Author Topic: Fried multiplex board  (Read 1670 times)

Jon Wells

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Fried multiplex board
« on: May 26, 2023, 06:01:35 PM »
Our 2006 Monterey was getting some work done while we were off to visit our daughter and family in Kona Hawaii for two weeks.  We finally made it back to the service center last evening (Tuesday) expecting to find our coach in their minnie RV park.  It was not there.  We went over to the area just outside the service bays, and found it there.  I noticed right away that the coach had no power.  When I opened the door, one of the multiplex circuit boards was on the steps, and obviously charred.  The coach smelled like smoke.  I went into the bathroom where the circuit board came from, and could see that the wood behind where it was mounted had charred a bit.  Fortunately it was caught before it got any worse.  As it turns out, I missed an email from them on Monday (while we were flying back to Florida) telling me about the problem, so it was quite the nasty surprise.  They recently installed a replacement board.  I just spoke with our service coordinator, and found out they are having trouble getting things to work.  The coach is at the Lazydays in Wildwood Florida, which use to be a Monaco dealer.  They have an older tech from the Monaco days that will be looking at the system on Tuesday (after Memorial Day).  Right now, the lights on the switch panels light up, and stay lit. 
JWW
2006 Monterey Ventura 4, 37ft.
C9, 400HP

Eric Maclean

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Re: Fried multiplex board
« Reply #1 on: May 27, 2023, 02:30:36 PM »
Jon
Did the repair guys determine why the multiplex board burnt ( loose connection , over current . Etc.) Or did they just take it out and just replace it.
As I always taught my apprentices that computers don't die they are murdered the point being that unless you know what killed the first one the new part may suffer the same fate either instantly or over time when the conditions that caused the problem in the first place reoccur.

Did the coach have this problem or any related multiplex problems when you took it to them if not personally I would question what changed , is it possibly something their technician did that caused the board to burn.
Of course they'll never admit to it and in the end you'll bear the cost of the repair.
But if it wasn't caused by something the tech did then the question remains what caused it to burn that board and will it happen again with the real possibility of a fire that could burn the coach.


Hope this helps
And good luck
Eric

1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.

Jon Wells

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Re: Fried multiplex board
« Reply #2 on: May 30, 2023, 05:21:58 PM »
Hi Erik,

They did not determine what caused the problem, and just replaced the board.  I sent a picture of the board to my brother who was a design engineer for Eaton, specializing in power control and metering systems.  He felt that the design of the board was decent, however, since they did not use gold plated contacts he would expect that thermal runaway of the FET transistors like this could develop after about 10 - 15 years of service from contacts building up resistance (coupled with a large-ish load). 

Today is when they will have an older Monaco tech that is familiar with these systems work on getting things working.  Hopefully they will be able to fix it soon. 

Cheers,
Jon
JWW
2006 Monterey Ventura 4, 37ft.
C9, 400HP
The following users thanked this post: Joel Ashley, Eric Maclean

Eric Maclean

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Re: Fried multiplex board
« Reply #3 on: May 31, 2023, 01:32:48 AM »
Hope it works out alright
Eric
1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.