1993 Lexus LS400 Nakamichi System Fix

[astrochex]

So the car we got for my son (he did pay half) had a busticated audio system. He said it wasn't a big deal at first but when given the choice between window tint or car audio fix as a Christmas present, he chose the fix.The car has the upgraded Nakamichi system which has an amplifier (4 x 40 plus 1 x 100 @4ohm) and a CD changer. There appear to be tweeters in the sail panels, midrange in the doors, coax in the rear doors and a subwoofer. The problem was that when the system was turned on, there was popping and hissing that was not affected by volume or source. I checked fuses and connections and they were all OK. I had to resort to sending the HU and amp off to a far away repair place. I chose this place because he published a lot of tutorials on the particular system that were a great help in removing the components. He confirmed the HU was fine but the amp power section was defective. He did not want to repair the amp because he did not have a schematic of that circuit. I only paid for shipping on that one.

I located another repair shop that was much closer, within driving distance. This guy, John at Factory Radio Service & Repair (www.factoryradioservice.com), was great. I took the HU and amp in on a Saturday. He had it diagnosed, fixed and added an aux input (at my request) by the following Tuesday. I picked it up the following Friday and put her back together. Viola, I was greeted with loud, tunes with no noise. AM, the CD changer and the aux input all work perfectly. I did some tweaking of the available controls, bumping the midrange and bass while limiting the treble. The cassette input has not been checked. I still need to figure out the FM issues and the retractable antenna for a complete fix, but those can wait.

Here are pics of the stuff.

The nicely integrated HU and whats behind it. Kudos to Lexus for making the removal such an easy process.



Cover for the CD changer and amp that was a bitch to remove. The trim panels were stiff and interlocking, something that wasn't obvious at first. Replacement was little easier, thanks to being able to climb into the large trunk.


The changer and amp rack. Its a nice piece, it even has padding between attach points and the body.

The source of all the fuss. Its very compact. You can see from the guts what went wrong. It looks like mini marshmallows had melted. I did not open up the repair unit since he applied a warranty sticker I did not want to break.


All buttoned up.

[Notloudenuf]

So the caps gave up and melted out their internals?

[astrochex]

Perhaps, I did not note the specific components that failed.

[cajunner]

normally, a lot of goop that has the look of thick glue sitting under capacitors, is actually just glue. The way capacitor electrolyte looks after the cap has failed is not the same. I do not see any visible faulty items in the pic, but it hardly matters on what appearances show, since the amp was determined to be faulty. A system such as what comes in those cars, seems easily upgraded with the addition of higher quality aftermarket tweeters and a higher output subwoofer, possibly placed on a baffle to allow a larger cone diameter to fit.

[astrochex]

Because the amp was faulty and the first guy could not fix it, I took a flyer on a $70 unit on eBay. It had a similar appearance with the glue (I thought it was intestines) so I did not bother to hook it up since the HU was at the repair shop. And of course, I did not think to hook it up when I was installing the repaired amp.

I was thinking about how to make it sound better and upgraded speakers were my first idea.. But that will wait until I get my system going and perhaps the wife's.