAP ALUM 820UF 16V 20% RADIAL
C19, C25
1.85
$14.80
Subtotal
$26.57
 

Hib Halverson

Technical Writer for Internet & Print Media
Joined
Jan 10, 2001
Messages
13,453
Location
CenCoast CA
Corvette
71 04 12 19
To be quite honest with you i tackled the blose system also but i went into the new technology era cause the bose might work tomorrow or might not.spend your money wisely on a new aftermarket system that will last alot longer and prolly more enjoyable over the factory 20 plus year old system.Just my 2 cents.

The problem is that aftermarket speakers do not easily adapt to either the Bose amps or to the OE radio head.

Also, the fact is the stock Bose amps and speakers, especially those in later years which had 50 watts each (total of 200W), provide pretty good sound. Their weakness is those electrolytic capacitors.

A good compromise is new or repaired Bose amp/speaker units paired with an aftermarket receiver. Zip Products sells conversion kits to put either a Pioneer or a Kenwood receiver in a C4 along with adapter harnesses to connect to the Bose amps.

That's what I put in my 95 and the difference was huge. Better sound plus I can connect an iPod to the system now, too.

For more info:

C4 Corvette Sound System Upgrade: Part 1

C4 Corvette Sound System Upgrade: Part 2
 

Rob

Site Administrator
Staff member
Administrator
Joined
Sep 16, 2000
Messages
13,864
Location
New Hampshire
Corvette
1990 Corvette ZR-1
You can also ship them back to Bose and they will rebuild them for you.

Sent from my SCH-I535 using Tapatalk 2
 

sweabe

Well-known member
Joined
Aug 31, 2008
Messages
94
Location
Stockholm, Sweden
Corvette
1994 Torch Red Conv
Is this valid for a -94 as well?

sweabe
 

2VettesMike

Well-known member
Joined
Sep 27, 2006
Messages
131
Location
Blk Mtn, NC
Corvette
1972 Bryar Blue Coupe 1993 40th Coupe
Sweabe,

From what I can see in my OP attachment it works for 91-96 models. The 90 model board used slightly different values for the large capacitors. Good luck.

Rob,

You are right for those they may not be comfortable or have access with the capacitors replacement option. In my case $32 vs. $400 for 4 amps rebuild was a no-brainer.

I spent too many years as a technician before getting into the engineers' chair....

Take care.

Mike
 

sweabe

Well-known member
Joined
Aug 31, 2008
Messages
94
Location
Stockholm, Sweden
Corvette
1994 Torch Red Conv
Thanks, my -94 does not have this issue yet, but you never knows when it occurs.

sweabe
 

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