Bose amp repair: A DIY quest

[elwesso]

As of a few days ago my LR bose amp has failed.... It started to pop occasionally, then it just started hissing and screeching.....

I was reading some of the previous posts, and TEXASOIL described how you can replace one of the liquid filled capacitors or something like that... I sent an email to him and Ill report back with that information.....

Basically Im making this thread in attempt to TRY and fix my amp DIY.. He siad the capacitor is about 50c, and if the amp is gonna have to get rebuilt anyway, it seems worth the gamble to me... I dont konw what they do when they rebuild the bose amps, but if I can get it so it sounds decent again Ill be a happy guy......

[nab911]

As long as the cone and coil are torn, unwound then its all elctrical. And i have fixed amps before by just soldering stuff and so on.

[rrack]

Similar problem cept the left front is now DOA on my girl. Dealing with Bose is sort of a pain. I'm planning to call em back later today and see where it gets me. Anyway, I was told the same. Apparently Bose had a bad vendor for the capacitors. They tend to leak. I still need to pull the sucker out and check em. I'm gonna try and fix it b4 I send it in. If they leak or blow you can usually see it. There will be an oily substance all around it. Sometimes causing a ring aroud it. In the old days, I'd hold a flashlight behind the circuit board and you'd see the oily ring. But you MUST replace it with the EXACT capacitor and watch polarity! Hopefully, if it doesn't reach 100 degrees today here in San Antone, I plan to work on it a bit. If by chance you know which capacitor or the rating, please post it.

robert

[elwesso]

I am looking at my amp right now (have it on my desk), and there is this yellow stuff over the 2 capacitors, and over those "coil looking things'. It looks like some sort of sealant that someone slapped on.. Its very sticky and I can pick at it but its hard to get it off.....

The capacitors (the 2 brownish tube looking thigns around the 3 coil things) have some writing on the side....

NICHICON 820μF 16v

Then on the other side it says "PL (M) "

Then again it says "H9347" "105°C"

When my new digicam comes in (w00t!) I will take pictures...

[nab911]

There you go, 820 mewFarads at 16volts. Ive seen that sealent stuff on the coils before but i dont think so on capacitors. Follow all the traces (circuit lines) on the board and look for any broken ones or shorts.

[elwesso]

I decided to take a couple pics with my backup camera... I forgot how good the macro was with this camera..... GOLDEN! I digress

Anyway, here are 2 pics, you can see the yellow stuff I was talking about.....

[elwesso]

Wow those were big, but anyway you can see everything in better detail than I can see with my eyes!

Everything is so close together I cant follow the circuits well at all!

[nab911]

Lol well basicly your lookin for black/yellow fluxish spots where the solder has melted. But do what rrack said and shine a flashlight through the board or across the surface and look for the oil. If its a known problem its definatly worth checking out. How are your soldering skills?

[elwesso]

I shined around briefly and couldnt find any oily residue or anything of the sorts.. Its hard to find bad circuits that are yellow with this yellow crap everywhere!

Ive never really soldered like this before but again if I screw it up, im no worse off than I was before...

[natsoundup]

wes, what year is your car?

[elwesso]

94 almost 95

[nab911]

what month 94?

[elwesso]

5/94 is the MFG date of my Q.....

[Chad91Q45]

I was going to do the capacitor replacement on my bose in my maxima before I decided to just go all aftermarket. I found a site for the maximas that gave an excellent description. I might have it bookmarked on my computer at home (at work right now) and I will post the link later tonight if I do.

All I know, though, is that Bose is awesome for home stereo. I love mine.... but I am never going to keep a bose car system.

[elwesso]

I love bose... Very good sound, but only when it WORKS!!!!!

Id think itd be a lto cheaper for them to use stuff thats comparable to the aftermarket, and much cheaper as wel...

[Chad91Q45]

Yeah, they do sound great for a stock system.... but it is the trouble on having them work. I might have some of my old amps from my maxima still (seems like 3/4 were working great but I was tired of having 1 crappy one)

[elwesso]

If you have a rear amp that still works Id buy up to 2 (have a spare)...

[911/Q45]

After 10 years, it seems like the paper parts of the speakers would be shot. Those get replaced as part of the Bose rebuild.

[DAEDALUS]

I think the overcoating is the protective measure they added to contain any leaks from the (I assume) dielectric. That was their fix for the fires that led to the recall. You have to chip it out of your way and then unsolder the items from the board. Ask around whereever you buy your new capacitors from--they might be able to recommend a spray or brush-on overcoating if you want to replace it.

mewFarad?

[Chad91Q45]

I will have to check. I know my RR one was the one that was sounding like crap... seems like the RL was a good one along with both fronts.... but I am not positive.

[Chad91Q45]

To me it just seems more right to have Infinity in my Infiniti. Just need to get rid of that blasted Alpine deck...

[elwesso]

Just be careful where you place your "Y's"

[Chad91Q45]

No worries there.

[Jesda]

Nissans/Infinitis/Hondas all have more or less the same amp -- its direct plug and play intercompatibility with (so I'm told) equalization differences.

HOWEVER, the Bose amp from a Mazda Milennia seems to have this oily coating on it aside from just the goo, and this seems to resist amp failures in humid or damp conditions, situations where my Infiniti and Nissan amps often failed.

-Jesda

[natsoundup]

Wes, if your repair doesn't work, I will help you out.

I like reading your stuff on this thread. You have been a big help to many here.

[elwesso]

I got an email from TEXASOIL... and he should be chiming in here soon...

He said that if the capacitors failed then there should be leakage, which I dont have

[rrack]

Well, I got mine apart too. Looks the same. I've checked everything out and everything visually looks good. No apparent leaking capacitors and joints look good. Surprisingly, the speaker cone looks brand new! From there, I called Bose. The automated line says to send them to Clarion for replacement for $120 each???? I thought it was $75 or even FREE. I'm gonna call back and try to speak with a human...

robert

[rrack]

...ok...I resoldered every joint and it didn't change anything. I still have that whistling/buzzing sound with hardly no volume. It sounds like a blown speaker but i know it isn't. Anyhow, I called Bose again. I could never find a human. I left a message for them to call me back (yeah right)...I then called Clarion. They told me that they only exchange the sets for $140 each and have nothing to do with Bose? Why is everything soooooo difficult? I'm willing to pay the $75 bones that I read about but now $120 or $140 each?

Maybe I'll get lucky and somebody will actually call me back and get this solved. Soon I hope cuz my son (6 weeks old) can't live without his Greenday...

[ddrumman]

"I love bose... Very good sound, but only when it WORKS!!!!!"

Wes,I'd have to disagree with you. I would say decent sound and overpriced when it WORKS. Eclipse and Alpine higher end models blow Bose away. Not even close.

D.

[ddrumman]

Also , I know I've posted this here before, and I don't know if you'd be interested but here is a link about repairing bose stuff. Maybe you can get some helpful info for your DIY project.

http://www.carstereohelp.com/

D.