New Member From Pa, Thanks For Having Me.

[Tony J]

Hi folks

Earlier in 2012 I purchased my first Lexus, a 2000 ES300 Platinum Edition with 54,000. Having never driven a Lexus, it goes without saying that I was floored by the overall quality, performance, silence, and Nakamichi stereo. It is 99% mint, and will become my son's first car because of my most recent purchase.

Apparently the Lexus bug had entered another life and I began searching for somewhat of a classic. During holiday vacation I was cruising Craigslist and stumbled upon a newly listed 1992 SC400 with 58,000 miles at a scammer price. After a day of contemplation, I called the number which was well out of state. To make the long story short, I am a very proud owner of a Diamond White Pearl Gold Edition SC400 with car phone and original gold spoke BBS type wheels.

Much has been accomplished in the past 3 weeks:

Replaced headlight assembly: direct from Japan

Trunk Struts replaced

K & N Air Filter

New back seats

Working on a second amp for the Nakamichi Stereo

Disassembled console, pulled temp control unit, had it repaired, console back together

I will post some pictures soon, and look forward to SC discussions with the fellow members. Thanks again.

[SW03ES]

Welcome!

[Tony J]

Hopefully, someone has had this similar experience and can give some advice. Upon installing the second replacement amp, the fuse blows. I have tried mulitple times to no avail.

The existing amp allowed the radio and CD player to turn on, but no sound.

The first replacement allowed helicopter noises out of the speakers: repetitve loud noise regardless of the volume control setting.

This second replacement amp is shorting the fuses.

I can put the original back in, no blown fuses, but again no sound.

Is it possible that I got another bad AMP off of ebay. They were both on the lower price side: $200

Help please, thanks.

[1990LS400]

Assuming that your phone is an original dealer installed Lexus phone system ... A defective phone ECU can blow fuses and prevent sound. I'm more familiar with the later Lexus phone systems in which the solution is to disconnect the connectors from the phone ECU in the trunk and then to connect the large male and female connectors together to complete a circuit - did this on a friends 99 LS400 a couple of years ago to restore the sound and keep fuses from blowing. He had purchased both a used head unit and amp trying to solve the problem but that didn't help.

You might as well rip out all the phone components anyway. Before 2004, dealer installed phone systems were all analog and they are useless today.

When removing phone system components, do enough disassembly to unplug them. Never cut a phone system cable as that can cause problems.

[Tony J]

Thanks for the response. I did pull the phone, but the 3 button control on the steering wheel remains. Would you happen to know where these mating plugs would be?

[1990LS400]

When you said you pulled the phone, did that including removing or at least disconnecting the phone ECU? According to the attached diagram, the phone ECU is at the left side of the trunk - either under a false floor or behind a trim panel. I don't know if the 92 SC phone system has the two mating connectors at the phone ECU like the later systems do ... let us know if they do.

You should be OK leaving the phone controller on the steering wheel - never heard of it causing a problem and you could have trouble find the plastic blank to fill the hole if you remove it.

[Tony J]

Thanks for the schematic. There are 2 plugs in that area that were unplugged and I proceeded to mate them prior to troubleshooting the amp. The SC set-up looks precisely that the LS.

I am going to purchase an aftermarket Alpine amp from Crutchfield to replace the Nak amp. The Crutchfield rep assured me that, with the appropriate plug adapters, it would provide the power required. I will keep you posted. Thanks again for your assistance.

I was looking at other Lexus models, including new, but I really like the old style and engineering. It is becoming an enjoyable hobby. I even read the "Relentless Pursuit" book by Chester Dawson to learn more about the history of the company. What model do you own?

[1990LS400]

I am going to purchase an aftermarket Alpine amp from Crutchfield to replace the Nak amp. The Crutchfield rep assured me that, with the appropriate plug adapters, it would provide the power required. I will keep you posted. Thanks again for your assistance.

Were the replacement amps supposed to be functional? If you've tried three amps and none of them work, maybe something besides the amp is causing the problem?

I've seen a number of threads over the years about corrosion in the early SC audio wiring system causing no sound. Have you checked the wiring harness at the amplifier for corrosion? I hope the Crutchfield rep knows what he is talking about ... just hearing the name gives me the creeps ... gave up on them long ago due to their cluelessness.

When the sound of my 00 LS Nakamichi system failed some years back, people on forums told me that the amp was the problem so I tested my amp in a friends similar LS400. My amp worked fine in his car. The problem turned out to be in the head unit - a company in Florida fixed it but they no longer repair Nakamichi.

Before you go any further, do you know anybody with a known functioning Nakamichi amp you could try in your car or try your amp in his car?

[Tony J]

I am trying one more amp, if that does not work, then I will install an aftermarket head unit and speakers with new wiring. I wanted to stick with original, but the vehicle, while in great cosmetic and running condition, is 21 years old.

I contemplated the 3 amps, but this is the story: the original amp which I have, does not blow the fuse, allows the stereo and CD to function, but no sound. The 1st replacement amp I tried caused a helicopter noise in the speakers, allowed function of the head unit and CD, but did not blow the fuse. The second replacement simply blows the fuse when I plug it in. The original still works as stated, but no sound. All of the symptoms have been discussed many times on the forums, and most refer to a bad amp. Maybe it is wishful thinking, but there must be a good amp out there some where. I do not know anyone with an SC400 or SC300 that uses this amp.

I see no corrosion around the wires or amp, and I have spent enough time back there.

After further discussion with Crutchfield, they now tell me that a compatible amp is not available, and that I would have to rewire the vehicle with new head unit, speakers, etc.

I am hoping that I can have a local service perform an install for under $500.

Thanks again.

[1990LS400]

After further discussion with Crutchfield, they now tell me that a compatible amp is not available, and that I would have to rewire the vehicle with new head unit, speakers, etc.

Of course that Alpine amp is not compatible. Crutchfield employees have been clueless since I begin dealing with them in the 70's and gave up on them in the 80's. The Crutchfield website is packed with obvious application errors. Why don't you determine which component is causing the problem before flushing more money away?

[Tony J]

I am getting refunds on the amps minus shipping costs. The latest should arrive by Thursday. If it does not work, I will take thecar to a reputable installation service to troubleshoot or simply replace with aftermarket. I am not qualified to begin troubleshooting the wiring or components. By the way, I am happy to hear that I am not the senior member :D

[Tony J]

Hi guys

Music in the SC. Happy to say that the 3rd replacement AMP works perfectly!! It is hard to believe that there that many bad amps out there being sold. In this case "you get what you pay for" applies. Thank for your advice and look forward to sharing info with you in the future.