Originally Posted by rdsamp
Thanks for any help you can give. With the help of this forum I have been able to find I had a fault 3.1.1, I also found mention of magnet pieces in the case. My water pump belt looks new. I believe I have a dead armature and need to replace same. I am wondering if I will need a new stator since the armature seems to have come apart? any of you who can give me advice on removal and replacement of the armature and tips for diagnosing the stator will have my thanks for as long as my failing memory lasts.
Onan QD 7500 1999 manufacture HDKAJ.
Options: A223, B402, L045, P090, R086
Wire Diagram 611-1236
A few items here. #1, Just what is the code "311"? #2, "...I have also found MENTION of magnet pieces in the case." Is this something that you read of, based on the word "mention" or, did you actually FIND pieces of magnet in YOUR generator housing? You also say your water pump looks new. Does this mean you've had the encompassing shrouding off of your 7.5QD? May I ask, what makes you believe you have a "dead armature"?
And by the way, just in case you actually DO have a bad one, it's referred as a ROTOR when you start looking for parts for the QD. If, IF, you have experienced the "disintegrating magnet" syndrome as some of us have, it will more than likely have damaged the interior of the stator. That rotor, operates, as you may or may not know, at about 1/16th" away from that stator. So, if and when, one of the seven magnets self launch, the potential for damage is about 99.9%, based on the ultra close proximity to the stator. Below are pictures of mine after disassembly. I could tell you a very, very long story here about how I came about finding the pieces of magnet and, what followed. But, I'll make it a short version.
First, we purchased this coach, an '04 Itasca Horizon 36GD with the C-7 330HP CAT back in May of '11. The gen at the time, had only 65 hours on it. We'd camped and used it for many hours after purchase. But, during one trip when it was warm out and we wanted the house air on, we fired up the gen and turned the air on. All went well, FOR ABOUT 5 MINUTES. Then it shut down. I fired it up again, turned the air on and, it ran for about 5 minutes and shut down. Well, it turned out to the infamous "temp sensor" that many of us have had issues with.
So, while me and a buddy were doing a check out of the gen while camping and had the top panel off, I found what looked like, dark gray hair, in clumps all over the inside of the housing of that gen. It was odd though. It would "stick" to vertical surfaces. I thought "What the heck" and would pull some off and found out it was magnetic material. I had no idea what that was all about.
Well, after some investigation and deeper inspection, it was determined that one of the 7 magnetic pads, which are glued to the flywheel/rotor, had released its glue and, had blown apart and disintegrated into a zillion pieces, all over the inside of that gen. But, the odd thing was, I have no idea when that happened. As stated, that gen had been operating just fine, 'till the sensor went out. So, I waited 'till we got home to do all the surgery on it.
It's quite an undertaking to break that gen all the way down, to gain access to that rotor and stator. It's really not hard nor is there a need for special tools, it's just intense. Well, as far as damage to my stator, yep, it did but, based on my judgement at the time, I simply replaced the rotor, anticipating the gen would run ok with that minor damage. When I got it all back together, it did run just fine and, even put out 120VAC without issue. But, I developed other operational issues later so, I went on the prowl for a new stator.
Back when I was looking for a rotor, I found out the part number and placed it on Ebay and other search medias. I had one pop up on Ebay and it was for an 8,000 watt version. I enquired to the seller of its condition and, whether or not there would be issues installing it on a 7.5QD. He assured me it was in flawless condition and, also that there was no issues installing that one on a 7.5.
I purchased it and had it shipped to my door for $200.00 That was a great deal. Now, when it came time for me to find a stator, no such luck. I had to purchase a brand new one.
That was a whopping $1,100.00, shipped to my door. It is what it is. I now have a new temp sensor, new coolant, new head gasket (long story on that), and a semi-new rotor and brand new stator. The gen is operating just fine. There's a lot more to this story but, that's the short version.
The really, really good part about mine is, IT'S ON A SLIDE OUT TRAY so, that made for waaaaaay easier in performing the necessary surgery on it.
P.S. Below are pics of: The damaged rotor, the damaged stator, the evidence of magnet exploding and you see pieces stuck to much of the stator. There's also pics of the stator mounted and unmounted on the engine.