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mque · 05-21-2015, 07:29 PM

Problem: My big boy relay is operational and charges both house and engine batteries, but does not disconnect when the voltage on both house and engine fall below 12.6 volts. The 12.6 came form Monaco. This means that my engine and house batteries will both discharge at the same rate all the way to zero volts. I believe that the circuit board 73-00-824-000 made by intellitec is probably bad.

Support information
I have checked my BB relay and it working fine. It engages and disengages when when you take away one of the two small wires that energize the BB relay. I checked the battery boost switch with my volt/ohm meeter and it working fine. All three power inputs, alternator/genset/Shore power, charge both House and Engine. My talk with Monaco left me a little confused when trying to order the new part. The tech people gave me Intellitec part number 73-00824-000. When I talked with Monaco's parts people they were not quite sure of the part number and said there had been some modifications to the 73-00824-000 circuit board and I would have to order an additional part to make it work due to these changes. But they did not know what the changes are.

Question:
Does anyone have any background on this or know what these changes are, and did Intellitec change the part number. Don't know what to order at this time. Can someone give me some background information and input. A source for the right part # if this number is incorrect would be very much appreciated as well.

DtBt · 05-21-2015, 08:40 PM

When I replaced mine last year I got a 74-00824-000 off ebay that worked perfectly without any additional parts. That number is from memory and I believe is correct. I will verify tomorrow.
The problem with mine was the PIC microcontroller ( the little 8 pin DIP) had a bad analog input and would cycle the BB relay on a 2 minute cycle. I pretty throughly investigated the problem. I am an EE with lots of design experience. Your symptoms are a little different but are probably a similar problem. If you replace the board, don't throw it away as I have been considering programming a new PIC for my bad board.
Check out http://www.ebay.com/itm/INTELLITEC-R...3D151280024928

mque · 05-22-2015, 09:06 AM

Thank you for the quick response. I finally got in touch with Intellitec tech support today. Your memory is perfect on the part #. Your diagnosis is on the money as well. The tech support person agrees with you that it is the board. He gave me a tip that I would like to run by you. On the board side 8 pin connector, number 1 and 8 pins both go to ground. He suggested the I cut those to wires hook them both to a #12 wire and run them to a solid ground like to run box or frame. I know there are more problems with grounds than almost anything else on 12V systems. However, I would be interested in your take on this before I did it. Thank you for the ebay link to the part. I will have to say I was surprised when the intellitec support person said he would sell me the 74-00824-000 for $91. I will keep my old board. I hope you can figure a way to salvage them. Thank you again very much for the quick support. It is really appreciated.

mque

DtBt · 05-22-2015, 07:24 PM

Glad you have a handle on your problem. I guess I paid too much for my board off ebay.
I would guess the failure of the analog input(s) could very well be a result of a transient. CMOS chips do not like inputs going below the chip ground. That RRB has several BIG relays and solenoids with likely huge EMF's that could easily effect the board ground. Beefing up the ground certainly could not hurt in any event but my schematics for the original board shows a ground on pin 1 but the battery kill switch signal on pin 8. I will check the gauge of the ground wire on pin 1. EMF suppression diodes directly across all of the solenoid coils might the useful as well.

YC1 · 05-22-2015, 08:04 PM

What yr is your RV? Posting model and yr helps us.

mque · 05-23-2015, 08:18 AM

I have a 2006 Monaco Dynasty, my over site.

My wiring diagram shows the same pin configuration. Pin 1 is a ground (looks like 16 or 18 gage wire, not very robust). Pin 8 also shows it to be the battery kill switch (not sure what this means). The tech from Monaco wanted me too add the ground to pin 8, and was not concerned with pin 1. Seems to me his concern would have been with pin 1 if your trying to protect the board.

Mike and Sharon
2006 Monaco Dynasty

DtBt · 05-23-2015, 03:37 PM

I think the Battery Kill switch, aka battery cutoff switch is a euphemism for the Salesman Switch but not positive. I cannot think of any other possibility.

mque · 05-25-2015, 01:26 PM

I agree and was thinking the same thing regarding pin 8. I know that the salesman switch is operated through that board because I pushed on of those mire buttons on the board and all the 12v lights in the coach went off. My wife said what happened to the lights. I thought Oh no what did I do now. But after thinking about it. I flipped the salesman switch and restored all (hero for one second). I need to talk with Intellitec again anyway about my circuit board delivery. I will try to get clarification on why they want me to take pin 8 to ground as well.

Mque