Nakamichi Amp - Do They Fail? (1 Viewer)

[PabloCruise]

I have a '99 LX 470 that came w/ the Nakamichi 6 disc changer head unit.

I replaced the head unit w/ a Pioneer, and kept the factory amp: Nakamichi Update - '99 LX 470 - https://forum.ih8mud.com/threads/nakamichi-update-99-lx-470.1066006/

The other day the audio was pretty quiet. Today the only audio now is some random humming noise.

I reset the head unit, no change.

Does anyone know if these amps fail? Does anyone know a diagnostic procedure?

 

[PabloCruise]

Coincidentally, our boy just turned 16 and has been driving the LX.

My guess is that he has been stress-testing the audio...

 

[Kamran Khan]

I had a Nakamichi amp from a different Lexus, I posted it for sale on eBay and was listed for a year. I tossed it in garbage and removed eBay listing. Get rid of it, not worth spending money on. Get a new amp and new head unit.

 

[PabloCruise]

You may be right, but I would not mind finding one that will drop right in!

 

[dbfw]

I wonder if they have any internal fuses protecting the output transistors or if there's a protection circuit controlling a speaker relay or something simple like that? I haven't had to open my Nakamichi amp yet, but I do have a late '60s receiver inside the house that I use for my turntable, and have had to go through it the last couple years replacing electrolytic capacitors that have finally given up after 50+ years. I wonder how serviceable the Nakamichi amps are? Granted as mentioned earlier there's probably an easy supply of them free for the price of shipping people might be giving up, but it would be interesting to know the failure mode if nothing else.

 

[PabloCruise]

I pulled the amp - it is a Nakamichi piece:

I saw this on the outside, bottom. Not sure if this is from the inside of the amp, or somehow liquid got way underneath the passenger seat. With my wife and boy driving the truck - anything is possible!

I started opening the case, but there are a lot of Philips screws holding that board down, so I stopped. No sign of internal fuses thus far:

 

[dbfw]

Oh boy, yeah that's a pain, reminds me of when I had to re-cap my oven control board, it was a bear to get apart. I think I see a ribbon cable in the upper left of your picture, so maybe once that board is loose it can either be hinged up, or even better unplugged from the rest of the unit?

Not that any of this is a productive use of your time, more morbid curiosity on my end!

 

[PabloCruise]

Not sure if anyone cares, but I did talk to Nakamichi USA about service for these amplifiers.

It sounds like the car audio company shut down and was acquired at some point.

They recommend United Radio in NY for repairs: Customer Support - United Radio - https://www.unitedradio.com/customer-support/

I also found these guys in CA, Short Circuit: nakamichi – Short Circuit Car Audio Repair – Contact Us Today! - https://www.shortcircuitrepair.com/nakamichi.html

 

[dbfw]

That's good to know, I plan to keep my Nakamichi amp and it's good to have service options when my time comes due. I recently had a good experience with Circuit Board Medics - Automotive & Appliance Circuit Repair - https://circuitboardmedics.com/ repairing my oven control board. They don't list many Toyota standard repairs, but I think they try to do custom and will at least eval your part.

 

[PabloCruise]

I am also wondering if a failing amp can cause a current drain.
If I looked at the wiring diagram, I am sure I could answer that question.
We may have had a current drain in place with this amp that failed completely.
I was able to lay my hands on another, and it has issues - certain frequencies or levels will cut out.
And then last night the 470 was down around 11 volts - uh-oh!

 

[PabloCruise]

Some updates...
I sent the amp to New York to United Radio, they called me back and said they couldn't help, so they sent it back.
Then I sent it to CA to Short Circuit. I had to confirm they got it. When they finally called back, they said it tested good, but they could re-solder some joints for me. I had them re-solder the joints and then when I got it back and lugged it I just get a series of popping noises from the audio.

At this point I was wondering if it was my head unit?

My friend and I opened up the amp I got from a 470 being parted out and there was a loose screw rattling around in there! My EE friend went over everything and said he would like to replace the caps, but they are fixed to some pretty broad traces.

Anyway, I threw the 2nd amp in and the stereo works! Long story short, I would not advise giving Short Circuit any $.

 

[PabloCruise]

Does anyone have the pin-outs for the Nakamichi amp?

 

[dbfw]

Thanks for the update! Good to know what our options are (or aren't) when it comes time to service these. I'll take a look at my 99 FSM to see if they're in there, but I doubt it since I don't have the supplemental wiring diagram one, just the volume 1 and 2 maintenance and repair.

 

[Africaster]

I have my Nak amp somewhere in the garage if anyone needs one

 

[PabloCruise]

I have my Nak amp somewhere in the garage if anyone needs one

Yes please, sending PM now.

 

[PabloCruise]

Thanks for the update! Good to know what our options are (or aren't) when it comes time to service these. I'll take a look at my 99 FSM to see if they're in there, but I doubt it since I don't have the supplemental wiring diagram one, just the volume 1 and 2 maintenance and repair.

Thank you! Please LMK what you find.

 

[PabloCruise]

Well the stereo has been problematic for a while now.
Last weekend when I was driving the truck I heard the subwoofer making an awful noise, so I pulled the panel to check on it.
I noticed the subwoofer cone did not move in and out like you would expect most speakers to.
Resistance measured 1 ohm, vs. the 4 spec'd on the speaker.
I disconnected the sub, hoping that was my issue.

It wasn't. The stereo still makes fuq'd up noises after a while.

 

[PabloCruise]

It looks like this is a possible replacement for the factory Nakamichi 4 ohm sub, eh?

Kicker 48CWRT674

CompRT Series shallow-mount 6-3/4" subwoofer with dual 4-ohm voice coils

www.crutchfield.com

Comp RT 6.75" 4 Ohm Subwoofer | KICKER®

KICKER produces high-performance car audio, vehicle specific solutions, marine audio, home and personal audio, and power sports products since 1973.

www.kicker.com

https://www.kicker.com/files/dimensions/48CWRT67-CSD.pdf

Kicker 48CWRT674

CompRT Series shallow-mount 6-3/4" subwoofer with dual 4-ohm voice coils

www.crutchfield.com

 

[PabloCruise]

I started a new thread for subwoofer replacement:

Nakamichi Subwoofer Replacement

I know there are lots of threads on our subwoofers already, but nothing looked quite like I want to do. We have a '99 LX470 that came w/ the Nakamichi stereo system. I replaced the head unit, and then about 4 years later I was having some amplifier issues. While I was figuring out the amp, I...

forum.ih8mud.com

 

[shtbrwn86]

What are the options for replacing the amp with aftermarket? Does an Infinity/Alpine etc just drop in connector wise... I know I will have to secure it somehow. Just wanted to know if it can be made plug-n-play.