4K Onan Bridge Rectifier

T

timthenomad

Member
Oct 23, 2015
85
12
8
Philadelphia PA
Hi All,

The 4K Onan in my Birchaven stopped producing AC current recently. After reading a lot of old posts, it seems there's a good chance it is the bridge
rectifier. So I ordered up one of the newer "twist the pins" replacements. I have downloaded the manual and the schematics show where is relatively,
but don't seem to offer much in terms of how one is to get at it.

Can I do the R&R with the generator still in the coach?

Thanks

Tim
--
Tim Taylor
Austin TX
76 Birchaven (SB)
76 Triumph TR6
 
Just pop off the plastic grill.
Call me and I'll walk you through.

> Hi All,
>
> The 4K Onan in my Birchaven stopped producing AC current recently. After
> reading a lot of old posts, it seems there's a good chance it is the bridge
> rectifier. So I ordered up one of the newer "twist the pins"
> replacements. I have downloaded the manual and the schematics show where
> is relatively,
> but don't seem to offer much in terms of how one is to get at it.
>
> Can I do the R&R with the generator still in the coach?
>
> Thanks
>
> Tim
> --
> Tim Taylor
> Austin TX
> 76 Birchaven (SB)
> 76 Triumph TR6
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
Read here
http://bdub.net/gmcmotorhome.info/generator.html

On Wednesday, September 14, 2016, Jim Kanomata
wrote:

> Just pop off the plastic grill.
> Call me and I'll walk you through.
>
> On Wed, Sep 14, 2016 at 12:35 PM, Tim Taylor
> > Hi All,
> >
> > The 4K Onan in my Birchaven stopped producing AC current recently. After
> > reading a lot of old posts, it seems there's a good chance it is the
> bridge
> > rectifier. So I ordered up one of the newer "twist the pins"
> > replacements. I have downloaded the manual and the schematics show where
> > is relatively,
> > but don't seem to offer much in terms of how one is to get at it.
> >
> > Can I do the R&R with the generator still in the coach?
> >
> > Thanks
> >
> > Tim
> > --
> > Tim Taylor
> > Austin TX
> > 76 Birchaven (SB)
> > 76 Triumph TR6
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
>
>
>
> --
> Jim Kanomata
> Applied/GMC, Fremont,CA
> jimk
> 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
>

--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://bdub.net/gmcmotorhome.info/
Alternator Protection Cable
http://bdub.net/gmcmotorhome.info/APC.html
 
Tim,

In spite of what has been posted, do not be surprised if you can not get at it. It may be different in later BFs, but in my 73 - 23 it can not be
done. I also have a real struggle to get the cover off the control board.

I suggest that you get the older manual that covers the BF (4.0) X7425. It can be downloaded. Removal of a BF is different than a NH(6.0) and if you
try to do it that way, you will end up in a bind.

You do not need to fully disconnect the unit, just the supporting mounts need be set loose so you can pull the BF clear of the coach and make access
to the bridge simple.

Matt

> Hi All,
>
> The 4K Onan in my Birchaven stopped producing AC current recently. After reading a lot of old posts, it seems there's a good chance it is the
> bridge rectifier. So I ordered up one of the newer "twist the pins" replacements. I have downloaded the manual and the schematics show where is
> relatively, but don't seem to offer much in terms of how one is to get at it.
>
> Can I do the R&R with the generator still in the coach?
>
> Thanks
>
> Tim

--
Matt & Mary Colie - Members GMCMI, GMCGL, GMCES
'73 Glacier 23 - Still Loving OE Rear Drum Brake with Applied Control Arms
Now with both true Keyless and remote entry
SE Michigan - Twixt A2 and Detroit
 
The early coaches varied a lot - my 73, 23 ft is earlier production than Matt's but I had no real problem removing the rectifier for testing.
Just be aware of debris falling into eyes/face.

Dennis

> Tim,
>
> In spite of what has been posted, do not be surprised if you can not get at it. It may be different in later BFs, but in my 73 - 23 it can not be
> done. I also have a real struggle to get the cover off the control board.
>
> I suggest that you get the older manual that covers the BF (4.0) X7425. It can be downloaded. Removal of a BF is different than a NH(6.0) and if
> you try to do it that way, you will end up in a bind.
>
> You do not need to fully disconnect the unit, just the supporting mounts need be set loose so you can pull the BF clear of the coach and make
> access to the bridge simple.
>
> Matt
>
>
>

> > Hi All,
> >
> > The 4K Onan in my Birchaven stopped producing AC current recently. After reading a lot of old posts, it seems there's a good chance it is
> > the bridge rectifier. So I ordered up one of the newer "twist the pins" replacements. I have downloaded the manual and the schematics show where
> > is relatively, but don't seem to offer much in terms of how one is to get at it.
> >
> > Can I do the R&R with the generator still in the coach?
> >
> > Thanks
> >
> > Tim

--
Dennis S
73 Painted Desert 230
Memphis TN Metro
 
> Hi All,
>
> The 4K Onan in my Birchaven stopped producing AC current recently. After reading a lot of old posts, it seems there's a good chance it is the
> bridge rectifier. So I ordered up one of the newer "twist the pins" replacements. I have downloaded the manual and the schematics show where is
> relatively, but don't seem to offer much in terms of how one is to get at it.
>
> Can I do the R&R with the generator still in the coach?
>
> Thanks
>
> Tim

I just did the bridge rectifier in my 6KW Onan and it is a tight fit, but doable. We did my neighbors 4KW a few years ago and that was also a tight
fit but doable. You need to make sure and mark the + and - wires and where they go as well as both AC wires and where they go. The new bridge
rectifiers are a different pin configuration from what came from the factory. I modified and kept the plastic holder.

I was happy that the cause of my losing AC power to run my roof air during the Woodward Dream Cruise was the bridge and not something other then the
failure of the 41 year old rectifier.

--
Richard
76 Palm Beach
SE Michigan
www.PalmBeachGMC.com


Coop Roller Cam 455, Howell TBI + EBL, 3.42 FD, Quadra Bag, Macerator, Manny Tranny etc.
 
I replaced mine in the coach ok. 73 model too.

----- Original Message -----
From: "Matt Colie"
To: gmclist
Sent: Wednesday, September 14, 2016 7:08:51 PM
Subject: Re: [GMCnet] 4K Onan Bridge Rectifier

Tim,

In spite of what has been posted, do not be surprised if you can not get at it. It may be different in later BFs, but in my 73 - 23 it can not be
done. I also have a real struggle to get the cover off the control board.

I suggest that you get the older manual that covers the BF (4.0) X7425. It can be downloaded. Removal of a BF is different than a NH(6.0) and if you
try to do it that way, you will end up in a bind.

You do not need to fully disconnect the unit, just the supporting mounts need be set loose so you can pull the BF clear of the coach and make access
to the bridge simple.

Matt

> Hi All,
>
> The 4K Onan in my Birchaven stopped producing AC current recently. After reading a lot of old posts, it seems there's a good chance it is the
> bridge rectifier. So I ordered up one of the newer "twist the pins" replacements. I have downloaded the manual and the schematics show where is
> relatively, but don't seem to offer much in terms of how one is to get at it.
>
> Can I do the R&R with the generator still in the coach?
>
> Thanks
>
> Tim

--
Matt & Mary Colie - Members GMCMI, GMCGL, GMCES
'73 Glacier 23 - Still Loving OE Rear Drum Brake with Applied Control Arms
Now with both true Keyless and remote entry
SE Michigan - Twixt A2 and Detroit

_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
We have done the 4k and 6k the same way.
Never need to dismount the unit.

> I replaced mine in the coach ok. 73 model too.
>
> ----- Original Message -----
> From: "Matt Colie"
> To: gmclist
> Sent: Wednesday, September 14, 2016 7:08:51 PM
> Subject: Re: [GMCnet] 4K Onan Bridge Rectifier
>
> Tim,
>
> In spite of what has been posted, do not be surprised if you can not get
> at it. It may be different in later BFs, but in my 73 - 23 it can not be
> done. I also have a real struggle to get the cover off the control board.
>
> I suggest that you get the older manual that covers the BF (4.0) X7425.
> It can be downloaded. Removal of a BF is different than a NH(6.0) and if
> you
> try to do it that way, you will end up in a bind.
>
> You do not need to fully disconnect the unit, just the supporting mounts
> need be set loose so you can pull the BF clear of the coach and make access
> to the bridge simple.
>
> Matt
>
>
>

> > Hi All,
> >
> > The 4K Onan in my Birchaven stopped producing AC current recently.
> After reading a lot of old posts, it seems there's a good chance it is the
> > bridge rectifier. So I ordered up one of the newer "twist the pins"
> replacements. I have downloaded the manual and the schematics show where is
> > relatively, but don't seem to offer much in terms of how one is to get
> at it.
> >
> > Can I do the R&R with the generator still in the coach?
> >
> > Thanks
> >
> > Tim
>
>
> --
> Matt & Mary Colie - Members GMCMI, GMCGL, GMCES
> '73 Glacier 23 - Still Loving OE Rear Drum Brake with Applied Control Arms
> Now with both true Keyless and remote entry
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
> Tim,
>
> In spite of what has been posted, do not be surprised if you can not get at it. It may be different in later BFs, but in my 73 - 23 it can not be
> done. I also have a real struggle to get the cover off the control board.
>
> I suggest that you get the older manual that covers the BF (4.0) X7425. It can be downloaded. Removal of a BF is different than a NH(6.0) and if
> you try to do it that way, you will end up in a bind.
>
> You do not need to fully disconnect the unit, just the supporting mounts need be set loose so you can pull the BF clear of the coach and make
> access to the bridge simple.
>
> Matt

Apparently there were lots of variations in the way the older coaches were configured. As I recall we had no difficultly accessing the rectifier when
I helped diagnose a no AC output problem with my former neighbors '73 23' Canyon Lands. As it turned out someone else had replaced the rectifier.
Here is a photo of his bridge rectifier. The plastic socket had been discarded.

http://www.palmbeachgmc.com/images/onan0167.jpg

--
Richard
76 Palm Beach
SE Michigan
www.PalmBeachGMC.com


Coop Roller Cam 455, Howell TBI + EBL, 3.42 FD, Quadra Bag, Macerator, Manny Tranny etc.
 
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