SC- 1st Gen (1992-2000)

SC300 stereo issue

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Old 02-07-16, 09:47 AM
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t2d2
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That seemingly rules out the CD changer and amp, so the head unit is likely the problem. More specifically, the tuner, not the preamp, as the latter would affect the CD changer, too.
Old 02-07-16, 09:56 AM
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scdfndr
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Okay, So, this is something the car stereo shop can repair? Replace the tuner? The Florida shop I described the problem to said they'd seen this and it was likely "the stereo, not the amp or speakers." Can I assume that person by "stereo" meant same as "head unit," meaning the thing in the dash? Thanks all.
Old 02-07-16, 10:04 AM
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People usually use "head unit" and "stereo" interchangeably.

I doubt your run-of-the-mill stereo shop can fix the tuner. You'd probably need to find an electronics specialist for that, and I would seriously question the $$$ value of going that route. Replacing the head unit seems like a much better option.
Old 02-07-16, 11:21 AM
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Can I replace it with a matching unit like the original? I really want to keep my SC all original. Thanks


http://www.ebay.com/itm/1992-2000-LE...VV5ORt&vxp=mtr

Last edited by scdfndr; 02-07-16 at 01:03 PM.
Old 02-07-16, 01:26 PM
  #20  
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Actually. strangely enough, it's likely either the head unit or the CD changer. Because some of these systems strangely pass the tuner signal through the CD changer (or at least the other sources cease to work when the CD changer is removed) it could be the CD changer causing this. Either some of the circuitry in the tuner section in the head unit has gotten dodgy, or the transfer circuitry in the CD changer is failing.

If you unplug the wiring harness from the CD changer does the FM audio completely cut out? (not muffled, but completely cut out.)

If it does that confirms that the signal passes through your CD changer. It doesn't confirm which has failed, but confirms that it could be the CD changer. If it doesn't cut out then the problem is certainly within your head unit and it would need to be replaced. Either with a same model head unit (ebay or junk yard) or start new with a aftermarket system.

Back to if it does cut out, I think the only real way to find out is to replace them. I think the CD changer is a bit easier to replace. Considering that you don't use it, it may not matter that much if you get a fully functional one to replace it with, as long as it passes the signal. I think it's almost 50/50 on where the problem lies.

If you do go for an aftermarket replacement you can still use your factory Nakamichi amp to power your door and rear deck speakers, but you'd need a new amp for your sub and the wiring needed for that.

A standard stereo shop can replace parts, but it's pretty rare that they can fix a failing component, especially factory component. They would be able to take care of you if you wanted to go the aftermarket route. Tell them to use the standard wiring harness kit and that'll provide signal to the amp for the front and rear speakers, but run a new power and signal cable for the new sub amp. You can remove the factory CD changer and it becomes a decent place to mount the new amp. Your Nakamichi sub is 5 ohms and can handle 120Watts with no problem.
Old 02-07-16, 04:27 PM
  #21  
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Should I be able to figure out how to unplug the wire harness from the CD changer? I'm sure that's obvious to most, but I'm not at all mechanically inclined.
Old 02-08-16, 10:39 AM
  #22  
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Originally Posted by scdfndr
Should I be able to figure out how to unplug the wire harness from the CD changer? I'm sure that's obvious to most, but I'm not at all mechanically inclined.
After writing up what I wrote below, I found this: http://www.carstereoremoval.com/htm/...40092_00CD.htm


For the most part, yes. You'll have to pull the carpet lining on the side of the trunk, but start with the bottom lining that covers your spare tire. The side carpets are bound to a somewhat rigid, though still workable material that forms the shape of the trunk. You might need to start with the back piece and work to the side with the CD Changer. Save the plastic clips. From there, if I remember correctly, you might need to take off a few bolts, I don't remember the size, but probably 12 or 13mm. The wire harnesses are there for both the CD Changer and the Amplifier, which is right under the CD Changer. As you can tell, the CD Changer is the black box, the silver aluminum box is the amplifier. Pull the plugs from the black CD Changer, leave the ones plugged in to the silver amplifier. See what happens.

When you're done fussing with the CD Changer push the carpet panels back in and use the clips to re-secure it. Make sure to feed the manual gas cap release through the hole it was originally fed through. The panel in the back is secured by metal clips at the top.
Old 02-08-16, 11:08 AM
  #23  
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Thanks for this.

For what it's worth, today I payed the CD player for the car stereo guy. I then switched to the radio which now barely plays at all. He said it's the tuner and IF the tuner is in the head unit, I should simply buy a used one on EBay (there are a couple) and they can install it if I can't.

Guy in the Florida repair shop, who seems to know what he's talking about agreed it's definitely the tuner, which is located in the head unit and doesn't run a signal through the CD changer, at least according to him.

Thanks for all of the advice. It probably saved me a good chunk of money. I'll report back the results.
Old 02-08-16, 12:52 PM
  #24  
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Oh, the tuner certainly is in the head unit in these.

In all honesty, I'm surprised the car audio shop guy is willing to install an Ebay sourced stock head unit. It's not terribly hard or anything, I'm just surprised they're willing to do work with components they didn't sell. If you want to do it yourself, just make sure to keep good track of all the screws and bolts and where they go.

On the CD Changer being in the signal path theory, people have mentioned it, so it might be worth checking. In all seriousness, I thought it sounded odd when I ready about it, but with the way the phone controls go straight to the amp rather than the head unit, not a whole lot surprises me with these. I'd try with my Nakamichi system, but the head unit had already been converted to aftermarket before I got it, so the stock CD Changer isn't part of the system. I ended up finally removing it when I put an aftermarket sub amp in about 6 months ago.
Old 04-05-22, 11:53 PM
  #25  
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Originally Posted by 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.
I have the same issue right now. Anyone find a solution by any odd chance? I tried connecting my CD changer but all I hear is the sub. I know the speakers work because when I change stations on FM, I can still hear the beep coming from the speakers, however, when I listen to tape or the radio all I hear is the sub and no sound coming from speaker.

Last edited by nismooo; 04-06-22 at 12:05 AM.
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