amitanjana

Hi all

My first post here, so please excuse me if this has been beaten to
death before. I could not find any answers to my question in archives.

All of my Bose amps are dead, and I wanted to get them repaired. Any
DIYers out there who tried it? I heard that the capacitors are the
ones that go bad, and replacing them fixes the problems. True, or is
it more complicated than that? I have taken all four amps out and
they look OK cosmetically.

Replacing the system is not an option because I just put in a new
indash Bose CD changer (or is it?).

Thanks for looking at this post.

--amit
(Amit Mathur)

klymkow

Strange that all 4 would go dead. Did you check the relay the for Bose amps first (front left kick panel area)? Sounds like this might be bad if the amps are not turning on. Check to see if power (12v)is reaching the amps - easy at the rear speakers.

Usually the capacitors going bad will result in a squealing type of sound from the speakers. At first it may go away after a few minutes, then just keep getting worse and eventually squeal all the time. The amps would still pump out the music however.

I've used Elliott Electronics - $75 each including return shipping. I don't know which caps go bad. Could always replace all of them!

Tim

amitanjana

Actually, they have been going bad one by one. The front passenger side still works, but I have started hearing squealing occasionally
recently. The others started squealing, but have since either gone dead, or produce too much squealing for my ear. I will try replacing
all capacitors on the board first before sending them out. I just wanted to know if there are any other known problems.

Thanks for replying.

--amit

chchmax

yes, it is usually the capacitors that go bad.
try this link..
http://forums.maxima.org/showthread...&threadid=50398

i've replaced the capacitors in mine, and they're like new!

Heres the relavent part:
Posted by AC439


Quoted Message:
--------------------------------------------------------------------------------
2) BOSE AMP: When I first bought the car used, the front drv BOSE speaker was low on volume. I didn't quite know what's going on so I yank it out and found an amp inside. Without a clue where to start so I swap the left and right amp and confirmed the amp was bad. Of course, like most of you, I checked with the dealer and got a quote of $500. I then called around for electronics shops and found one that is willing to repair it for $50. They said Nissan send them amps to fix daily. So I had them repaired it and they gave me a 90 days warranty (it's been 5 years and the amp still works). As time goes by, two other amps started to failed and I took them to the same shop and they raised the price to $75 each. Then the last amp failed. I was wondering what they did to fix my amp so I yanked a good amp out and found they changed only 7 electrolyte capacitors ! The reason is the electrolyte fluid inside the caps will dry up causing them to fail. Other components on the amp are solid states and all sealed. Each of the cap costs $0.05 ! So, I bought the 7 capacitors and replaced them all on the last amp. Sure enough, it works ! So, if you want to keep your BOSE systems and the speakers are going out (actually the amps), you can DIY and fix it for 35 cents ! Again, you will need to operate a soldering iron, which is not difficult. These capacitors have polarity and you have to put the new ones in the exact polarity as the old ones. Below are the capapacitor value:

C16, C203 - 1uF 50v
C7, C8 - 47uF 16v
C183, C172, C? - 10uF 50v

C? is the one next to C203, close to a coil. I can't read the lable on my amp but you won't miss it.
--------------------------------------------------------------------------------



hope this helps.

amitanjana

It does. Thanks.

--amit

Agamemnon

Wow, these are very interesting stuff! I'm hoping this can save me $150! Some questions about them though:

Where do you find these capacitors, besides Radio Shack? My local Radio Shack has 2 of the capacitors, but not one of them (the 47uF 50v)

How easy is it to replace capacitors? I've never done this before. How do you take the old one out, for example? And then how to put the new one in there?

Spipedong90

Check with Mouser Electronics. they usually have most everything.
http://www.mouser.com/

AC439

RadioShack is not always stocking all the different values of the caps, since no one in US wants to get into component level repair. However, you can have them order the caps for you. They have a big catalog and they can surely find the part and order for you. I didn't need to go this route when I was living in another town (which has a retail electronics store).

Replacing them is very easy. You don't need to use a desoldering iron. Of course, it's good to have one. You need to user the iron to melt the solder and use another hand to pull the cap out. The only thing you need to be careful is do it gently or you could pull the circuit track off the board. Also, soldering it back is very easy. Just need to make sure you don't short the circuit with neighbor pins.

amitanjana

How does one get rid of the glue that covers all capacitors?

--amit

gdmaxse

iTrader: (1)

my bose stereo intermittenly cuts off and there is no sound from any of the speakers (usually at startup), there is still power to the head unit because the radio stations still show up on the head.
could this be the amps or capacators?
thanks

AC439

Well, it's up to your creativity to remove it. I use a rasor blade to cut it but you've got to be very careful not to damage other components. I would recommend to have a beer AFTER you have completed the job.

AC439

Maybe, maybe not. I think there is a relay to give power to all 4 amps when the radio is on. My car doesn't have a problem with the relay so I can't tell where it is. But I remember seeing some other posting about check that relay.

Regarding the caps, if they are original, I would recommend replace them. Since they will eventuall fail.

A correction: My last reply about beer should read -> I would NOT recommend to have beer BEFORE you start the job.

Agamemnon

Aren't the glue "hot" glue? Would heating them with a hairdryer or something soften them and makes them easier to remove? Would heating be OK for the rest of the components as well?

BTW, a friend of mine told me of a company that sells all kinds of capacitors and electronic stuff mail order. It's called digikey.com. They have so many kinds of capacitors though, so much that I don't know which one is the correct one anymore! There is such a thing as too many choices!

amitanjana

Well, beer+glue sounds like a good combination!
Actually, I got the glue off by either heating it a little bit,
or pulling it off with a nose plier, and then cutting it.

Some additional information, corrections:
C?? is C31 (not that it helps, because you cannot see the number)
C183, C31 : 10 uF, 16V (not 50V, although 10 uF, 50V does not hurt),
C172 : 1 uF, 50V for rear amps, and 4.7 uF, 35V for front amps

I am not done with all the amps -- just one rear amp is done and it works. I have, however, taken the capacitors off from one front amp, and have looked at the values of C172 from the other two.

Hope that helps anyone else who is trying to do the same thing, and thanks to everybody who helped out.

--amit

P.S. I cannot check my email from work, so if anyone has questions for me, it may take quite some time to reply (am out the coming weekend).

Matt93SE

iTrader: (44)

Good work, gentlemen.. you've earned a spot on the 3rd gen FAQ page.

And yes, digikey is a VERY good resource for electronic parts. It's the place we use at work to order almost all of our components for the prototype sensors and other products we make.

mcmelectronics.com is another place, but they tend to be a general "overstock clearance house" on electronic stuff in general. some very good deals in there on audio equipment, components, etc etc.

AC439

Nice job. Do the rest of the amps. You should be able to do them all in less than 10 mins. Give yourself a pat at the back and forget about Nissan asking $500/speaker.

amitanjana

Sorry, one correction

C172 : 10 uF, 16V for rear amps, and 4.7 uF, 35V for front amps
^^^^^^^^^^

--amit

AC439

Haven't been checking the board for a while. Regarding getting electronics components, I found an on-line store which is very cheap (parts as well as shipping cost). www.futurlec.com, I ordered from them before and I like them. However, the shipping can be slow since they could ship parts from their Asia warehouse. If you can wait, they give the best price and there is no minimun order.

- AC

AlonSeal

Well, I've tried it and it works... except...

I was working on the two rear amps, and one of them now is making a loud buzzing sound whenever the radio is turned on. I've swapped amps to confirm it isn't the speakers.

My nx step is to re-examine the solder points, as well as check for "shorts"...

any other suggestions?

psygnius

Sup, I'm the other n00b on the site.

When I tried to remove the 6 wires on the top of the amp, they don't seem removeable. However, when I see pictures of other similar amps on like eBay and such, they look like they have a simple counterpart connector that plugs right in. Is there anyway to buy the plug piece and then connect them to my current wires?

BTW, I have no experience with a solder gun, so I wouldn't know how to desolder these wires off the amp. I was thinking of buying an amp on eBay, and then buying a connector for it. Then just cut the wires for the amp since I dunno how to desolder these things and using wire strippers to rewire the new amp on. Anyone know if this is possible for the solder and capacitor illiterates?

On another note, at the beginning of the year, I replaced my 1990 Bose receiver with a Bose receiver from a 2000 Infinity that had a CD player. I had to cut all 16 or 17 wires and rewire them to the new connectors. Everything has been running fine and playing perfectly. Except my back speakers aren't loud like they used to be when I first bought the car. I don't know if they were that soft before I made the change. Do you guys think my amps are bad or maybe my receiver had something to do with it?

The 2000 Bose Receiver I put in was also a Clairon Bose, like the old one.

sgoyal

iTrader: (1)

I took my front Pass. Bose speaker out yesterday and removed the circuit board. One of the 4 rectangular components is burnt badly. See below. Has anyone had this problem before, what are these black things called? should I even bother trying to fix it?






Another question: Is the printed circuit board same for all 4 speakers or is it tuned for each location?

Michael

iTrader: (21)

Yup seen it. There was someone else that had that problem on here and I rebuilt a set of amps for someone and he had the same problem. I didnt replace the component because the board was pretty bad but found another front amp and rebuilt that one for him.

The amps are tuned for front and rear but not left to right...in other words you can put a front left speaker in the front right without any sound difference. From what I can tell the board looks to be the same but there are a few component differences from front to rear.

of course all the amps are interchangable but you will not get the right sound if you put a rear amp in the front...but it will work.

sgoyal

iTrader: (1)

Thanks for the reply, do you know which components are different? If I come accross a used board, is there a way to tell the front from the rear?

Michael

iTrader: (21)

I know the caps are different but not sure about what other components are. They should have a sticker on the heat sink (the thin metal that was on there) that says front or rear. If that isnt there then look at your front and rear heat sinks because they are different and you will be able to tell from that.

oh and the sticker may actually say "front" or "rear" or it may just have a f or r on it by some numbers...example-I have 2 rear amps sitting in front of me and one says SIGMA 928 R and the other says SIGMA 928 REAR.

also the amps are different from 89-91 (not sure about the ending date) than the 92-94. The older ones have the wires soldered onto the board and the newer ones do not...they also have different caps if I recall.

sgoyal

iTrader: (1)

The used amp I'm looking at doesn't come with the heatsink, its just the board. From the picture it looks same as mine, ofcourse I don't know about any component values that could be different.


also the amps are different from 89-91 (not sure about the ending date) than the 92-94. The older ones have the wires soldered onto the board and the newer ones do not...they also have different caps if I recall. [/QUOTE]

So the speakers out of a 91' won't fit the wiring connector on my 92' is that correct?

Michael

iTrader: (21)

So the speakers out of a 91' won't fit the wiring connector on my 92' is that correct? [/QUOTE]

speakers are the same but the amps are different. basically there are 2 different amps...not sure the exact years they changed but the 2 types are...the older amps have the connector soldered directly onto the board and there is no plug. The newer amps have a plug soldered onto the board and the wires can be unplugged to take the amp out.

only get the same kind...if yours has the soldered in wires then only use that type of amp and vice versa...beleive me you would be able to tell the difference in the 2.

oh and I havent checked but you could probably use either one but have to match up where the wires go onto the board...example- take the plug off and solder the wires in to the correct place on the board (they are labled v+, grnd. and such) I assume that would work but not 100% sure since I havent tried it and is probably too much trouble anyway.

Giovanni

I got some of the capacitors at RadioShack and they are gigantic compared to the stock ones. There are almost twice the size?
Bigger is better? Will the work fine?

TX

Michael

iTrader: (21)

as long as they are the right value (higher voltage is fine) and will fit under the heatsink then it will work.

emeraldmax

that piece that is burned is called a transistor

Giovanni

I gave up, where is C172 and C183???????
I looked everywhere, took the glue off and nothing.
Why me why me????
The capacitors needs to be non-polarized?
The 10 uF 16V I got it in Tantalum Capacitor, will that work?
Please advise, I want to fix asap.

Btw. I am working on the rear amp.

sgoyal

iTrader: (1)

Look at my post earlier in this thread that shows close up picture of the circuit board. Both the CAPs you're looking for are next to one of the Bose ICs (integrated chip). Just in case you don't know, ICs are the long black things that looks like caterpillars.

Giovanni

1st IC is C162, C160, C9, C120 etc.


I cannot find C172 and C183. I looked all over and nothing. I have an 89 SE.

Help Help Help

Giovanni

Okay, I see now. We have different amps.
Anyone fixed their 89 amps????

bbmax

I also am facing the problem where my bose amps gone bad...
but i'm too lazy to look and finding capacitors...

can't you just purchase bose stereo system from '92~94 model and place it into 89 model??
Anyone done that here??
And how much did you pay for the stereo system??

Giovanni

I will let you know next week.
I purchased front speaker assembly on this forum from a 1992 maxima.

Michael

iTrader: (21)

its a different plug so number one you will need to go to a wrecked car and get the right plug. Then hope the wire color codes match when you are splicing them in.

I know for a fact that the plug for the 89 will not work on a 92 speaker pod without changing the plug. I am talking about the big plug that goes into the unit etself. There are also differences on the amp board itself. The 89 has the wires soldered onto the board and the 92-94 has a plug.

LegitMafiaBoss

Is it worth it to replace the transistor? Or even possible for someone without a Electrical Engineering Degree?

chchmax

definately! its still a lot cheaper than paying to have the amp repaired. If you can use a soldering iron, you should be able to manage it, otherwise i'd leave it to someone who can.. goodluck!

Giovanni

I bought a '91 front speaker assembly and it fits perfectly in my '89.
The plug design is almost the same, you just modify the plug a little bit by cutting a piece of it.

scottdawg

After experiencing the same problems that are listed above, I am now going to try to repair my bose amps.

Do you think the only parts that went bad in my amp are the capapacitors?