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Robin_M · 08-04-2007, 05:44 PM

Some owners are aware of the RF noise interference that effects the home theater audio amplifier of certain late model coaches. Monaco does have a fix for it now, however in my opinion, the "fix" is overkill.

They have published SB 07-07-08, which they say is for the 2007 Camelot/Scepter and below that exhibit the problem. Monaco will authorize the installation of a 3-piece kit that consists of a 6-channel Home Theater switch box, a 110V-to-12V 15 amp converter, and a harness (which includes a relay) to wire both of these into the system. To the best of my knowledge, the new speaker switch box also contains additional audio filters, although the documentation does not say that.

The concept is that while the coach ignition is off, the power to the home theater amp is supplied to by the isolated new converter, which plugs into the inverter outlet in audio compartment above the driver. That eliminates any interference inflicted via any 12v power source within the coach.

There is a relay in the power harness that performs two functions when the ignition is on. First it disconnects the power from the converter, which turns off the home theater system. Secondly it switches the audio directly to the speakers (except for the center speaker). So as you are underway, the radio acts like a conventional dash radio, bypassing the home theater amp. That, of course also eliminates the RF noise in the amp from the alternator or any other source.

Everything works as I've just described, however, the converter inflicts a new and greater problem.

With the kit operating, all of the speakers would cut in and out once a certain volume was exceeded (about mid-way up the volume adjustment). For some reason, this new interference was present in the speakers whether or not the new converter was supplying power to the amplifier (presumably transferred via the relay).

The good news, however, is that I was able to resolve the new speaker problem. I simply took the new converter, and the relay, out of the system, and reconnected the amplifier power supply back to it's original harness. I left the new switch box in place however, cutting its connection to the relay. Without the relay and the converter in the loop, the radio again always plays through the home theater amp, just as it did before. However, with the use of the new switch box only (which no longer switches anything, but only filters the output to the speakers) there is no longer any interference noticeable from any source, under any condition. Whatever filters are inside the speaker switch box are, in fact, doing the job.

So, the problem was resolved, although not quite the way Monaco intended. Without the bulky new converter taking up room in the audio compartment, there is again room to add a satellite receiver, should I ever want to. I am delighted with the final results.

MonacoMama · 08-04-2007, 06:49 PM

I am not sure we had a problem with this, Rob ....Sacs.. is this a problem? Do you need to ask Don about this one while you are still at Camp Monaco?

loranimal · 08-05-2007, 06:47 PM

Have (had) this problem in mine. I ended up just bypassing the video selector box and ran the output from the radio right to the amp. I tried using a dedicated power supply and even a seperate battery to power the amp and/or selector box with mixed results. I lose the ability to use the dash radio to play DVDs to the bedroom TV. So I just installed a DVD player in the bedroom.

I first thought I had an easy fix, as I removed the cover on the pillar and saw a screw going through an audio cable. But that was for the sat dish setup. Replaced that cable.

Now if I could just get the dash radio to work worth a darn. Keeps freezing/locking up during DVD play.

Carl

Robin_M · 08-06-2007, 03:07 AM

Quote:

Originally posted by loranimal:
Have (had) this problem in mine. I ended up just bypassing the video selector box and ran the output from the radio right to the amp.

Hi Carl,

That is interesting. When you did that, did you also disconnected the speaker harness between the radio and the amp? If that fixed the problem, that meant the noise may be entering through those speaker wires and not the amp power supply.

Quote:

Now if I could just get the dash radio to work worth a darn. Keeps freezing/locking up during DVD play.

Have you tried using a CD/DVD lens cleaner disk? I have not had any problem with mine. I see a lot of people complaining about the Magnadyne dash radio, but mine seems to work just fine.

loranimal · 08-06-2007, 05:57 PM

Robin,

On mine, the output of the radio (A/V OUT) ran to the video switch box (DVD IN) via an RCA cable. From the video switch box (DVD OUT) to the input of the AMP (RCA Cable). I tried running the AMP off of seperate power, but the buzz remained. I tried running the video switch off of seperate power and the buzz remained. I tried both at the same time off seperate power and the buzz remained. I removed one of the inline filters and that helped some. I then ran the RCA Cable directly from the radio to the AMP and that got rid of the buzz.

When I had the radio out, I noticed the bedroom speakers were wired into the front speaker harness. I disconnected them since I don't use the radio in the bedroom. Not only that but you couldn't fade out the front speakers without losing the audio out (RCA Cable)

The way mine was/is wired, you have to have the AMP on to listen to the radio.

Carl

Robin_M · 08-07-2007, 03:04 AM

Carl,

My system was wired exactly the same as you describe. However, I never tried routing the line-out audio cables from the radio directly to the amp. Since that worked for you, obviously the hum was being induced through the large A/V switch box that comes with the coach. That's not hard to imagine, as wires run everywhere from that box.

Monaco just explained to me that there is nothing in the supplimental switch box they sent except an audio switch. Originally the speaker output from the radio was not connected to anything (except the bedroom speakers, as you said). With the new switch box, the radio speaker output is directed to the front speakers when the ignition is on. With the ignition off, the switch default is to open the speaker feed from the radio and use the feed from the amp to the front speakers instead, which is what the original harness does. I disabled the switch relay and took out the seperate power supply for the amp that Monaco sent, because it was causing the other problem I mentioned earlier. Now my speakers leads are routed exactly like they originally were, but through the switch box. Curiously, that was enough to stop all the hum (even with the line-out audio cables from the radio still running through the big A/V switch box to the amp). I have no idea why the new supplimental switch box fixed the hum, at this point.

In my bedroom I have a seperate radio and DVD installed. That was an upgrade that came with the coach. So, like you, I don't use either the front radio or DVD in the bedroom. I think I'm going to try your "fix". If it works in my coach, then I can take out everything Monaco just sent me. I appreciate your input.

CoolJourney · 09-03-2007, 09:23 AM

Quote:

Originally posted by Robin_M in another topic:
Bill, did you ever resolve your buzzing problem in the home theatre amp? If so, I'd love to know how, and I've got more info on that if you need it.

No I didn't get the buzzing problem fixed. When we picked up our coach in Wakarusa in early May we were the first to have the "fix" for this problem installed by the factory reps. The fix included a converter as you mentioned above and a black box fastened to the back wall of the cabinet. I don't know what the function of the black box is (maybe it's the switch box you mentioned?) so I have not attempted to play with the setup on my own. Since this installation happened when our windshield wiper problem was being repaired I didn't get an opportunity to quiz the factory reps on what they were doing. As you say, the fix appears to be overkill (and it takes up a lot of real estate in the cabinet). I just unplugged the converter from the AC source, which stopped the buzzing (and some of the home theater functions). We are headed back to Wakarusa at the end of October and plan to have them resolve the buzzing problem again. If you have add'l information to share I would appreciate it. It would be great if I could resolve this on my own.

By the way, I checked out your Diplomat modifications page and I really like how you setup the auxiliary monitor for Aladdin system. I may try to do that modification (among others you have) on our rig too.

Thanks, Bill

Robin_M · 09-03-2007, 02:05 PM

Bill,

Actually, I had forgotten about this thread when I asked that question in the other thread.

I don't have anything more to add other than what's been posted in this thread already.

In short, I'm fairly sure that the converter is NOT a necessary part of the fix, and in my case, caused a worse problem of it's own. I simply removed it along with it's harness. I left the switch box in place cutting the leads between it and the relay that actuated the "switch". All interference is gone for me now, however unfortunately I cannot tell you why. And because the switch box does not functon as a "switch" (without the relay in the ciruit) everything functions as it originally did. I can only guesss that there is some filtering going on in that switch box - or at least it is isolating the orginal source of the noise.

I was going to experiment some more with it, but haven't found the time. And truthfully, I don't really have the motivation to try other things, as the problem is solved for me and without the large converter in the cabinet taking up space.

Socal36 · 09-05-2007, 03:46 PM

Hey guys, I also have this problem. The local stealer err dealer... Couldnt fix the problem and said I just need to live with it after replacing the amp twice... With this thread printed I will be going back to smack that service managers dum **S over the head.

After reading alot of what you guys have posted, seems we all have alot of the same new coach problems...

Freemn2 · 09-05-2007, 05:37 PM

I also have that problem and have taken it to the dealer 3 times. I was told they couldn't isolate the problem. I read the "fix" and called Monaco. They confirmed the SB 07-07-08 and also told me they had posted the SB to my coach file and all the dealer had to do was call them with the problem. They would have confirmed the fix and sent the parts. That is being done now.

Bottom-line, (and what I will insist upon in the future), was that all the dealer had to do was contact Monaco and it would have been easily resolved. Dealers seem not to be anxious to make phone calls. ??? But it doesn't bother me to call them. Things get done when I do. Go figure?!

Robin_M · 09-05-2007, 05:55 PM

Quote:

Originally posted by Socal36:
After reading alot of what you guys have posted, seems we all have alot of the same new coach problems...

You're right, Mike. That's why it's always a good idea to get Monaco involved, as well as the dealer. The dealer's aren't always up on the latest fixes.

If you and Freemn2 are going to get the SB 07-07-08 kit installed, suggest you have them install the electronic switch first without the large converter box and see if that resolves the problem by itself. If it does, have them test it with and without the engine running. If all the noise is gone (as was the case in my coach) they can stop there and cut the harness wires leading to the relay. Then everything will work as it did before, only without the noise. (The default postion for the electonic switch is to use the amp. The relay switches the amp out of the loop when the ignition is on, but that may not be necessary.)

GoneFishin · 09-05-2007, 08:59 PM

Where can I find SB 07-07-08? We too have been trying to ignore the static, humming and interference coming from the speakers for the past 3 months. But it's time to deal with it now.
Thanks!

Robin_M · 09-06-2007, 04:16 AM

Quote:

Where can I find SB 07-07-08?

Your dealer should have the service bulletin by now. If not, you can always call Monaco customer service.

That said, I do not belive the "fix" described in this SB is the proper way to deal with this problem for reasons described earlier in this thread. I'd ask Monaco if they have a newer "fix" that does not involve the seperate 110v converter.

I don't believe the interference is coming in directly from the power supply. If I were trying to tackle this problem again, I'd first try what "loranimal" described early in this thread - running the RCA cables directly from the radio to the amp, bypassing the large A/V switch box. If that solves the problem, then that's where Monaco should be looking for a solution.

Murphee · 10-13-2007, 04:28 PM

We purchased an 07 Knight which has a Magnadyne AC12K2 suppressor between the batt. POS. + and the stereo by Magnadyne also. We were told by Daytona dealer that they replaced the stereo to get rid of the noticeable whistle AND buzz in a kitchen speaker, but if they did, the noise is simply different now but still present. And, if you turn the fader to FRONT, there is NO sound--only on REAR for all five speakers. Dealer says Monaco says "that's all normal--live with it." Plus, we hear there is a woofer in the wall in some RV's that is simply not connected--anyone know if that's standard in 'surround sound' systems?
And re the bad DVD player by Magnadyne--despite it being brand new and we've tried a variety of DVD's--the result is usually a long "LOADING" message on TV, followed by "NO DISC" repeatedly. Useless. Neighbor camper had same problem. Sounds like a magnadyne product problem. Anyone know more on this? I hesitate to run a cleaner through a new unit--never had to do that on older units after dozens of plays.