Removal, Repair and Replacement of OEM Bose Speaker/Amp Units
This page goes over the basics of the Bose stereo system, causes for failure and amplifier replacement procedure.
Authored by Drew on 2000.07.22, Last Updated: 2000.09.21
Disclaimer: Any and all content is solely my opinion and is not the responsibility of anybody else.
Copyright: may be copied as long as credit is given and MUST BE distributed without charge.
Each amp is tuned for the car AND the placement within the car. Amps from other cars cannot be interchanged and have them expect to sound anywhere as good. In my opinion, even close sounding, would be very lucky.
The NSX has an extremely small interior and therefore the bass must be driven to extremes to sound correct. The mids and highs would carry very well and therefore only the bass would have to be boosted high above what would be necessary for a normal car.
This extreme bass boost would cause major heat problems, which leads us to the next point…
While the components of the board are of *quite* high quality, the heat dissipation abilities are below average, if not downright poor.
The RF shield takes some of the heat, but it is not efficient. If you look closely, there are copper pads below each transistor (you may have to hold the board up to a strong light to see them). These pads actually dissipate most of the heat and are a very poor compromise. The transistors are plastic packed and not suited to good heat dissipation and there is no factory applied thermal grease either.
The small caps also "wear out" because they dry out. Components are usually rated in thousands of hours of use. Those caps should function a couple of thousand hours at "normal" temperature. For every increase of 10 C the useful life of the cap is decrease by 1/2, conversely for every decrease of 10 C the useful life is 2x (+20 degrees would be 4x, +30 degrees less would be 8x, etc…). So the smaller caps going bad should be no surprise to anyone.
The round caps are electrolytic, the yellow caps are film, the round bulbous orange one is tantalum.
RF Shield: Front 137637- 2205, PCB sticker - 112 2205, P/N Date on back 136898 1091
RF Shield: Rear 137637-2206, PCB sticker - 111 2206, P/N Date on back 136898 0491
Each amp made differently and will put out different signals based on several things: placement, speaker size, enclosure size and power.
You CANNOT mix’n match Bose amps on a gross scale. There is something called On-Board Equalization, which means the soldered components on the board create the desired tuning. To make matters worse the door amps have six  pins, while the foot well speaker amp has seven  pins.
While the basic design is the same in almost all cars, the tuning is quite different. To make the sound accurate again, you must compare the boards and swap out the component differences….this includes the underside surface mount components. A very difficult task indeed.
Most cars have much more interior space and therefore the mids and highs are emphasized and bass is not. This will not work with the NSX…it will sound either dry or quite irritating (like all the treble is turned up on your home stereo).
All Bose amps will eventually fail due to inability to dissipate heat. The louder you listen to the stereo the faster they will fail, it is a function of a square (twice as loud = 4x rate of failure).
Allegedly the problem with the NSX amps were solved in the1996 model year (but I really doubt it). Bose changed capacitor makers in `93 and have not had as many problems since.
Infiniti has a long standing replacement policy on their Bose amps, because they are mounted on top of the gasoline tank. They fry or get too hot and they will replace them for you. No other car maker will do this outside of the warranty.
On 2000.09.19 Honda of Japan has recalled 556,924 passenger cars in Japan covering the model years from 1991 to 1997 as they "may heat up excessively and cause speakers to catch fire." There are no plans for Honda of America, per an internal notice dated 2000.09.20, that "American Honda has no complaints of this type in the US market; therefore, the US is not affected by this recall."
Option I Third Party Replacement
For about $250 you can get replacement amps (not made by Bose) from Amp Options (e-mail at: email@example.com or call between 8:00 AM to 9:00 PM EST at 770.638.0359) Has better warranty than Bose, might be better made; apparently not NSX specific at this time.
One site that sells these particular amps for $70 apiece. They say they have been selling them for 4 years and have not had a failure. If you have any more questions please feel free to e-mail or phone me 517.790.2949. ask for Michael. http://mnrelectronics.com/ampoprepbost.html
Option II Have Bose Fix them for you!
Pay Bose. They have tuned each amp to fit the car and its enclosure. For the original stock sound it is better to have the amps rebuilt than to replace them with different part numbers, but the fix may not last very long. Send the entire enclosure (along with a $75 money order) back to them to get them rebuilt. BOSE 800.231.2673.
125 Fisher Street
Attn: John Villa - OEM QA
Westboro, MA 01581
Success is mixed from the people who use the repair option. Many have had the amp fail within months of the repair operation. The only components replaced are those that have currently failed. Components that have not yet failed (or about to fail) are not replaced, possibly sending you back a tired amp.
Option III Repair them yourself
Those style of amps are used in just about every type of Bose install for the past 15 or years. So any car new car can be robbed of parts to fix the NSX amps. Looking at the transistors, two of them are made by IR and have Bose's generic part number: 137110. This part number does not exist and appears (high confidence) to be a relabeled IR's FIZ24 transistor.
Here is a link to the FIZ24 matches on IR
Here is the particular part number they recommend (requires free Adobe Acrobat Reader)
Digikey sells these for $1 each.
The transistor IC replaced was Q1.
The caps replaced in a sample Bose repaired amp were: C110*, C130*, C16*, C183, C172, C203*, C31, C7, C8, C25, and C19.
Note that the ones with a * were replaced with what appear to be tantalum capacitors instead of the usual electrolytic caps. I recommend all caps be replaced with tantalums, if at all possible.
Option of Last Resort Honda Dealership
Purchase replacement speaker enclosures from the Dealer. They apparently run about $950 per enclosure.
Door Speaker Passenger or Driver side
Speaker Removal and Repair
You have now exposed the black plastic speaker enclosure assembly. The actual speakers are 6-inch diameter, 1-ohm impedance and fastened at only three points. You should not have to remove the speaker at anytime during this procedure.
Passenger foot well bass speaker, passenger floor pan
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