Last week I sent my Mark Levinson head unit and amplifier to United Radio in Syracuse New York. Due to a no sound issue. Both units tested properly found no malfunctions. I reinstalled both units and the no sound issue is still present. It was suggested by them that I clean the junction box underneath the center console where a lot of the wiring harness connect. I thoroughly cleaned them with CRC contact cleaner and the wiring harness that attach to the back of the head unit and the amplifier as well.

I still have no sound.The technician at United Radio advised me that they are the only certified/authorized repair for these components, not the dealership. Now that both units have been checked out and found no problems my only recourse is the dealership. Maybe a defective wiring harness etc. Any recommendations or advice would be greatly appreciated.

 

Did you check all the fuses? Wires don't go bad unless they are physically cut or disconnected. A fuse would blow out first before a wire gets fried.

 

Both units power up. Head unit interfaces with display screen. Amplifier power red light indicator is on.

 

Wires and insulation intact no loose connections that I can see. Never a drop of water in trunk area we’re amplifier mounts. Amplifier was tested for moisture damage, none detected. Hot and cold stress test also conducted no faults found. Amplifier was given the same stress test as before it left the factory per M.L. Tech.

 

Spoke to Tech at Mark Levinson / United Radio they are helping me troubleshoot. He suggested checking 2-30 amp fuses behind the right side of the dash. I have to track down where they are and see if they are working.

 

Under the glove box stick your head under there with a flashlight and you'll see a white plastic cover with all the fuses labeled on it. I bet good chance it's a fuse.

 

I experienced the same issue on my 2013 GS450H, everything is working but no sound. I tried to reboot amplifier before going into deep troubleshooting by disconnecting just a power plug (white+black cables) for like 4 minutes and it fixed the issue somehow, just wanted to share here with you guys.

P.S. i started having issue from a long 8hr drive by switching from iPod option when needed to charge a phone via USB outlet and bluetooth several times `

 

Did you resolve this issue? Just trying to see if you have any updates.

 

I also have a Mark Levinson audio system in a 2015 RC F. I don’t get any sound out of the speakers, even though I can see my iPhone playing the track on the navigation screen. I’m looking for any similar experiences and following this thread for information related to my concern.

 

I have a 2012 GS450H (its the newer shape) with the Mark Levinson sound, a few weeks ago there was no sound. Turned the car off and on and the sound came back. Problem got worse as the weeks went on until it would take 4 or more on/off cycles to get the sound working. It was fine once it was running though.
Had code B15C3 as a memory code (hold menu button and cycle headlights 3 times) and it would appear as a current code when the audio didn't work.
I work as an electronics repair tech so I pulled the amp apart - had no signs of water damage on mine as many others seem to get but there is a row of 12 small electrolytic surface mount capacitors on the back of the D class amp chips. These are a 22uf 16V caps. They should have an ESR of about 3.5milli ohms which 10 of mine were close to that but one was at 6 milli ohms and another at 11. I temporarily replaced those two with something I had that was similar and so far the issue is gone. I have ordered the correct ones and will change them all later.
Otherwise they seem to be a very well built amp, even with conformal coated PCBs and Rubicon capacitors in the power section etc.
I think for most of them it would be a relatively low cost, straight forward repair
There are places who offer repairs but its not cheap, especially if you are handy with a soldering iron

 

Hi and Welcome! Great 1st post.

Can the Caps be replace for better SQ sound with something like Nichicon or Mundorh or other to upgrade and improve?

 

I can't find a part/datasheet which exactly matches the amplifier IC's used (it may be a proprietary IC that they have used) but I've looked through some similar ones. Since they are a D class amp which is basically a switched mode power supply there are high frequency currents/voltages which electrolytic caps are usually not the best choice for.
My best guess currently is that those 22uf caps are used to buffer a 1/2 supply voltage point for the D class amp chips which are doing multilevel pulse width modulation as a way to make cleaner outputs. I doubt they are directly in the audio path, but a more stable supply could improve the sound quality somewhat.
The datasheets for other similar ICs go into a bit of detail around the capacitors required as they work pretty hard in that part of the circuit - a lot of high frequency current. They usually recommend 2X ceramic capacitors in parallel with a reasonably high voltage rating and an X7R or similar dielectric type which is pretty standard for an application like that (X7R caps stay pretty constant with applied voltage and temperature variation where some other dielectric types don't). Using one physically small/ relatively high ESR electrolytic cap in that location (as in the original design) will see the caps run pretty warm and fail fast.

I'm going to try a stack of 2X 10uf ceramics soldered on top of each other to replace each 22uf electro cap. In theory they should have a much lower ESR/Hence much less heat, should perform better and pretty much last indefinitely

something like these from Mouser: 810-C3216X7R1HK160AC

will report back if it works..

 

I remember there were instances where you had to be careful with using only ceramics as supply caps. Something with the low ESR and a potential for ringing.

Separately, I did come across this post in another forum for a failure, with main difference being that the amp fuse would blow when amp was connected. The amp layout looks similar enough to the GS':
https://www.lexusownersclub.co.uk/fo...cation-nx300h/

The main part: