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Onan 12 MDJC - 3r/2268d (1985)


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  #21  
Old 08-03-2017, 07:57:21 PM
MBB MBB is offline
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

Here is another possibility. Could it be 12.0MDJC3CR2268AD or 12.0MDJC18R2268AD both use the same wiring diagram. OP can you tell how many wires come out of the generator end the "t wires" Is it 3, 4, or 12 ? They would be the ones feeding an outlet or supplying the power. Were trying to find the correct diagram. I believe though it is either the one KevinK posted or the one I posted. I thought I had read it was a 12 lead. I went back and read the thread again and it and didnt say anything about that, must have been another thread.
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Old 08-03-2017, 08:52:38 PM
JohnnyC JohnnyC is offline
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

sscummins, I received and replied to your PMs. Not sure if you read them yet. As for your control box, it will need a complete overhaul. It is not hard to do, but will take time and planning.

I had to redo my 15.0 JC's control box. Although it was not as bad as your box, none the less it had to be totally rewired. Since your genset is a diesel it has more wires when comparing my control box with yours.

As mentioned, make sure you have the proper schematic and wiring diagram(s) for your genset. Secondly, take LOTS of pictures during the entire rebuild. Take pictures from different view points too. Many times I see thing in my pictures that I missed by eye when at the control box. More picture the better. Make sure your picture are clear, not the typical Craiglists pictures that are blurry and worthless.

Just to show you my control box from start to finish, I attached 4 pictures below. The first 2 pictures show the damages in the control box and after removing most of the wires and components. The last 2 pictures show the end of reconstruction. I have several hundred pictures showing everything in between. By the way, my JC also started and ran with mouse piss and chewed wires. Onans are very resilient to lots of damage because they are built tough. Mouse piss could not destroy my JC and human piss could not stop my 4.0 BFA.


JohnnyC
New Jersey
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  #23  
Old 08-04-2017, 09:44:54 AM
sscummins sscummins is offline
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

Kevin K posted a wiring diagram, is that the correct one? or is MBB the correct posted one above?
Also, thats JohnnyC for great advise as with everyone one else. I cant thank all of you enough and I dont want to miss thanking anyone at all, so if I did forget, it was unintentional. JohnnyC where can I purchase all my components connectors for in the box?
Oh the wiring diadram I have is from an early=ier post to this thread. I tried going back when posting this one before but it erased all I typed and oh how I hate typing. I rather have grease on my finger tips then black keyboard. LOL
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Thanks not Thats JohnnyC
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  #24  
Old 08-04-2017, 12:15:49 PM
grif grif is offline
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

Quote:
Originally Posted by JohnnyC View Post
Secondly, take LOTS of pictures during the entire rebuild. Take pictures from different view points too. Many times I see thing in my pictures that I missed by eye when at the control box. More picture the better. Make sure your picture are clear, not the typical Craiglists pictures that are blurry and worthless.

JohnnyC
New Jersey
What on earth did we do before digital cameras? I use my phone non-stop for note taking during projects.

JonnieC: Do you slip the insulator off the ring connectors, solder then slide the insulators back on or actually depend on the crimp?
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Old 08-04-2017, 12:30:53 PM
JohnnyC JohnnyC is offline
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

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Originally Posted by grif View Post
What on earth did we do before digital cameras? I use my phone non-stop for note taking during projects.

JonnieC: Do you slip the insulator off the ring connectors, solder then slide the insulators back on or actually depend on the crimp?
I remove the plastic insulator from each connector, crimp the connector with the wire in it, solder the wire and connector, then use a glue sealer heat shrink tube over the crimped / soldered area of the connector. Overkill, but that is how I do things - The American way with pride, not the cheap-azz Chinese way.

JohnnyC
New Jersey
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  #26  
Old 08-04-2017, 03:17:47 PM
sscummins sscummins is offline
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

Can anyone know where to get the internal components for the control Box?

JohnnyC,

where can I find the parts to rebuild my control box?
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  #27  
Old 08-04-2017, 05:07:55 PM
JohnnyC JohnnyC is offline
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

Quote:
Originally Posted by sscummins View Post
Can anyone know where to get the internal components for the control Box?

JohnnyC,

where can I find the parts to rebuild my control box?
Onanparts.com, Ebay, Craigslist, Asking on this forum. There is a thread on this site titled "Onan Parting Out Thread" see link below.

https://www.smokstak.com/forum/showthread.php?t=99191

Lots of the work requires elbow grease as some parts may clean up.

Maybe if you are lucky, someone may be parting out an Onan 12 MDJC with a compatible control box in good condition and you can negotiate a deal. That will save you lots of time. For me, I simply rebuild them which is my therapy otherwise I go crazy bored . I rebuilt from ground up a control box for a 15.0 JC, 6.5 NH, 4.0 BFA and some work on a 15 RJC. If I can do it, so can you as some of my friends tell me I am retarded (or worse). Plan, take zillions of pictures, ask questions here and you will succeed.

JohnnyC
New Jersey
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  #28  
Old 08-04-2017, 05:10:29 PM
sscummins sscummins is offline
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

Thank you again.
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  #29  
Old 08-05-2017, 07:39:14 AM
Kevin K Kevin K is offline
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

Quote:
Originally Posted by sscummins View Post
Kevin K posted a wiring diagram, is that the correct one? or is MBB the correct posted one above?
You need to verify the wiring diagram with your generator. The single spec letter in the model number indicates a Magneciter generator, so I limited my search to those models. Mike assumed it may be a later model using an electronic voltage regulator, and he may be correct. Check your generator to see if it has a YD generator end and electronic voltage regulator( newer model) or a Magneciter (older model).
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Old 08-05-2017, 08:33:01 AM
Max Thompson Max Thompson is offline
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Default Re: Onan 12 MDJC - 3r/2268d (1985)

Quote:
Originally Posted by sscummins View Post
where can I find the parts to rebuild my control box?
I get mine from Allied electronics. Terminal strips and replacement relays & sockets. The link below has the part #s for the relays and sockets. Note the start disconnect / ignition relay has a 6-V coil. I use the 12-V relay to replace the start solenoid inside the box.

https://www.smokstak.com/forum/album.php?albumid=1428
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