Home » Public Forums » GMCnet » Onan Control Board Question
| Onan Control Board Question [message #213987] |
Wed, 10 July 2013 23:27  |
bhayes
Messages: 263
Registered: March 2010
Karma: 1
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Senior Member |
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Greetings, everyone. First, a question: Does anyone know what a modern replacement part is for the Onan control board rectifier? It looks like a transistor and is described in the Onan Operator Manual on page 37, ref. 22, part 364-0011, as "Rectifier, Gate Control (8 Amp., 30 Volt). I have a bad Dinosaur control board board that uses a 2n5061 rectifier, though that part's specs are 60 volts and 10 amp surge rating. A 2n5060 seems closer to the original at 30 volts. The rectifier on my original control board is broken, but if I can find a suitable replacement, I should be able to muster some latent soldering skills from my childhood to put a new one in place.
And why am I asking this question? After having battled with my coach's temperamental Onan for years, it recently dug in its heels and refused to even consider starting. I threw several parts at it over the years, including swapping the control board with a Dinosaur board a few years ago. But after it recently folded its arms and shook its head at me when I pleaded with it to start, I finally decided to send the carburetor off to Walbro to have it rebuilt. Fortunately, they found and corrected several problems.
So I installed the newly rebuilt carb on the beast. It apparently was pleased because it happily fired right up. I ran the Onan for several hours with the A/Cs running, and it worked perfectly. Problem solved, I thought. Cautious optimism took hold, and we began planning our next weekend adventure (only our third in three years, unfortunately).
Now this next tale in the saga may have been pure coincidence. I was running the Onan last night while replacing the old and busted rear clearance lights with new and clever LEDs, and it was happily purring like a big kitten. When I finished for the evening, I innocently switched off the marker lights, and the Onan, apparently sensing that I was finally finding some satisfaction with the GMC, immediately shut down and refused to start. Same story as many of you have had--it cranks and fires up while holding the start switch down, but immediately shuts down when the switch is released. Whether or not it's somehow related to turning off the marker lights, I can't say.
I pulled the control board cover and jumpered terminals 5 and 9. The creature stirred and briefly mocked me, but finally threw up a white flag of surrender and came back to life. I unjumpered and jumpered the terminals a few times with the same results. Bad Dinosaur board again, it appears. But in a moment of daring, I dug out my old control board, hooked it up, and found that it ran the Onan just fine. I noticed, though, that the rectifier is missing half of its outer casing, which may have contributed to the problems I had with it before.
So that's the next chapter in my continuing saga of the ornery Onan.
Bryan Hayes
'76 Eleganza II
Salt Lake City, Utah
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| Re: Onan Control Board Question [message #213990 is a reply to message #213987] |
Thu, 11 July 2013 00:16  |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Senior Member |
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Replacing a rectifier with a higher voltage and ampere rating is a good thing. Replacing all the diodes in the original board is a good idea also use higher ratings.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: Onan Control Board Question [message #213991 is a reply to message #213990] |
Thu, 11 July 2013 01:13 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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One GMCer out of KY or Texas had a problem blowing Dinosaur boards. We (actually he) sent them back and Dinosaur built him a modded board and shipped it out. To my knowledge he has not had a problem since. I'll let him hop in here and give you his name and details.
If he doesn't, then call Dinosaur direct and tell them your problem and that there is a mod available. They did not charge him to fix / replace the board. He had gone through 3 of them. You could return the board to the retailer where you bought it but you will receive a new duplicate unmodified board.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Onan Control Board Question [message #214064 is a reply to message #214011] |
Thu, 11 July 2013 16:32 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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I was a little intentionally a little sketchy on who it was. Then I remembered your posting so I handed out your name and correct location.
There is nothing wrong with sending it back to Jim but if you want the update on your new board I would contact Dinosaur direct.
Jim definitely will help you out.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Onan Control Board Question [message #214101 is a reply to message #214100] |
Fri, 12 July 2013 00:05 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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| jimk wrote on Thu, 11 July 2013 23:59 |
We do not ask for proof of purchase or all that insulting questions.
We send out a ne one n/c and ask ou to return the defective one.
If you ask, we will send you a pick up tag so you do not need to pay the
return.
On Thu, Jul 11, 2013 at 2:32 PM, Ken Burton
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See, I told you that Jim would definitely help you out.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Onan Control Board Question [message #214391 is a reply to message #213987] |
Mon, 15 July 2013 00:01 |
bhayes
Messages: 263
Registered: March 2010
Karma: 1
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Senior Member |
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Thanks for the responses, everyone. I've been in contact with Dinosaur and we're looking into the problem. There is definitely a resistor on the board that is burned, and I've mentioned the repair they made to George Zhookoff's board.
I also replaced the damaged rectifier on my Onan's original board, soldered a few loose wire posts back into place, and successfully ran the generator with it for several hours. At the very least, I have a spare board now.
I'll keep everyone posted on how things go with Dinosaur. They're a good group to work with, and seem anxious to get my board's problems resolved. And to JimK, thanks for the offer on replacing the board. It's always a pleasure working with you and your team, and I'll let you know if I need to replace it.
Bryan Hayes
'76 Eleganza II
Salt Lake City, Utah
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| Re: [GMCnet] Onan Control Board Question [message #214407 is a reply to message #214391] |
Mon, 15 July 2013 07:03 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Soldering the loose posts seems to cure most of the problems with the original boards. On Stick's, we ran stranded wire thriough the post mount
holes and soldered it to both sides, giving s good connection to both the post and the PC run which has some 'give' to it for vibration. I've done this to the ones in our remote stuff for many years.
I noticed the conformal coating was gone on his, and there was consequently some erosion of a couple of the runs. These boards carry relatively high current here and there, any place the run is compromised ought to have a bridge across the bad spot. General Cement part # 22-203 is a good conformal coating, clean the board up with alcohol and a soft brush, then recoat it, making sure you >don't< get the coating varnish on the connector blades.
--johnny
'76 23' teransmode norris
'76 palm beach
--------------------------------------------
On Mon, 7/15/13, Bryan Hayes <hayesnet1@gmail.com> wrote:
Subject: Re: [GMCnet] Onan Control Board Question
To: gmclist@temp.gmcnet.org
Date: Monday, July 15, 2013, 5:01 AM
Thanks for the responses, everyone. I've been in contact
with Dinosaur and we're looking into the problem. There is
definitely a resistor on the board that is burned, and I've
mentioned the repair they made to George Zhookoff's board.
I also replaced the damaged rectifier on my Onan's original
board, soldered a few loose wire posts back into place, and
successfully ran the generator with it for several hours. At
the very least, I have a spare board now.
I'll keep everyone posted on how things go with Dinosaur.
They're a good group to work with, and seem anxious to get
my board's problems resolved. And to JimK, thanks for the
offer on replacing the board. It's always a pleasure working
with you and your team, and I'll let you know if I need to
replace it.
--
Bryan Hayes
'76 Eleganza II
Salt Lake City, Utah
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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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| Re: [GMCnet] Onan Control Board Question [message #214450 is a reply to message #214407] |
Mon, 15 July 2013 11:56 |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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Senior Member |
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| Johnny Bridges wrote on Mon, 15 July 2013 07:03 |
Soldering the loose posts seems to cure most of the problems with the original boards. On Stick's, we ran stranded wire thriough the post mount
holes and soldered it to both sides, giving s good connection to both the post and the PC run which has some 'give' to it for vibration. I've done this to the ones in our remote stuff for many years.
I noticed the conformal coating was gone on his, and there was consequently some erosion of a couple of the runs. These boards carry relatively high current here and there, any place the run is compromised ought to have a bridge across the bad spot. General Cement part # 22-203 is a good conformal coating, clean the board up with alcohol and a soft brush, then recoat it, making sure you >don't< get the coating varnish on the connector blades.
--johnny
'76 23' teransmode norris
'76 palm beach
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Johnny,
It is always nice to have options. And Jim K is a good one for replacement boards. But how willing would you be to evaluate Onan boards for GMCers?
What I am thinking is USPS postage for a small box is cheap. Someone could send you a board in a well packed/protected package for next to nothing. You could look at it and estimate cost to repair and advise the owner (with options, like slathering with conformal coating). If he agrees to the price, you fix the board, he sends you money (to include return shipping) and you send it back to the owner.
Everyone needs to understand there is no warranty.
If the owner doesn't want to pay that much, he can either tell you to keep/dispose of the board, or he can arrange to get it back in the condition you received it.
What do you think? Is it likely that shipping both ways, plus repairs, would be cost effective?
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| Re: [GMCnet] Onan Control Board Question [message #214502 is a reply to message #214450] |
Mon, 15 July 2013 17:33 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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>If< folks will be reasonable (three or four on hand at the time) I don't mind healing them up for a freebie. That way, if it doesn't work, you've lost nothing but a bit of time. The relays might run to some money - twenty bux maybe - but beyond that the parts are basically nickel items. I have bench stock on most of them. The two three terminal diodes want some looking at. One is an SCR, fairly easy to source, and I expect the other is actually some flavor of transistor. Again, if it can be found or replaced with a newer component, not a great problem. I look on it as a 'pay it forward', people on this list have helped me out and saved me a modest fortuna over the last year and a half. So let's give this a try:
1. The GMCer in/near Orlando who asked about this last Fall gets first if he's still interested (lost all my emails in a change)
2. No charge, but also no guarantees. (If it doesn't work now, all you're out is time)
3. Send to me in the Small UPS Box, and pad it with something... crushed newsprint, bubble, whatever.
4. Whatever the Postal Orifice wants to send it, include that much in stamps so I can send it back. (The boxes are free, I got them)
5. >don't< disconnect the wires from the board, disconnect the Molex (square white connector) and send the 'pigtail' of wires with the board.
6. Be sure to include name and mailing address so you get it back.
7. BE REALISTIC! If the board looks like a charcoal briquette, call one of our suppliers and pop for a new or rebuilt.
On that basis, if the gent in Orlando will reply here and send one or two of his to
Johnny Bridges
4029 Tanner's Mill Road
Braselton, GA 30517-1111
I'll get started and we'll see how this works out. If he doesn't want to, how's to post and say so, and A gets next.
--johnny
'76 23' transmode norris
'76 palm beach
--------------------------------------------
On Mon, 7/15/13, A. <markbb1@netzero.com> wrote:
Subject: Re: [GMCnet] Onan Control Board Question
To: gmclist@temp.gmcnet.org
Date: Monday, July 15, 2013, 4:56 PM
Johnny,
It is always nice to have options. And Jim K is a good
one for replacement boards. But how willing would you
be to evaluate Onan boards for GMCers?
What I am thinking is USPS postage for a small box is
cheap. Someone could send you a board in a well
packed/protected package for next to nothing. You
could look at it and estimate cost to repair and advise the
owner (with options, like slathering with conformal
coating). If he agrees to the price, you fix the
board, he sends you money (to include return shipping) and
you send it back to the owner.
Everyone needs to understand there is no warranty.
If the owner doesn't want to pay that much, he can either
tell you to keep/dispose of the board, or he can arrange to
get it back in the condition you received it.
What do you think? Is it likely that shipping both
ways, plus repairs, would be cost effective?
--
'73 23' Sequoia For Camping
'73 23' CanyonLands For Sale
UA (Upper Alabama)
"Time is money. If you use YOUR time, you get to keep
YOUR money."
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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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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| Re: [GMCnet] Onan Control Board Question [message #214518 is a reply to message #214502] |
Mon, 15 July 2013 19:12 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Johnny,
I went through all that parts substitution exercise back in 2001. The last
page of the Onan manual at bdub.net is my redrawn schematic, with all the
needed part numbers. It's labelled "4 kW", but only because that's what I
had -- 6 kW is identical.
Ken H.
On Jul 15, 2013 3:33 PM, "Johnny Bridges" <jhbridges@ymail.com> wrote:
> >If< folks will be reasonable (three or four on hand at the time) I don't
> mind healing them up for a freebie. That way, if it doesn't work, you've
> lost nothing but a bit of time. The relays might run to some money -
> twenty bux maybe - but beyond that the parts are basically nickel items. I
> have bench stock on most of them. The two three terminal diodes want some
> looking at. One is an SCR, fairly easy to source, and I expect the other
> is actually some flavor of transistor. Again, if it can be found or
> replaced with a newer component, not a great problem. I look on it as a
> 'pay it forward', people on this list have helped me out and saved me a
> modest fortuna over the last year and a half. So let's give this a try:
>
> 1. The GMCer in/near Orlando who asked about this last Fall gets first if
> he's still interested (lost all my emails in a change)
> 2. No charge, but also no guarantees. (If it doesn't work now, all you're
> out is time)
> 3. Send to me in the Small UPS Box, and pad it with something... crushed
> newsprint, bubble, whatever.
> 4. Whatever the Postal Orifice wants to send it, include that much in
> stamps so I can send it back. (The boxes are free, I got them)
> 5. >don't< disconnect the wires from the board, disconnect the Molex
> (square white connector) and send the 'pigtail' of wires with the board.
> 6. Be sure to include name and mailing address so you get it back.
> 7. BE REALISTIC! If the board looks like a charcoal briquette, call one
> of our suppliers and pop for a new or rebuilt.
>
> On that basis, if the gent in Orlando will reply here and send one or two
> of his to
>
> Johnny Bridges
> 4029 Tanner's Mill Road
> Braselton, GA 30517-1111
>
> I'll get started and we'll see how this works out. If he doesn't want to,
> how's to post and say so, and A gets next.
>
> --johnny
> '76 23' transmode norris
> '76 palm beach
> --------------------------------------------
> On Mon, 7/15/13, A. <markbb1@netzero.com> wrote:
>
> Subject: Re: [GMCnet] Onan Control Board Question
> To: gmclist@temp.gmcnet.org
> Date: Monday, July 15, 2013, 4:56 PM
>
>
>
>
> Johnny,
>
> It is always nice to have options. And Jim K is a good
> one for replacement boards. But how willing would you
> be to evaluate Onan boards for GMCers?
>
> What I am thinking is USPS postage for a small box is
> cheap. Someone could send you a board in a well
> packed/protected package for next to nothing. You
> could look at it and estimate cost to repair and advise the
> owner (with options, like slathering with conformal
> coating). If he agrees to the price, you fix the
> board, he sends you money (to include return shipping) and
> you send it back to the owner.
>
> Everyone needs to understand there is no warranty.
>
> If the owner doesn't want to pay that much, he can either
> tell you to keep/dispose of the board, or he can arrange to
> get it back in the condition you received it.
>
> What do you think? Is it likely that shipping both
> ways, plus repairs, would be cost effective?
> --
> '73 23' Sequoia For Camping
> '73 23' CanyonLands For Sale
> UA (Upper Alabama)
> "Time is money. If you use YOUR time, you get to keep
> YOUR money."
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Onan Control Board Question [message #214520 is a reply to message #214518] |
Mon, 15 July 2013 19:17 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Thanks, it'll save me a trip through my sub manuals. The board cover gives the ECG replacements for the relay that doesn't fail, I can source the other one but it may need mounting.
--johnny
--------------------------------------------
On Tue, 7/16/13, Ken Henderson <hend4800@bellsouth.net> wrote:
Subject: Re: [GMCnet] Onan Control Board Question
To: "gmclist" <gmclist@temp.gmcnet.org>
Date: Tuesday, July 16, 2013, 12:12 AM
Johnny,
I went through all that parts substitution exercise back in
2001. The last
page of the Onan manual at bdub.net is my redrawn schematic,
with all the
needed part numbers. It's labelled "4 kW", but only
because that's what I
had -- 6 kW is identical.
Ken H.
On Jul 15, 2013 3:33 PM, "Johnny Bridges" <jhbridges@ymail.com>
wrote:
> >If< folks will be reasonable (three or four on
hand at the time) I don't
> mind healing them up for a freebie. That way, if
it doesn't work, you've
> lost nothing but a bit of time. The relays
might run to some money -
> twenty bux maybe - but beyond that the parts are
basically nickel items. I
> have bench stock on most of them. The two three
terminal diodes want some
> looking at. One is an SCR, fairly easy to source,
and I expect the other
> is actually some flavor of transistor. Again, if
it can be found or
> replaced with a newer component, not a great
problem. I look on it as a
> 'pay it forward', people on this list have helped me
out and saved me a
> modest fortuna over the last year and a half. So
let's give this a try:
>
> 1. The GMCer in/near Orlando who asked about this last
Fall gets first if
> he's still interested (lost all my emails in a change)
> 2. No charge, but also no guarantees. (If it
doesn't work now, all you're
> out is time)
> 3. Send to me in the Small UPS Box, and pad it with
something... crushed
> newsprint, bubble, whatever.
> 4. Whatever the Postal Orifice wants to send it,
include that much in
> stamps so I can send it back. (The boxes are
free, I got them)
> 5. >don't< disconnect the wires from the board,
disconnect the Molex
> (square white connector) and send the 'pigtail' of
wires with the board.
> 6. Be sure to include name and mailing address so you
get it back.
> 7. BE REALISTIC! If the board looks like a
charcoal briquette, call one
> of our suppliers and pop for a new or rebuilt.
>
> On that basis, if the gent in Orlando will reply here
and send one or two
> of his to
>
> Johnny Bridges
> 4029 Tanner's Mill Road
> Braselton, GA 30517-1111
>
> I'll get started and we'll see how this works out. If
he doesn't want to,
> how's to post and say so, and A gets next.
>
> --johnny
> '76 23' transmode norris
> '76 palm beach
> --------------------------------------------
> On Mon, 7/15/13, A. <markbb1@netzero.com>
wrote:
>
> Subject: Re: [GMCnet] Onan Control Board
Question
> To: gmclist@temp.gmcnet.org
> Date: Monday, July 15, 2013, 4:56 PM
>
>
>
>
> Johnny,
>
> It is always nice to have options. And Jim
K is a good
> one for replacement boards. But how willing
would you
> be to evaluate Onan boards for GMCers?
>
> What I am thinking is USPS postage for a small
box is
> cheap. Someone could send you a board in a
well
> packed/protected package for next to
nothing. You
> could look at it and estimate cost to repair and
advise the
> owner (with options, like slathering with
conformal
> coating). If he agrees to the price, you
fix the
> board, he sends you money (to include return
shipping) and
> you send it back to the owner.
>
> Everyone needs to understand there is no
warranty.
>
> If the owner doesn't want to pay that much, he
can either
> tell you to keep/dispose of the board, or he can
arrange to
> get it back in the condition you received it.
>
> What do you think? Is it likely that
shipping both
> ways, plus repairs, would be cost effective?
> --
> '73 23' Sequoia For Camping
> '73 23' CanyonLands For Sale
> UA (Upper Alabama)
> "Time is money. If you use YOUR time, you
get to keep
> YOUR money."
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
GMCnet mailing list
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_______________________________________________
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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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| Re: [GMCnet] Onan Control Board Question [message #214534 is a reply to message #214512] |
Mon, 15 July 2013 20:22 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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I know when our customer tells us that they are having a problem with a
part, we send him a new freight prepaid.
If it is a heavy part like the shock or fan clutch, we will issue a call
tag so customer does not have to pay freight.
Should you not mention a problem, I feel that I cannot read your mind.
On Mon, Jul 15, 2013 at 4:36 PM, A. <markbb1@netzero.com> wrote:
>
>
> Johnny Bridges wrote on Mon, 15 July 2013 17:33
> > ...I'll get started and we'll see how this works out. If he doesn't want
> to, how's to post and say so, and A gets next.
> >
> > --johnny
> > '76 23' transmode norris
> > '76 palm beach
> Thanks for that. I don't know yet if/when I might need the service,
> 'cause I haven't even tried to fire mine up yet. Later this month, I
> hope...
> --
> '73 23' Sequoia For Camping
> '73 23' CanyonLands For Sale
> UA (Upper Alabama)
> "Time is money. If you use YOUR time, you get to keep YOUR money."
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Jim Kanomata
Applied/GMC, Fremont,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 Control Board Question [message #214541 is a reply to message #214518] |
Mon, 15 July 2013 21:08 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
|
Senior Member |
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Having worked on and "fixed" more of these than I care to talk about, I am suggesting that for anything more than minor problems that you just buy a new Dinosaur board. I would estimate the at least 50% of the boards I have "fixed" involved the K2 "up to speed" relay circuit. Since a direct replacement for K2 is not available and the relay coil usually opens up due to a failing CR1, C1, or R1, just replacing K2 with a substitute is not a long term fix. If the replacement K2 does not have the same coil resistance then the value of R1 needs to also be recalculated and changed.
Most of the capacitors on these boards have also aged out over the years and are in need of replacement. I have also found some resistors that have changed value over the years.
I would say 1/2 of the boards that I have "fixed" show up with a different problem in the next year or two.
So unless you want to experience off and on problems in the future, I suggest replacement of the board rather than repair. I have had a lot of them with cracked foil patterns around the pins and also blown patterns that required soldering patches or soldering jumpers around destroyed paths.
So yes you can "fix" them but I still question their longevity when you are finished.
I congratulate Johnny for offering to repair them. I just question the sanity (not his) of doing so.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Onan Control Board Question [message #214544 is a reply to message #214541] |
Mon, 15 July 2013 21:18 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I have a suggestion for you if you are replacing K2.
The relay is driven by 28 to 30 VAC from the built in alternator.
The AC is run through a single diode to make it 1/2 wave DC. Then the pulsing DC is dropped to 12 volts through a series resistor R1 and filtered a little by C1.
If you were to find a direct solder in replacement for K2 with a 24 to 30 VAC coil, then all of the additional components (R1, C1, and CR1) around K2 could be eliminated. Hopefully this would be a more reliable circuit.
I have often thought of trying to find such a relay but I never went through the effort.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Onan Control Board Question [message #214572 is a reply to message #214541] |
Tue, 16 July 2013 07:07 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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My sanity departed years ago, which is why I work in broadcast. Only place in the whirled where they will pay you yo have fun and not grow up.
I have had very few problems with these machines in remote service over the years. I suspect - but cannot prove - that buttoning them up in the 'power drawer' leads to a lot of the problems they present. They're derated due to both different manifolding and the fact that they run just hotter than all the proverbial things in RV service in that mount. Likewise, I feel like they vibrate more as well, due to the mounts and the different parts. Of course, vibration and heat are the enemies of curcuit boards and components. Given a few decades of shakin' and bakin' and they're going to have problems. They aren't unsurmountable problems until the board is completely cooked however. At that point, as Kanomata points out, you can have one quick quick with warranty for not an inordinate amount of money.
As an aside, my Onan guy (Cummins-Onan South) told me when the belt drive twins first came out, their merchant vendor was trying to develop a power drawer type RV setup for them but was having serious problems keeping them cool. I don't know if they ever succeeded, perhaps someone else does?
--johnny
'76 23' transmode norris
'76 palm beach
--------------------------------------------
On Tue, 7/16/13, Ken Burton <n9cv@comcast.net> wrote:
Subject: Re: [GMCnet] Onan Control Board Question
To: gmclist@temp.gmcnet.org
Date: Tuesday, July 16, 2013, 2:08 AM
Having worked on and "fixed" more of these than I care to
talk about, I am suggesting that for anything more than
minor problems that you just buy a new Dinosaur board.
I would estimate the at least 50% of the boards I have
"fixed" involved the K2 "up to speed" relay
circuit. Since a direct replacement for K2
is not available and the relay coil usually opens up due to
a failing CR1, C1, or R1, just replacing K2 with a
substitute is not a long term fix. If the replacement
K2 does not have the same coil resistance then the value of
R1 needs to also be recalculated and
changed.
Most of the capacitors on these boards have also aged out
over the years and are in need of replacement. I have
also found some resistors that have changed value over the
years.
I would say 1/2 of the boards that I have "fixed" show up
with a different problem in the next year or two.
So unless you want to experience off and on problems in the
future, I suggest replacement of the board rather than
repair. I have had a lot of them with cracked foil
patterns around the pins and also blown patterns that
required soldering patches or soldering jumpers around
destroyed paths.
So yes you can "fix" them but I still question their
longevity when you are finished.
I congratulate Johnny for offering to repair them. I
just question the sanity (not his) of doing so.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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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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