Home » Public Forums » GMCnet » Onan 4obf1r9000a 4 KW (Parts list for circuit board?)
| Onan 4obf1r9000a 4 KW [message #344133] |
Tue, 11 June 2019 12:35  |
Bob Solomon
Messages: 13
Registered: October 2013
Location: Torrance, Ca
Karma: 0
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Junior Member |
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Runs good but no power output, was told to change the circuit board, but I need a part # to cross referance. Help ?
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| Re: [GMCnet] Onan 4obf1r9000a 4 KW [message #344148 is a reply to message #344136] |
Tue, 11 June 2019 20:16  |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Bob,
You should go to our web site www.gmrvparts.com
There you'll find some of the usual parts and call us for tech questions.
On Tue, Jun 11, 2019 at 11:02 AM Bruce Hislop via Gmclist <
gmclist@list.gmcnet.org> wrote:
> The circuit board on the 4 & 6 Kw Power Drawers used in the GMC motorhome
> has nothing to do with AC power output, it only operates the engine.
> If the engine operates fine, then the board is good.
>
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Onan 4obf1r9000a 4 KW [message #344149 is a reply to message #344148] |
Tue, 11 June 2019 20:18 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Sorry, gmcrvparts.com
On Tue, Jun 11, 2019 at 6:16 PM Jim Kanomata wrote:
> Bob,
> You should go to our web site www.gmrvparts.com
> There you'll find some of the usual parts and call us for tech questions.
>
>
> On Tue, Jun 11, 2019 at 11:02 AM Bruce Hislop via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> The circuit board on the 4 & 6 Kw Power Drawers used in the GMC motorhome
>> has nothing to do with AC power output, it only operates the engine.
>> If the engine operates fine, then the board is good.
>>
>> --
>> Bruce Hislop
>> ON Canada
>> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
>> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
>> My Staff says I never listen to them, or something like that
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk@appliedairfilters.com
> http://www.appliedgmc.com
> 1-800-752-7502
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: Onan 4obf1r9000a 4 KW [message #344206 is a reply to message #344133] |
Fri, 14 June 2019 21:29 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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As Bruce mentioned in a previous posting the circuit board has nothing to do with generating electricity. The board controls motor starting and running only.
Ad far as repairing the board, I have repaired many of them. I finally decided that it was not worth my time to repair a 40 year old board that would soon fail again when another component failed or shorted. One relay in particular is no longer available and I had to jury rig a different one in place of it and change the values of several of the components associated with it to get it to work. I now suggest that you get a new aftermarket Dinosaur board from Jim K, change it in 5 or 10 minutes and be done with it.
Again, if your Onan starts and runs OK then your problem is on not the board.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Onan 4obf1r9000a 4 KW [message #344208 is a reply to message #344206] |
Sat, 15 June 2019 00:07 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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At the Fall Western States Rally,October 2-6 since I am the Techical VP, I
have asked Gary Bove to put on a Tech session on the Onan.
He will cover most every trouble shooting On the Onan Generator.
There will be few other topics presented as well.
Should there are anyone that might want to present some technical topic of
interest, please contact me.
On Fri, Jun 14, 2019 at 7:30 PM Ken Burton via Gmclist <
gmclist@list.gmcnet.org> wrote:
> As Bruce mentioned in a previous posting the circuit board has nothing to
> do with generating electricity. The board controls motor starting and
> running only.
>
> Ad far as repairing the board, I have repaired many of them. I finally
> decided that it was not worth my time to repair a 40 year old board that
> would
> soon fail again when another component failed or shorted. One relay in
> particular is no longer available and I had to jury rig a different one in
> place of it and change the values of several of the components associated
> with it to get it to work. I now suggest that you get a new aftermarket
> Dinosaur board from Jim K, change it in 5 or 10 minutes and be done with
> it.
>
>
> Again, if your Onan starts and runs OK then your problem is on not the
> board.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Onan 4obf1r9000a 4 KW [message #344209 is a reply to message #344208] |
Sat, 15 June 2019 00:18 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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You know we sell new Onan units as we are Cummins Onan Dealer, but
encourage people to keep the old one as we have at least 15 GMC owners that
are very sharp about these old units and are willing to help you to trouble
shoot. This kid of tech support is why I run the origional in my coach and
not the new model.
On Fri, Jun 14, 2019 at 10:07 PM Jim Kanomata wrote:
> At the Fall Western States Rally,October 2-6 since I am the Techical VP, I
> have asked Gary Bove to put on a Tech session on the Onan.
> He will cover most every trouble shooting On the Onan Generator.
> There will be few other topics presented as well.
> Should there are anyone that might want to present some technical topic of
> interest, please contact me.
>
>
> On Fri, Jun 14, 2019 at 7:30 PM Ken Burton via Gmclist gmclist@list.gmcnet.org> wrote:
>
>> As Bruce mentioned in a previous posting the circuit board has nothing to
>> do with generating electricity. The board controls motor starting and
>> running only.
>>
>> Ad far as repairing the board, I have repaired many of them. I finally
>> decided that it was not worth my time to repair a 40 year old board that
>> would
>> soon fail again when another component failed or shorted. One relay in
>> particular is no longer available and I had to jury rig a different one in
>> place of it and change the values of several of the components associated
>> with it to get it to work. I now suggest that you get a new aftermarket
>> Dinosaur board from Jim K, change it in 5 or 10 minutes and be done with
>> it.
>>
>>
>> Again, if your Onan starts and runs OK then your problem is on not the
>> board.
>> --
>> Ken Burton - N9KB
>> 76 Palm Beach
>> Hebron, Indiana
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk@appliedairfilters.com
> http://www.appliedgmc.com
> 1-800-752-7502
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: Onan 4obf1r9000a 4 KW [message #344210 is a reply to message #344133] |
Sat, 15 June 2019 08:38 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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So regarding your original problem of no AC power...
Common things to check are the breaker on top of the unit, exercise it and if you have a meter, meter on ACV 200V scale from the line as well as load side to chassis to rule out the breaker. If in fact no AC, next suspect is the bridge rectifier which is 4 diodes in one package. Easily removed and tested with Ohm setting if you understand the orientation. Be sure to mark wires and positions on bridge. Next would be worn brushes in need of replacement. If the above test good then you will need to meter the field winding leads to see if the windings have failed. There is a rare case where the unit has lost residuals magnatism from long disuse, but rule out all above first.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Onan 4obf1r9000a 4 KW [message #344216 is a reply to message #344133] |
Sat, 15 June 2019 14:16 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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The Onan circuit board isn't hard to repair, and the parts to do so are pennies. The only piece that's hard to find is K3, the run relay. It can be replaced with two small heathen chinee relays, one with the proper coil for the circuit which switches the second which has sufficient current capacity contacts. Nine out of ten, replacing the capacitors and the diodes, making sure there are no burnt runs on the PC board or repairing burnt ones will heal it. Teh tenth time, you end up replacing K3. The diodes were originally in glass envelopes which die in vibration and later epoxy envelopes which allow corrosion to eventually get to the wire inside the diode. A hundred cost me something under five dollars at Sky Craft a couple years ago. One of the capacitors was a dime, the other about 6 cents in quantity.
Occasionally the connectors on the wires and/or the blades on the circuit board need replacement, again they're cheeeep.
When you get done, paint the card both sides with conformal coating.
\--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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