scdfndr

I own a '93 SC300 in very good condition. I've kept it up nicely, repairing every ding and replacing the interior, twice now. Recently I've had problems with the stereo -- the original nakamichi system. I'm not satisfied with the advice I've gotten thus far at the local car stereo shop.

When the car sits over night and starts up, the stereo sounds fine. But after 30 seconds or so, the entire system sounds muffled and the volume goes down to about half of what it should be. As best I can tell all speakers are affected. When in this state -- muffled sounding -- if I turn it up, the sub in the back vibrates and crackles.

The guy at the shop says the sub is definitely bad. What he cannot tell me is whether the sub is somehow affecting the amp and thus all other speakers, or if all the speakers are bad, or if the amp is bad, independently of the speakers. He says there is no real diagnostic test. All he can do is replace the sub, but if the amp is bad the same problem will recur in short order. Or he can send the amp off to determine if it needs to be repaired. That will cost, I think he said $250, even if only to learn the amp is fine, or beyond repair. I worry what he really is telling me there is no sure way to fix the problem, short of replacing the entire system, something that seems not cost-effective given the age of the car. And of course I want to keep that original N system if possible.

Sorry for the length. Any thoughts?

Thanks.

freakness

Dude,


Unplug the woofer and see what happens. The guy simply doesn't care and just wants/needs easy money.



- good luck

scdfndr

Great. Thanks. I called a guy in Florida who works on these who says he's seen something like it before and that it's "a stereo issue, not an amplifier issue." I'll try what you recommend.

t2d2

iTrader: (8)

This is one big reason why I despise integrated, proprietary audio systems, be it car or home. If something goes wrong, it's so much more difficult to troubleshoot and expensive to replace. Totally separate/unrelated components are the only way to go, IMO. As an added bonus, you almost always get better sound quality at the same price point.

Teal Sc400

First ? Have the (stock) rear speakers been replaced, if not most likely have blown/disintegrated? A similar problem happened to my system some time ago. I did a DIY and replaced my rear speakers fixing the problem causing all my speakers to function. Or it could be a faulty volume/AC control switch module ****.

scdfndr

All original.

Again today, first 30-45 seconds after cranking up car, everything is good. Then all at once everything thing sounds like its underwater.

Teal Sc400

I would say the rears speakers have disintegrated, from the heat//sun these stocks were cheaply made and I'll post up my pictures/DIY/link and u can conduct a test by taking down the liner in the trunk to the speaker + - connections. Here the link its post 9.

https://www.clublexus.com/forums/sc-...o-problem.html

t2d2

iTrader: (8)

I don't see how disintegrated speakers would explain it sounding good when initially powered up.

matguy

Agree with this. And, yes, the car audio shop guy is just going to want to individually change out components 'till your whole system is new. Charging you all the way.

I would imagine something his heating up and failing. Either it heats up to normal operating temp and loses connection, or something heats beyond what it's supposed to run at and disables itself.

Not that this helps you figure out what it is, other than it's unlikely a single speaker doing this to the whole system.

I would start with the amp, since it's fairly easy to get to, and unplug all the harnesses and plug them all back in. If it persists, try with the deck. It's a bit unlikely that it's this, since a good bump would probably make the sound go on and off, but it's one of the easiest tests.

Otherwise, does this only happen with the radio or also when playing CD's, including the CD changer, if it still works. I can't remember which one, but either in the Pioneer or the Nakamichi system cuts the signal if the CD changer is taken out. It's slightly possible the CD changer is even the culprit. Annoying, huh?

So, while I can't argue too much with the idea that integrated audio systems are a pain in a lot of ways, it can be difficult to offer some of the features without integrating some of the components. It's usually at least cheaper for them and they don't care about aftermarket, or even repairs past the warranty.

Really, this one isn't as bad as it could be. I had the Nakamichi system. I have an aftermarket deck that actually fits decently and doesn't look all that bad, but still use the factory amp and all the factory speakers; just added an amp for the sub. That doesn't happen in a lot of cars. Try that in my wife's Volvo with their odd-ball fiber optic digital system. You can use the factory speakers, but you need to replace the deck and amps plus re-wire all the signal wires, some of the speaker wires, and the antenna wire (because the tuner is actually on the roof at the antenna, in the back.)

Sorry to say, but the old days of shafted or standard DIN stereos left us a while ago.

Dtaylor3

Same thing happened to me when I first bought mine a 4 years ago.... Factory amp is bad. You can bypass it or buy a new amp

LEXXIUM

iTrader: (1)

I just almost replaced the whole system myself for about 250 all new and that's including a pioneer 10" subwoofer all 4 speakers(not installed yet and a pioneer blue tooth media unit, pioneer 400w amp, and all the wiring.
All of my speakers were deteriorated, the amp wa wa wa was sounding like that, the only good thing was a head nak factory which I still have laying around, but yes it needed to be replaced, and I wasn't paying big bucks for someone to do it. The only way out was learn the system and replace everything on the cheap myself.
I replaced everything knowing I won't have to deal with it for a while, I learned a lot reading this forum.
If you vave some basic tools you can handle it!!

matguy

Yeah, the only real car-specific annoyance is the factory sub location. The depth is low and the grill attaches to the factory sub. However, even if you have the Pioneer system you can put in the Nakamichi sub, power it off any aftermarket amp and it should drop in and have your grill attach to it. It won't win any contests, but it's a decent sub. It's 5 ohms, so it'll get 4/5 of whatever the amp is rated for at 4 ohms and the amp will stay nice and cool. The factory Nakamichi system should be giving around 120 watts to the sub, so any amp rated around 150 watts is fine. You could probably be fine with a 200 watt amp, but it won't help you much as you'll generally get rattles and the semi-free-air trunk pressure interfers with the rear deck speakers well before you hit the top end of your amp or sub.

If you want to go with anything bigger or boxed you're well in to custom design unless you're just dropping a boxed sub (pre-fab or built) in the tunk. But then all your bass has to travel out the stock sub location since that's the only path to the main cabin; you lose a lot.

scdfndr

Thanks for all the input. Sorry, I had to be away for a few days. So, is there a consensus as to the best recommendation? As for the quality of the factory Nak system, in fairness, it's 23 years old, and my daily driver.

In response to one poster, I have not used to CD changer in years. I assume it still works, but likewise assumed the same problem would occur whether I played the radio or CD player. Should I try the CD?

Dtaylor3

I'm 100% sure it's your factory amp. I bypassed it and took the factory amp out all together. Takes a couple hours. It's in the trunk right under the the gas cap on the passenger side

scdfndr

UPDATE: Thanks to the member who suggested trying the CD player. I hadn't used it in years. I tried it today and it worked fine, all of the speakers sounded normal. I let it play for an entire song and no trouble. So, its only when I play the radio that the problem occurs. (There's a cassette player, but my recollection is it doesn't work at all.) I assume this is good news. So. What now? (Sorry for the need for a stereo 101 lesson. I love my 5-speed SC300, but I know how to drive it, where the gas and oil go. That's about it.) Thanks all.