'93 Coupe, 102K:
1) 6 months ago, started eating CD's. Got fixed 5 months ago by Same Day Auto Audio who did great job. While head unit was out of car, also did badgerjim's speaker cone fix. Put it all together and it sounded great.
2) About 3 months ago, started to get the dreaded pop/hiss effect. Hardly any static when car was stationary -- there was more when moving, and sometimes even more when hitting bumps. Not completely sensitive to volume control -- signal got louder at a higher rate than the static. Still could play music very loud and clear. Didn't matter if it was tape, CD or radio. Did a search, posted as well. Consensus was amps were dying.
3) Got busy in work and talk shows were "OK" (car is a DD). If I played CDs very loud it was pretty much OK also, except during quiet parts
4) Had some time two weeks ago and ordered new amps from Bose. They arrived today. I was pumped.
5) Installed them and NO IMPROVEMENT!!! Still sounds good except for the random hiss/pop/static/whatever

So,
a) There will be a set of old (but apparently still good) amps for sale cheap in the C4 parts section
b) ANY IDEAS AS TO WHAT I SHOULD CHECK/FIX NEXT? (please no "junk the Bose" stuff -- I've read enough and it really does sound good until the "snap-crackle-pop" occurs)

Thanks!

 

it sounds like the receiver is out of wack. It is the brain box (either under the dash or in the left rear bin) that controls both the head unit and the speakers. It is the signal source and the output source. In short, the head is a dummy display unit. Nothing more, nothing less. It sends a signal to the receiver module, and that in turn sends a signal to the speakers. In turn, the module receives the FM signal and then sends that to the speakers. All the head does is give control commands.

here in lies the other problem. The replacement bose amps are generic, and not specific to the car. This means the custom equalizations are not right.

I know a lot of folks who want to keep the bose, that's fine... but I am one who hates the POS.

It has muddy mid-bass responce, no sub at all and the highs are flat as hell. From an audiophile perspective, Bose literally Blows.

I have not heard a Bose system that truly impresses. I guess the old 904s are ok, but that's about it.

The other issue is a lack of expandibility. The C4 systems cannot accept a CD changer or any other input, other than RF. updating components on it isn't going help, either.

 

Thanks, Andy -- I have read some items (including one of the Ebay repair vendors) which suggested the symptoms might relate to the receiver. I was hoping not. It's a PITA to access and switch out, correct? (not to mention another $XX to repair or replace.)

 

you're welcome!

well, for your year, I don't know where the hell they put it!!!

1993 SHOULD be behind the dash... it's not THAT bad to reach. Remove the glove box and you're there.

 

Used ones are usually in the $25-75 range, although they don't come up here all that often. If you post a WTB somebody will have one.

There are usually one or two on ebay in that price range as well.

 

Could also use a line-level switch.

 

those adaptors introduce more noise than anything else.

a friend has a 92 vert, and the prior owner monkeyed with the bose. put a POS pioneer amp on it. it sounded like music played through speakers made of mud... ugh.

 

I suspect you are referring to an adapter for the bose-level signal coming out of the CDM, not an input line-level switch for the signal going into the CDM, which is what I was referring to, in response to your statement that RF is the only way to add an external signal.

If you are actually referring to a line-level switch, then if you have one that introduces noise, it is a poorly built example.



I found that running the Bose CDM output into an aftermarket amp works perfectly well, but not all aftermarket amps will be able to handle the very low level input signal.

 

Do you get the popping in both radio and CD operation? If you had an amp bad , most likely, they would not all go at one time , so you listen up close to each to speaker to hear which amp is bad, Most likely it is AGAIN your head unit or less likely the radio module behind the passenger seat. I had Same Day Service fix a couple of different things for me and they did it for a great price - the repairs only lasted months then went bad again, I started using Doctor Dons again and have not had that issue.

 

Thanks! -- I agree that all the speakers popping made me doubt the amps but as old as they were I went with the "obvious" fix. Oh, and it happens on radio, tape or CD -- but is worse with weaker radio stations. Thank goodness on the '93 the radio module is accessable. Probably will do that next as it is not too pricy. Interesting you mention the head unit as I did not think that would be introducing much signal interference but what do I know.......as I have already demonstrated

 

As Bogus already said, FM audio signals do not pass through the HU, so it appears to be your CDM.

 

yea, it's sounding more and more like the CDM.