Fixed my bose amp ...

dustin · 10 January 2003

I'm sure this is nothing new for all of you but I decided to fix my passenger side bose amp myself. I replaced the amp transistors and all the caps on the board:

After:

This time I used thermal grease to insulate the transistors. I bought the new parts from Digikey with the help of this page:
http://www.ojaspatel.com/nsx/ZR1BoseRepair/

The amp seems to work fine now.

Dustin

BostonNSX · 10 January 2003

how much did u spent on the parts?
dpoes the sub woofer amp works the same way?

dustin · 10 January 2003

I spent about $30 on parts but that is enough to fix all 3 amps in a couple cars.

All of the amps are the same repair wise.

Larry Bastanza · 10 January 2003

Dustin,

Nice Job. Gald it worked out for you.

LarryB

D'Ecosse · 11 January 2003

Originally posted by dustin:
..This time I used thermal grease to insulate the transistors.... Dustin

Nice job - congratulations.
Just a quick point though - thermal compound does not "insulate" the transistors - quite the opposite, it is used as a heat conductor to carry heat away from the transistor to the heat-sink upon which it is typically mounted (sometimes it additionally requires a mylar insulator to electrically isolate it from the heatsink); in this case however, there is no heatsink on the fibreglass pcb, so the compound is superfluous.

dustin · 11 January 2003

I didn't mean to use the term insulate, hehe.

Anyways, the point is to get the heat to transfer away from the FETS. Following that picture I applied that grease to the top of outer edge also, where they hit the metal RF shield/heatsink (removed in the picture).

As you can see in the first picture, there are copper squares under each FET to try to draw away heat from them. However I felt that adding the grease would be more effective than dry heat conductance alone.

Acura NsX Pilot · 11 January 2003

is there anyway to add a small brushless dc fan to the amp to aid its cooling ?

midNight Sun Xpress · 14 January 2003

I have problems with two of my amps at the moment. As I have unerstodd, this is not caused by excess heating in the doors, but a combination of door-slamming over the years and low-quality parts on the circuit-boards.
I have been looking for a repair-shop in Europe, but no success so I am going to send them to the US to be repaired at 85-90$ each.

------------------
Have a Honda-experience every day!

Jon
'91 NSX for summer & '97 CR-V for winter

dustin · 14 January 2003

The problem is that electrolytic capacitors only last so long at a given temperature until they internally short out and cause lots of problems.

Erix · 15 January 2003

When i fixed my right amp last Winter I added a piece of aluminium "plate" to each transistor to carry the heat away from the Pcb.
Used thermal grease to transport the heat from the transistors to the aluminiumpiece.
Just have to wait 5-10 years to see if it worked better than before

MidNight Sun Xpress, You can try to talk me into fixing your amp ;-) (must be better to send the amp to Sweden than US for repair)

Erix
[email protected]

[This message has been edited by Erix (edited 15 January 2003).]

[This message has been edited by Erix (edited 15 January 2003).]

CFNSX · 16 January 2003

dustin........my door amp recently failed and I'm interested in trying a repair as well.......can you advise the part numbers and the manufacturer for the amp transistors and capacitors. Also would these same components be used to repair the centre amp? In Canada I can find no one to repair these boards and the only solution is $600.00 per amp at the local Acura Dealer. Thanks

supergreen125 · 16 January 2003

hey dustin....
how far is folsom from newport beach??

can i interest you in a free lunch?

NSX2398 · 18 January 2003

Originally posted by CFNSX:
In Canada I can find no one to repair these boards and the only solution is $600.00 per amp at the local Acura Dealer. Thanks

There are other solutions. Here's one that I think essentially does the capacitor replacement for you. I found them on the net; gave them a try; and was pleased with the results. Mine have worked now for a year in all temps from -32C to +35C http://www.carstereohelp.com/bose.htm

------------------
- Ian
91 Blk/Blk daily driver; 100K+ miles & still going strong

midNight Sun Xpress · 18 January 2003

MidNight Sun Xpress, You can try to talk me into fixing your amp ;-) (must be better to send the amp to Sweden than US for repair)

Thanks for your offer, I'll send you an e-mail.

------------------
Have a Honda-experience every day!

Jon
'91 NSX for summer & '97 CR-V for winter

Edwardo · 23 January 2003

Dustin,

Do we only need to buy capacitors and transistors for this DIY?

Also, is it hard/risky to take off the door panel? I don't want to damage anything in my door panel.

Thanks

Edwardo · 30 January 2003

Dustin,

Could you please tell us the parts you ordered to fix your amp.

Do we just need the capacitors and transistors?

Can we buy these at Fry's electronic store, or do we have to buy them online?

Thanks

dustin · 30 January 2003

Oh sorry I forgot about this thread.

The caps and transistors (fets really) are the only things that may be broken that you can actually replace. You aren't going to be able to source the ICs.

All the parts I bought were listed in http://www.ojaspatel.com/nsx/ZR1BoseRepair/ I bought them all from digikey:

FETs are part # IRFIZ24N–ND

Caps:

1 uF 50V P10312–ND 50V
4.7 uF P10315–ND 50V
10 uF 16V P10316–ND 50V
47 uF 16V P10340–ND 63V
820 uF 16V P10252–ND 16V
1000 uF 16V P10278–ND 25V

But you can just buy replacements for whatever caps you take off the board.

Frys should have the capacitors but you'll have to order the FETs.

[This message has been edited by dustin (edited 30 January 2003).]

D'Ecosse · 1 February 2003

I am repairing a set for one of the 'Prime members in exchange for using the amp/speaker housing as a template for after-market speakers.
I just ordered the parts from Digi-Key:
$40, incl shipping for enough to do 4 amps.
That includes the 1000uF power rail caps and the FET's, although common opinion is these typically don't really fail - at $0.75 ea for the FETs I thought why not just shotgun whole thing, however by replacing all the electrolytic caps & the FET's for <$10 / amp.
Note from the list in the post above not all those caps are required - that covers all the various iterations by different models.

dustin · 1 February 2003

I used all of those caps except for the 1000uF one (nsx amps are 820uF for C19 and C25)

D'Ecosse · 1 February 2003

Did you use the 4.7uF? I'm still digging my way through the rubber potting material all over these!

dustin · 1 February 2003

I did, sorry for the bad handwriting:
http://images.execute.net/index.cgi?cmd=view&id=5253

Edwardo · 2 February 2003

Dustin,

Thanks for the reply. I went to Fry's and radio shack today to see if I could pick the capacitors up there. Radio Shack has a better selection. They did not have the 820uf cap. Also, they had a 47uf but it was only 35 volts as opposed to 63.

It looks like I will have to buy these parts from digikey.com.

Fixed my bose amp ...

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