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'94 Ls400 Nakamichi Stereo- Poor Audio Quality For Cd Changer

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Not only is my cd audio quality terrible, but at a certain volume the audio clips and cuts out. is it my head unit or the contacts from the cd to the amp. Anyone else having this problem?

1994 LS400

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Not only is my cd audio quality terrible, but at a certain volume the audio clips and cuts out. is it my head unit or the contacts from the cd to the amp. Anyone else having this problem?

1994 LS400

Sounds like the amp is bad.

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Not only is my cd audio quality terrible, but at a certain volume the audio clips and cuts out. is it my head unit or the contacts from the cd to the amp. Anyone else having this problem?

1994 LS400

Sounds like the amp is bad.

The radio is crystal clear though.

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Not only is my cd audio quality terrible, but at a certain volume the audio clips and cuts out. is it my head unit or the contacts from the cd to the amp. Anyone else having this problem?

1994 LS400

Sounds like the amp is bad.

The radio is crystal clear though.

Run a cd cleaner a few times (the one with the brushes on the disc) clean the brushes between cleanings. ;) Then check the connections. Make sure the cd's are clean also.

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After a few too many minutes working on solving this issue, it seems that the factory installed car phone was the issue. to remove the phone ( and its negative affects like auto volume attenuation) just unplug the smallest wire plug from the back of the head unit. Then remove the fuse from under the steering fuse box to reset the stereo system.

It figures, always look for simple solutions first. I actually found schematics for the amplifier and took it apart, assuming there was a beat capacitor or resistor somewhere.

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After a few too many minutes working on solving this issue, it seems that the factory installed car phone was the issue. to remove the phone ( and its negative affects like auto volume attenuation) just unplug the smallest wire plug from the back of the head unit. Then remove the fuse from under the steering fuse box to reset the stereo system.

It figures, always look for simple solutions first. I actually found schematics for the amplifier and took it apart, assuming there was a beat capacitor or resistor somewhere.

That's odd. Audio system mute issues from the dealer installed car phones have usually affected the sound from the radio, cassette player and CD player equally -- at least that is what has been reported in previous threads. Usually disconnecting all the phone system components will resolve the problem -- on some Lexus phone systems, two connectors have to be plugged together after disconnecting them from the phone ECU in the trunk. Yours is the first time I've heard of anyone having to unplug a connector from the head unit to resolve this type of problem.

To illustrate my point, several of us on this forum have attached the mute wire on aftermarket phone kits to a mute pin on the factory prewire phone harness -- when a call is in progress on on our aftermarket phone systems, the audio system is muted regardless of whether the radio, cassette or CD is in use.

In case you don't already have it, attached is the full audio system diagram for a 1994 LS400 Nakamichi system.

1994_LS400_Nakamichi_diagram.pdf

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After a few too many minutes working on solving this issue, it seems that the factory installed car phone was the issue. to remove the phone ( and its negative affects like auto volume attenuation) just unplug the smallest wire plug from the back of the head unit. Then remove the fuse from under the steering fuse box to reset the stereo system.

It figures, always look for simple solutions first. I actually found schematics for the amplifier and took it apart, assuming there was a beat capacitor or resistor somewhere.

That's odd. Audio system mute issues from the dealer installed car phones have usually affected the sound from the radio, cassette player and CD player equally -- at least that is what has been reported in previous threads. Usually disconnecting all the phone system components will resolve the problem -- on some Lexus phone systems, two connectors have to be plugged together after disconnecting them from the phone ECU in the trunk. Yours is the first time I've heard of anyone having to unplug a connector from the head unit to resolve this type of problem.

To illustrate my point, several of us on this forum have attached the mute wire on aftermarket phone kits to a mute pin on the factory prewire phone harness -- when a call is in progress on on our aftermarket phone systems, the audio system is muted regardless of whether the radio, cassette or CD is in use.

In case you don't already have it, attached is the full audio system diagram for a 1994 LS400 Nakamichi system.

Does anyone know the location in the vehicle of the car phone tranciever?

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Does anyone know the location in the vehicle of the car phone tranciever?

Here is a diagram showing the location of components: http://www.toyodiy.com/parts/p_U_1994_LEXU...EPGKA_8615.html

Although the diagram sort of makes it look like the telephone ECU is in the car interior, it is really on the left side of the trunk behind the trim.

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Does anyone know the location in the vehicle of the car phone tranciever?

Here is a diagram showing the location of components: http://www.toyodiy.com/parts/p_U_1994_LEXU...EPGKA_8615.html

Although the diagram sort of makes it look like the telephone ECU is in the car interior, it is really on the left side of the trunk behind the trim.

Im sorry but the link provided does not work, is there anywhere else to find this diagram?

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Im sorry but the link provided does not work, is there anywhere else to find this diagram?

Odd, the link works for me. I'll download and attach the diagram.

post-2157-1245460478_thumb.png

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Does anyone have a video or instructions for the removal of the amp for a 94 LS400? Lexus has told me that it sits above the CD changer in my trunk. Any pointers on installing a replacement (used) amp? The P/N Lexus gave me was 86260-50110 but loo king at eBay, sometime PN 86280-50141 is given. Does anyone know which is correct or if either will work?

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1990LS400,

Thank you. You have the correct diagram for my CD Changer. I was able to tap into the audio output and connect RCA cables. I now have a AUX line in and attached a Bluetooth adapter.

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