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Was wondering if you have figured out the root cause and can repair issue in a reasonable amount of time? And what you might charge me to get mine repaired?
Update: Mark Levinson 86280-0W260 Amp. I got my parts and did the repair. Still one thing I'm a little nervous about, but it's been in there running for about a ½ hour; so far, so good. As I stated in my response to rogersmj's inquiry, if your interested, reply here accordingly. If it holds, I plan to do a writeup on what I've found and what I did including the removal, teardown and troubleshooting and repair. Note, however, that working on that board is not for the faint of heart - you certainly do need at least good soldering experience (more correctly, de-soldering experience!).
Was wondering if you have figured out the root cause and can repair issue in a reasonable amount of time? And what you might charge me to get mine repaired?
Sorry Couldabeen; I'm not really in the repair business, and I'm not confident that I have found the root cause. I have found the components that failed, in a couple of different scenarios, but I still haven't figured out why they failed (and may never know for sure). My interest was in sharing whatever I did discover with other DIY-ers who maybe want to tackle the repair themselves. As I mentioned in my update, it's not for the faint of heart .
If you would like to get it repaired, there are other suggestions in various forums. Most seem to feel United Radio (in the United States) is very reliable and a reasonable turnaround. The prices I've seen from other posters vary between about $425 and $750; probably depends on the actual amp you have. I have a 2007 LS460L with the Mark Levinson sound system (PN 86280-0W260) . That seems to be the most expensive .
Good luck.
Sorry again Couldabeen; I hadn't read your initial problem description. I'm not positive about the 430's (although I had one; 2002), but it doesn't sound like the amp to me (if it's a similar arrangement to the later models). In my case (and most others with amp problems), there is no sound from ANY speakers, or there is a chirping or clicking sound from ALL speakers. I think the voice command and telephone speaker are the same (front left) and it seems to work for you. In my case, that speaker is also powered by the same audio amp as the rest (as it is also used for music the rest of the time). You could be having problems with the head and somewhere (e.g. Radio/tuner..).
Sorry again Couldabeen; I hadn't read your initial problem description. I'm not positive about the 430's (although I had one; 2002), but it doesn't sound like the amp to me (if it's a similar arrangement to the later models). In my case (and most others with amp problems), there is no sound from ANY speakers, or there is a chirping or clicking sound from ALL speakers. I think the voice command and telephone speaker are the same (front left) and it seems to work for you. In my case, that speaker is also powered by the same audio amp as the rest (as it is also used for music the rest of the time). You could be having problems with the head and somewhere (e.g. Radio/tuner..).
Has anyone actually tried to repair the ML amp in their 460, or does everyone just send them off to be fixed? I am willing to bet it is either an issue of a soldier joint failing (common with years of heat cycles that an amp as poorly ventilated as ours goes through), or possibly a transistor going bad (likely the "short" lots of people have been told their amp has). Both are easy fixes, even for a novice. Hopefully mine never has an issue, but if it does, I will look into repairing it myself. if someone has found a schematic for the amp (highly doubtful), I would much appreciate a copy of it please.
Has anyone actually tried to repair the ML amp in their 460, or does everyone just send them off to be fixed? I am willing to bet it is either an issue of a soldier joint failing (common with years of heat cycles that an amp as poorly ventilated as ours goes through), or possibly a transistor going bad (likely the "short" lots of people have been told their amp has). Both are easy fixes, even for a novice. Hopefully mine never has an issue, but if it does, I will look into repairing it myself. if someone has found a schematic for the amp (highly doubtful), I would much appreciate a copy of it please.
Read this thread, then, rephrase that question. You sound like me!!!
Update: Mark Levinson 86280-0W260 Amp. I got my parts and did the repair. Still one thing I'm a little nervous about, but it's been in there running for about a ½ hour; so far, so good. As I stated in my response to rogersmj's inquiry, if your interested, reply here accordingly. If it holds, I plan to do a writeup on what I've found and what I did including the removal, teardown and troubleshooting and repair. Note, however, that working on that board is not for the faint of heart - you certainly do need at least good soldering experience (more correctly, de-soldering experience!).
Hi, I have an amp with the same issue as yours did. Can you do a brief write up of the components you replaced? It would be much appreciated.
I'll include a couple of pic's here with a bit of an explanation. More detail will have to wait 'til I have a bit more time In a nutshell, there was a power supply problem.
The unit is pretty straight forward to remove once you get the right side of the trunk liner out. Disassembly of the amp is also reasonable, although you do have to remove 7 screws under the "Mark Levinson" label on the top (Fig 1). There are 5 o-rings on the sides of the board that friction fit into extrusions on the inside. If took me a bit to get them going; push in from the power supply end (and out the fan end - to make it easier to disconnect the fan plugs). Fig 2 just shows how I had to pry on the end of the board to get it to start sliding out or the case.
Fig 1
Fig 2
Fig 3 and 4 show the top of the power supply end of the board with the top shield off and then the shield/heat sink removed from around the transformer. There are 2 screws that were removed from the top of the case, and 2 more that mount it to the board from the bottom.
Fig 3
Fig 4
There are also a 3.3V and 5V supply in the power supply end (which were working fine), but the main one is a DC/DC from 12V to +/- 4V for the audio section. When I first set this up on a bench, I managed to catch a 'scope trace of the -4V supply trying to start up and then aborting. I traced this to Q116 which is shown already removed in the pics above. There are 4 - IRF1404Z FETs (2 pairs of 2) driving the input side of that middle transformer from the 12V supply (filtered by 18 1000uF cap's). You can get an automotive spec'd version of those (AUIRF1404Z) which I ordered. I replaced Q116 and the 4V almost came up and then died again, so back to the drawing board to look at the output side. There are 4 dual Shottky diodes on the output end of that transformer (PN: 43CTQ100). Although I haven't figured out exactly how these are configured, they appear to be used in parallel as I later found one side of a couple of them shorted and was able to get the output going by leaving off the shorted side. Bottom line, I think it was a diode going first that took out the driver FET (did that 2 more times before I was done!). I ended up replacing all 4 diode parts and just the one FET before I got it working so it would handle a load. Fig 5 shows the bottom of the PS side of the board were you can see the bottom of the FETs and diodes (with Q116 removed).
Fig 5
Notes (in no particular order):
1) you of course need to re-mount the FETs and diodes with a thermally conductive paste (like ChipQuik)
2) all these components are also insulated from the heat sink / transformer shield, so don't damage the electrically insulating membranes so you can re-use them
3) you can monitor the +/- 4V outputs by tapping the collectors of any complementary pairs of the bipolar output transistors in the audio section (NPN: 2N6488-> +rail; PNP: 2N6491-> -rail). Fig 6 is a 'scope trace of the supplies coming up and then shutting down when I provided an IGN/ACC input; the 12V input to the supply is always hot unless the 30A fuse in the panel under the passenger side (Fig 7) is blown - I did that too during one test .
4) I have other scope traces; one that shows the 12V input crashing as the supply tries to start and another that shows the output at the same time.
5) I used a little silicon grease on the rings so the board would slide back in easier.
6) I've seen some cite a symptom of blowing out that 30 fuse. I think it's a diode(s) that goes first. If the FETs can survive it will sit there "ticking" as it tries to start up. If it's bad enough that it takes out a FET, as it did for me during one in-car test, then it will blow the fuse and just go dead (and keep blowing that fuse).
7) after all this, the drive signal on the one FET (Q116) is still a bit "jittery" while the other 3 are solid(?). I'm a bit nervous that something else is amiss, but it's been in there about a month now and still seems to be holding up fine. I have to pull it again and stick the remaining trim on and try to re-seal the board (I had to scrape off the conformal coating to work on the board. I'm too cheap to spend the $50 to buy that stuff, so I'm going to use some brush-on electricians tape. I've done some simple tests with it and I think it will do the job Fig_6
Sokay, I am pulling mine and sending it to New Jersey. Spoke with them last week. Just have to get it out of my trunk and box it. Thanks a bunch though! Stay safe.
I have narrowed my audio issue to the wires that come from the frame of the car to the connector. When I hold the wires the apart a little about 5-7cm from the connector the audio works fine. As soon as I bolt the amp into the body of the car and the wires are tight again the audio drops. Has anyone had this issue / know a remedy?
Thanks, Thomas
I have a 2004 with the ML and Nav system. The sound has started cutting out, all channels. I moved the fader control to the front speakers and the sound is fine, left and right. If I add the read speakers, the sound starts cutting out. If you turn the volume control down is works for all channels.
If the volume is turned up past 1/4, the sound cuts out. I presume this is a power amp issue but since it works on the front channels, I am not sure. The power supply for the power amp is working I guess since there is full front L/R sound. I also guess the subwoofer is driven off of the read channels. I am also getting DVD ERROR when I insert the magazine. Not sure if these are related as the system has a communication bus that talks to all of the components.
Any guesses??
I have the exact same problem in my new to me 2005 LX 470. Did you get an answer/solution to this? Is it the amp or the rear speakers?
04-04-20 | 09:06 PM
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