Home Entertainment Sys Hum and SB 07-07-08

[LewF]

Has anyone had Service Bulletin 07-07-08 installed and if so what is the experience with the result.

This service bulletin applies to a number of 2007 Monaco, Holiday Rambler and Safari coaches and is meant to eliminate the hum in the home entertainment system. I have read the bulletin and it installs a converter and switch box into the system which appears to power the system without the inverter and give a more pure 60 cycle power supply. My inverter/charger is a model that does not produce a pure sign wave so I assme that this is the source of the hum as the system is currently configured.

I want to get rid of the hum but this modification installs two more boxes in the driver's side overhead and makes a lot more heat so I don't want to do it unless it works well.

Thanks for the help.

Lew

[UPS 34]

I have had that done. It includes a 12v box to power the system. I understand there is a better fix for this now. The power supply is big and takes up alot of space. It also gets hot. I would not have this installed. I am going to try to get the new fix.

[Robin_M]

Lew,

I've had it done. The converter caused other noise problems so I removed that part of it, and the original hum was still gone. Recently I also removed the switch box, and connected things back the way they originally were, and the hum was still gone. I believe, when my dealer installed this "fix" that he also installed a couple of new in-line RF filters, which is actually what resolved the problem for me. I now have in-line filters in the 12v power leads to both the home amp, and the Winegard switch box and I believe there is also one on the audio output from the radio. No more hum. I will be at the dealer later this week and I'll try to determine exactly what it was they did.

There was a long thread on this subject last year. It may give you more info.

(Updated information below.)

[LewF]

Based on UPS 34 and Robin M's replys I am not going to have this mod installed. If either of you find out more about a new fix (UPS 34) or what type of filters were installed in the 12V supply (Robin M) I would appreciate it.

Thanks for the help to this point. Also thanks for the link to the thread on this subject.

Lew

[Robin_M]

Quote:

I've had SB 07-07-08 installed. The converter caused other noise problems so I removed that part of it, and the original hum was still gone. Recently I also removed the switch box, and connected things back the way they originally were, and the hum was still gone. I believe, when my dealer installed this "fix" that he also installed a couple of new in-line RF filters, which is actually what resolved the problem for me.

Update on my post here... I was at the dealer yesterday and I asked the technician who resolved my hum how he did it. He said he installed the Monaco Kit because that's what Monaco wanted him to do, but he thought the hum sounded like it was resulting from a ground loop in the audio. So on his own, he installed two "Ground Loop Isolators", one in each audio channel between the radio and the home theater amp. I have since removed all components of the Monaco kit, and left the ground loop isolators in place, and they have eliminated the hum.

The technicion said that these isolators are available at most electronic supply houses - probably at Radio Shack. He also needed gender adaptors for the audio cables to go with the ground loop isolators.

Lew, I was wrong about the dealer installing filters in the 12v supply. There are filters there, but they must have been originally installed by Monaco. It was the addition of Ground Loop Isolators in the audio lines that resolved the problem for me.

[Greg from Almanor]

Just thought that I would add to the confusion here. I have a '07 Cayman with the "Hum problem". I am scheduled in the fall to get into Harrisburg for the usual "fixes, tweaks, adjustments" and so on. So, I thought that I would wait until then for the audio doctors. But the Magnadon't, I mean Magnadyne quit. Would play as a radio but would not accept any disc, CD or DVD. I called Monaco and convinced them that I am perfectly capable and willing to swap the unit if they would send a replacement. They did! Try that with your new Ford. Call Dearborne and ask for a new radio! Anyway, when I pulled the unit out it had already installed what Robin just described. Ground loop isolators and a inline noise filter. I left them in place with the new unit. Still have the same hum but the disc player functions. Maybe I should try eliminating them and see what happens. I believe that these devices were installed by the dealer because one of the issues I had before acceptance was a loud clicking sound in the system when running the generator. By now, with all of the complaints I read here, one would think that Monaco would come with a bullet-proof solution.

[joelsr]

I had this mod installed according to the TSB. The Iota generates an inordinate amount of heat which can't be dissipated in the compartment. Also the Iota induces noise which messes up the tv recept. After the install was completed the hum was still present and you would have to use one of the o/h switches if on road and the other if on shore power. In addition my sat converter had to be moved to the opposite compartment. I've finally unplugged the Iota (15 amp battery charger). I'm going to ask the repair facility to put it back to original state. This is, at best, a Rube Goldberg fix that doesn't work. The repair facility has no choice other than to follow the TSB.

[Lukeaa]

I just had the fix installed last week and after reading the above, I am afraid to turn it own. Maybe next week.

[MonacoMama]

joelsr...
where did you have your "fix" done?

[AreWeThere]

Had my fix done back on May 13 at the Wildwood facility, but it didn't work. This past weekend May 24 one of the noise suppressor modules (small black boxes in the overhead cabinet) caught fire and would have burnt the coach down, but I just happened to walk in at the right time. I smelled plasic burning and looked at the cabinet and saw smoke coming out, I opened it and was able to remobe the module before it had time to do any damage. Thank God my kids were not in there asleep at the time.
I called Wildwood yesterday and they have set an appointment for June 12th to have it worked on again. Just a little scared with 2 small children sleeping in there.

[MonacoMama]

AreWeThere..
I am glad to there you were around and found the fire in time. This is a good reminder to anyone who has had THAT particular fix done...to not leave the coach unattended when you have the stereo on and those suppressors are powered on.
More importantly - Maybe NOW Monaco will find an actual cure for this stupid problem. This incident makes it a little more than an "entertainment" issue!

I'm glad everyone is safe & unharmed
Please keep us informed...

[AreWeThere]

Sacs,
I will get pictures today when I get home. The part that caught fire was one of the two black boxes you are referring to.
Photos:

[MonacoMama]

Yeouch...
Sacs...I don't think we have ever had that type of "black box"


MM

[AreWeThere]

The amp is under the wood box that is under the switch box. The blue wire does look as if it was cut, I don't know if it shorted out or not because I just grabbed a hand full of wires and yanked them out and then disconnected the suppressor.