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Onan Generators

Onan 7.5 JB's Recovery Towards A New Life


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  #261  
Old 02-14-2017, 02:14:55 AM
len k len k is online now
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Default Re: Onan 7.5 JB's Recovery Towards A New Life

Jim ..looks like a 10 turn pot ....for really fine adjustment.

Johnny..... from the YD manual r13 is a 1/4 watt 12k ohm resistor so a 2.5 k one might only have to be (2.5/12)*(1/4) =.05 watt.......throw in a 1/4 watt or higher , it's a standard size
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  #262  
Old 02-14-2017, 09:09:44 AM
Crankpot Crankpot is offline
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Default Re: Onan 7.5 JB's Recovery Towards A New Life

Quote:
Originally Posted by JohnnyC View Post
Crankpot, I am ready to disucss with you the big red Onan vinyl decal for the flywheel cover. The control box will be at a later date.

Do you need dimensions? Do you actually cut the vinyl decals? If you have the data file, will it load onto any software for cutting vinyl decals? How you we proceed?

Thanks,
JohnnyC
New Jersey
Tell me how wide you want the red onan logos. And how many etc. I'll make you the black genset word also to match. I can't make the numbers as my outline fonts are too thin and they won strip ( 6.0 7.5 etc). But I can send you numbers that match the genset font. Just let me know. I'll send you the image for the onan logo as well if you like. It's an .eps
I think. Pm me for details.

---------- Post added at 08:09:44 AM ---------- Previous post was at 07:59:22 AM ----------

Quote:
Originally Posted by Jim McIntyre View Post
No. I just used some random pot I had in my junkbox. It's not a high power thing - something like this would do nicely, I'd think:

http://www.ebay.com/itm/2-5K-OHM-2-W...kAAOSwjXRXcYSX
I'm doing this same mod to mine. But I can't find a pin out for these regulators and as such haven't hooked it up. The wiring diagrams I've found all use pins 1 2 and 3 for external pots. My regulator has the transformers connected to those terminals.

I have a jumper are this same terminals you connected your pot to and I'm assuming yours worked ok? I bought a 2k pot ($.30) on eBay but still waiting...
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  #263  
Old 02-14-2017, 12:02:34 PM
len k len k is online now
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Default Re: Onan 7.5 JB's Recovery Towards A New Life

Crankpot ....
Maybe your looking at reg package numbers (1 to 4, VS board numbers 1 to ~ 10??) , not reg circuit board numbers??
Read YD manual and look at it's schematic. Using a jumper instead of pot I believe jumper goes from pin 1 to pin 2.


Johnny ... likely won't be an issue for 20 years but throwing in another pot is another possible failure point. especially in a vibration environment.

If you do install one I'ld make it a wire wound type not a conductive plastic one (composite) . That wear test fixture I talked about was to subject a group of ~ 12 plastic pot elements to dither vibration. Pot was in an item that was also in a high vibration environment, hung under wing of an aircraft. But application subject the pot shaft to slight motion from vibration.

I wouldn't bother with optional pot. Once you adjust pot to voltage you want , your likely to never need to adjust it for many years. Only thing I see that will change voltage is long term aging of electronic components. Besides there's a second pot in reg that may eventually need adjustment too, sensitivity

Last edited by len k; 02-14-2017 at 02:36:04 PM.
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  #264  
Old 02-14-2017, 01:47:59 PM
JohnnyC JohnnyC is offline
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Default Re: Onan 7.5 JB's Recovery Towards A New Life

Too late Len. I bought a pot this morning. 2.5k 2 watt. I spent a few extra $$ for a high quality sealed pot. Made in Canada, maybe by Bigblocks relatives. Looks to be of high quality. The cheap Azz non sealed pots looked cheezy and stamped made in China. Pictures later. Eating lunch now.

JohnnyC
New Jersey
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  #265  
Old 02-14-2017, 02:37:18 PM
len k len k is online now
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Default Re: Onan 7.5 JB's Recovery Towards A New Life

My terminals 1, 2 were little corroded so I'll just solder a wire between them, and go without external pot for better reliability.

Last edited by len k; 02-14-2017 at 03:56:26 PM.
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  #266  
Old 02-14-2017, 06:21:41 PM
JohnnyC JohnnyC is offline
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Default Re: Onan 7.5 JB's Recovery Towards A New Life

I mounted the pot afterwork today. I did not wire it up. I just wanted to see how it will look and fit. Below are the pictures. Looks ok. I need to ask Jim a few questions which I will do later.

JohnnyC
New Jersey
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  #267  
Old 02-14-2017, 10:24:16 PM
JohnnyC JohnnyC is offline
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Default Re: Onan 7.5 JB's Recovery Towards A New Life

This evening I finished the installation of the external manual voltage adjustable control that mounts on the top of the control box voltage regulator. I won't be able to try it out until I finish the refurb on the JB which should be complete sometime in the year 2025 or later. Anyway, I attached 2 pictures (actually 4) showing the before next to the after. I tried to make it look OEM as much as possible, but since I never seen the factory option in pictures, I can only go by the drawings seen in the manual.

I assume it is a factory option, right? If so, does anyone know the option code?

JohnnyC
New Jersey
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  #268  
Old 02-15-2017, 11:04:06 AM
JSConan JSConan is offline
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Default Re: Onan 7.5 JB's Recovery Towards A New Life

By my options list,

K270 Voltage Adj. Rheostat
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  #269  
Old 02-15-2017, 11:00:41 PM
JohnnyC JohnnyC is offline
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Default Re: Onan 7.5 JB's Recovery Towards A New Life

Quote:
Originally Posted by Crankpot View Post
Tell me how wide you want the red onan logos. And how many etc. I'll make you the black genset word also to match. I can't make the numbers as my outline fonts are too thin and they won strip ( 6.0 7.5 etc). But I can send you numbers that match the genset font. Just let me know. I'll send you the image for the onan logo as well if you like. It's an .eps
I think. Pm me for details
Crankpot, I have the size information on the big red Onan logo as seen in the pictures below. I can take pictures with a ruler in each picture for the large print on the side of the control box this weekend. The control box is stored under a ton of crap in my workshop as I planned to work on the control box much later. Will the pictures below help??
Thanks,
JohnnyC
New Jersey
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  #270  
Old 02-16-2017, 09:24:33 PM
JohnnyC JohnnyC is offline
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Default Re: Onan 7.5 JB's Recovery Towards A New Life

Thursday Onan Therapy Session Update

This evening I am trying to get prepared for my next shooting of primer and paint for parts that were not painted this past weekend. Tonight I concentrated on the generator end bell cover tin and the starter. The starter was installed on the JB prior to painting and only half of it was painted. It never had primer so cleanup was easy. I attached a picture below of the cleaned up starter.

My tentative Onan Therapy sessions for this weekend are:

Saturday - Finish all paint removal on all parts except to the carburetor and fuel pump. I will need to rebuild these two parts on the side. Also excluded from this weekend's therapy sessions is the control box. I will total dismantle the wiring and components inside the control box and weld a plate in the right rear corner to prevent mice from entering. I will drill a hole just big enough to allow the wires to pass into/out of the control box. I did this to my ex- 15.0 JC 2 years ago. Almost forgot to mention that the main body of the JB (motor and generator) will be the main focus in the next week or two.

I will clean up the wprkshop and hang all parts to be painted by late evening.

Sunday - Prime and paint then goof off for the rest of the day.

JohnnyC
New Jersey
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