Home » Public Forums » GMCnet » Onan - No AC Outpus
| Re: Onan - No AC Outpus [message #245941 is a reply to message #245930] |
Mon, 31 March 2014 19:49   |
A Hamilto
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| A Hamilto wrote on Mon, 31 March 2014 19:21 |
| Steve Adams wrote on Mon, 31 March 2014 19:08 |
Ok, here is where I stand:
Emery, I measured the voltage at the circuit breaker. I am showing about 2.3 volts, not the 110-120 I was looking for.
I found two markings on the Bridge Rectifier + and -. They were very faint and difficult to read but they are there and I am now confident that I have it connected correctly as I was very careful to identify and mark each wire when removing the old BR.
I don't know that my spare BR is good, or if I may have done any damage by wiring it incorrectly the first time. At this point I am inclined to order a new BR and be careful to install it correctly. I will also read as much as I can about the generator end of the Onan.
Is there anything else I should be considering?
I think I read something somewhere about flashing the fields?
Any insight would be appreciated.
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IIRC, it has been posted here that installing the BR wrong will not damage it, but you won't get any AC out of the genset.
Have you checked both of your bridge rectifiers? You might have two good ones, or two bad ones, or one good and one bad.
To check the BR, set your multimeter for ohms, 20 or 200.
Hold the red probe on the minus pin. Check the resistance to each of the adjacent pins (apply the black probe to each in turn). Should be low to each.
Hold the red probe on the plus pin. Check the resistance to each of the adjacent pins (apply the black probe to each in turn). Should be high (out of range) to each.
If those tests check out the BR is ok and a new one won't do you any good.
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Being in a hurry, I only listed half the test procedure.
Other half is
Hold the black probe on the minus pin. Check the resistance to each of the adjacent pins (apply the red probe to each in turn). Should be high (out of range) to each.
Hold the black probe on the plus pin. Check the resistance to each of the adjacent pins (apply the red probe to each in turn). Should be low to each.
The MM says "low" is 8 ohms or less.
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| Re: [GMCnet] Onan - No AC Outpus [message #245944 is a reply to message #245929] |
Mon, 31 March 2014 20:27 |
Steve
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Location: East Greenville, Pa
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Take a multimeter, set it on Rx1 scale and touch the probes together. You should read 0.0 or something very close to zero. Then remove the BR and insert the probes into the + and - terminals. You should read around 38 ohms. Let us know what you find.
--Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
Jim, I set my multi-meter to measure Resistance or Ohms. When I touch the leads together it reads 0 L. I get the same 0 L reading when I touch the + and - terminals on BR #1. I will not be able to test BR #2 tonight.
I only have one Ohm setting and the meter auto ranges between M and K Ohms, I assume Mila and Kilo Ohms.
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1978 GMC Royal
Eastern Pennslyvania
1968 Chevrolet C20 396 Camper Special
1969 Chevrolet C20 Camper Special
1985 Buick Electra Park Avenue
1992 Camaro 25th Anniversary Heretage Edition Black
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| Re: [GMCnet] Onan - No AC Outpus [message #245949 is a reply to message #245933] |
Mon, 31 March 2014 20:45 |
Steve
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[quote title=Mr ERFisher wrote on Mon, 31 March 2014 20:27]did you read here?
http://gmcmotorhome.info/generator.html#bridge
good luck
erf
Gene, Yes, that's where I started and began to think it may be the Bridge Rectifier. I have now been performing the various tests suggested by others and I am not showing any measurement of ohms or resistance from any combination of pins on the Old BR. The new one is installed in the Onan and I will try to test it tomorrow.
When I try to measure the Ohms of any wire, or touch the leads together I get various readings but absolutely nothing from the BR.
1978 GMC Royal
Eastern Pennslyvania
1968 Chevrolet C20 396 Camper Special
1969 Chevrolet C20 Camper Special
1985 Buick Electra Park Avenue
1992 Camaro 25th Anniversary Heretage Edition Black
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| Re: Onan - No AC Outpus [message #245954 is a reply to message #245927] |
Mon, 31 March 2014 20:53 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
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| Steve Adams wrote on Mon, 31 March 2014 19:08 |
Ok, here is where I stand:
Emery, I measured the voltage at the circuit breaker. I am showing about 2.3 volts, not the 110-120 I was looking for.
I found two markings on the Bridge Rectifier + and -. They were very faint and difficult to read but they are there and I am now confident that I have it connected correctly as I was very careful to identify and mark each wire when removing the old BR.
I don't know that my spare BR is good, or if I may have done any damage by wiring it incorrectly the first time. At this point I am inclined to order a new BR and be careful to install it correctly. I will also read as much as I can about the generator end of the Onan.
Is there anything else I should be considering?
I think I read something somewhere about flashing the fields?
Any insight would be appreciated.
|
Do you know how to use an ohm meter?
If you, do that bridge is just 4 diodes wired in a circle or square. Just measure between each set of adjacent pin in both directions. One way should read high resistance and the opposite polarity should read low resistance If you find one that is different than the other three then you have bad bridge rectifier.
http://www.youtube.com/watch?v=dqkT6hF0O3E
http://upload.wikimedia.org/wikipedia/commons/1/13/4_diodes_bridge_rectifier.jpg
http://en.wikipedia.org/wiki/Bridge_rectifier
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Onan - No AC Outpus [message #245957 is a reply to message #245944] |
Mon, 31 March 2014 20:52 |
Jim Miller
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Hi Steve,
First confirm that your meter is working and that you understand what it is saying. Set it on Rx1 if possible, or on the less desirable setting of "Auto". With the leads apart it should read OL (==overload/out-of-range) or equivalent. Then touch the leads together - the reading should drastically change and become something like 0.0 or 0.1. The former means "open circuit" and the latter means "short circuit". It is important to understand the distinction between the two with regard to how your meter reads out.
Instead of testing the BR itself, I want you to set the BR aside and insert the meter probes into the BR socket's + and - terminals. Red/Black doesn't matter. If you read 38 or thereabouts then that eliminates your generator's field winding as the source of the problem and you can then go onto other more complex troubleshooting. If, when you measure the + and - terminals in the BR's socket and you read OL or some other very large number on your meter then you likely have a field assembly problem and you can stop troubleshooting.
Only after you eliminate the field assembly as the problem should you continue with more complex procedures of testing the bridge. At this point in time the field assemblies are failing at a higher rate than the bridge rectifiers which is why I recommend spending 30 seconds to test the field first.
--Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
On Mar 31, 2014, at 9:28 PM, Steve Adams wrote:
>
>
>
> Take a multimeter, set it on Rx1 scale and touch the probes together. You should read 0.0 or something very close to zero. Then remove the BR and insert the probes into the + and - terminals. You should read around 38 ohms. Let us know what you find.
>
>
>
>
> Jim, I set my multi-meter to measure Resistance or Ohms. When I touch the leads together it reads 0 L. I get the same 0 L reading when I touch the + and - terminals on BR #1. I will not be able to test BR #2 tonight.
>
>
> I only have one Ohm setting and the meter auto ranges between M and K Ohms, I assume Mila and Kilo Ohms.
> _______________________________________________
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> [/quote]
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> --
> 1978 GMC Royal
> Eastern Pennslyvania
> 1968 Chevrolet C20 396 Camper Special
> 1969 Chevrolet C20 Camper Special
> 1985 Buick Electra Park Avenue
> 1992 Camaro 25th Anniversary Heretage Edition Black
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1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: [GMCnet] Onan - No AC Outpus [message #245962 is a reply to message #245954] |
Mon, 31 March 2014 21:06 |
Jim Miller
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Given how many fields have failed in the past few years.... why don't we let this fellow spend 30 seconds to test his field and eliminate it as the problem before trying to walk through a bridge test and any number of other speculative causes that require more complex troubleshooting procedures?
Seriously, when is the last time anyone saw a BR fail? Of all the GMCs and Onans that have been through my place since 2008 only ONE of them had a bad bridge - and that was my personal GMC when I first bought it; after replacing the bridge the field failed a year later. In search of a replacement I personally tested a whole PILE of dead Onans at a GMC Vendor's site and every single one of them had a bad field.
I suggest going after low-hanging-fruit first and that is a field test in this case.
--Jim
On Mar 31, 2014, at 9:53 PM, Ken Burton wrote:
>
>
> Steve Adams wrote on Mon, 31 March 2014 19:08
>> Ok, here is where I stand:
>>
>> Emery, I measured the voltage at the circuit breaker. I am showing about 2.3 volts, not the 110-120 I was looking for.
>>
>> I found two markings on the Bridge Rectifier + and -. They were very faint and difficult to read but they are there and I am now confident that I have it connected correctly as I was very careful to identify and mark each wire when removing the old BR.
>>
>> I don't know that my spare BR is good, or if I may have done any damage by wiring it incorrectly the first time. At this point I am inclined to order a new BR and be careful to install it correctly. I will also read as much as I can about the generator end of the Onan.
>>
>> Is there anything else I should be considering?
>>
>> I think I read something somewhere about flashing the fields?
>>
>> Any insight would be appreciated.
>
> Do you know how to use an ohm meter?
>
> If you, do that bridge is just 4 diodes wired in a circle or square. Just measure between each set of adjacent pin in both directions. One way should read high resistance and the opposite polarity should read low resistance If you find one that is different than the other three then you have bad bridge rectifier.
>
> http://www.youtube.com/watch?v=dqkT6hF0O3E
>
> http://upload.wikimedia.org/wikipedia/commons/1/13/4_diodes_bridge_rectifier.jpg
>
> http://en.wikipedia.org/wiki/Bridge_rectifier
>
>
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
> _______________________________________________
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--Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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Jim Miller
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1977 Royale
Hamilton, OH
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| Re: Onan - No AC Outpus [message #245966 is a reply to message #245891] |
Mon, 31 March 2014 21:33 |
Steve
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Location: East Greenville, Pa
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Thanks for all the input.
Jim, I will set the BR aside and test the field by measuring at the + and - of the socket and let you know. It may take a few days for me to get to it as I have a heavy work schedule over the next few days.
1978 GMC Royal
Eastern Pennslyvania
1968 Chevrolet C20 396 Camper Special
1969 Chevrolet C20 Camper Special
1985 Buick Electra Park Avenue
1992 Camaro 25th Anniversary Heretage Edition Black
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| Re: [GMCnet] Onan - No AC Outpus [message #245973 is a reply to message #245962] |
Mon, 31 March 2014 22:43 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
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That is not a bad idea Jim, but in this case he already pulled the bridge before posting here and as long as it is out, he should figure out if either the new or removed one is bad.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Onan - No AC Outpus [message #245986 is a reply to message #245954] |
Tue, 01 April 2014 03:46 |
mickeysss
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Registered: January 2012
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If you were stuck on an island with an onan the below would help?
>> http://www.gmcws.org/Tech/dsimmons/onan/onan.html
> http://www.bdub.net/manuals/onanmanual.pdf
http://gmcmotorhome.info/list.html#GEN
http://www.gmcmhphotos.com/photos/onan-video/p7015.html
order the dvd from the late and great duane simmons, go to :::
$12 contact:
tmaki@earthlink.net
On Mar 31, 2014, at 6:53 PM, Ken Burton wrote:
>
>
> Steve Adams wrote on Mon, 31 March 2014 19:08
>> Ok, here is where I stand:
>>
>> Emery, I measured the voltage at the circuit breaker. I am showing about 2.3 volts, not the 110-120 I was looking for.
>>
>> I found two markings on the Bridge Rectifier + and -. They were very faint and difficult to read but they are there and I am now confident that I have it connected correctly as I was very careful to identify and mark each wire when removing the old BR.
>>
>> I don't know that my spare BR is good, or if I may have done any damage by wiring it incorrectly the first time. At this point I am inclined to order a new BR and be careful to install it correctly. I will also read as much as I can about the generator end of the Onan.
>>
>> Is there anything else I should be considering?
>>
>> I think I read something somewhere about flashing the fields?
>>
>> Any insight would be appreciated.
>
> Do you know how to use an ohm meter?
>
> If you, do that bridge is just 4 diodes wired in a circle or square. Just measure between each set of adjacent pin in both directions. One way should read high resistance and the opposite polarity should read low resistance If you find one that is different than the other three then you have bad bridge rectifier.
>
> http://www.youtube.com/watch?v=dqkT6hF0O3E
>
> http://upload.wikimedia.org/wikipedia/commons/1/13/4_diodes_bridge_rectifier.jpg
>
> http://en.wikipedia.org/wiki/Bridge_rectifier
>
>
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] Onan - No AC Outpus [message #245992 is a reply to message #245939] |
Tue, 01 April 2014 06:26 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
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You're right, I was having a bad day, pay no attention to the fool with the box of the silly things on the wall five feet away.
THE CUT CORNER IS POSITIVE
--johnny
________________________________
From: Ken Henderson <hend4800@bellsouth.net>
To: gmclist <gmclist@temp.gmcnet.org>
Sent: Monday, March 31, 2014 8:43 PM
Subject: Re: [GMCnet] Onan - No AC Outpus
Johnny,
Read again what you wrote -- I'm sure you know better!
The uniquely marked corner, whether beveled, slanted, marked with a red
dot, an in- or out-dimple, or otherwise, is ALWAYS the positive (Cathode)
terminal of a bridge rectifier. The diagonally opposite terminal is the
negative. The other two are the ac terminals so it doesn't matter which
way their wires are connected.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL
www.gmcwipersetc.com
On Mon, Mar 31, 2014 at 3:33 PM, Johnny Bridges <jhbridges@ymail.com> wrote:
> The bridge should have one slanted corner. The connection on that corner
> and the one opposite should be the AC inputs. Your meter will tell you
> which of the other two is + and which -.
>
> --johnny
>
>
>
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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: Onan - No AC Output [message #246101 is a reply to message #245891] |
Tue, 01 April 2014 19:43 |
Steve
Messages: 506
Registered: September 2013
Location: East Greenville, Pa
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Ok, Quick Update. Some good news.
Ken Burton,
I thought I knew how to use a multi-meter but I was getting crazy readings from my fancy meter with auto range sensing. It was 2 volts from a 110 volt outlet. Obviously not working properly I tracked down my simple meter where you can manually select the range and the meter is working properly. Now that I have a good meter I will be able to perform the various tests suggested by forum members. Ken, many thanks for all of your posts on various topics.
Jim Miller,
You had me really worried about testing the generator field to check for 38 Ohms. I just got home from work and will not be able to test mine tonight. However, I also have a donor Onan thanks to another forum member, Sean Kid. Since it was in the shop with the wires easily accessible, I performed the test as you suggested and the donor Onan is reading exactly 38 Ohms. Knowing that will help me sleep better the rest of the week until I can get back at this on the weekend. I am still hoping my will be good as well but at least I know I have a backup, although I seem to recall reading that separating the gen from the engine can be a chore. Jim, many thanks to you as well.
If I don't have electricity and air conditioning I will never get Mrs. Adams to go along with me.
1978 GMC Royal
Eastern Pennslyvania
1968 Chevrolet C20 396 Camper Special
1969 Chevrolet C20 Camper Special
1985 Buick Electra Park Avenue
1992 Camaro 25th Anniversary Heretage Edition Black
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| Re: [GMCnet] Onan - No AC Output [message #246107 is a reply to message #246101] |
Tue, 01 April 2014 20:09 |
Jim Miller
Messages: 501
Registered: March 2008
Karma: 10
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On Apr 1, 2014, at 8:43 PM, Steve Adams wrote:
> Since it was in the shop with the wires easily accessible, I performed the test as you suggested and the donor Onan is reading exactly 38 Ohms.
It is great that you have a known good specimen to use as a confirmation of your test methodology. If only all Onan repairers were in the same situation!
> I am still hoping my will be good as well but at least I know I have a backup, although I seem to recall reading that separating the gen from the engine can be a chore. Jim, many thanks to you as well.
I hope yours will be good as well. There are several things to consider at this point:
1) You said it made AC a week ago. That means that the remanent magnetism in the field assembly will still be present and that you do not need to do a "re-flash".
2) It is unlikely your bridge rectifier has suffered a failure unless you ran the unit with a large electrical load (air conditioners and perhaps the hot water heater) and then shut it down abruptly while that load was still in place. Doing so causes the AC voltage across the bridge to soar and in some cases cooks one or more diodes in the bridge. Don't worry about this yet.
3) You said you had 2-3 VAC coming out of the unit. This is a classic indicator of no excitation from the field windings. There is enough magnetism remaining in the field assembly to produce this amount of potential on its own.
4) If you had the + and - wires reversed you would have 0 VAC output instead of 2 VAC. This is because the remanent magnetism mentioned earlier will start to produce voltage which, due to the reversed + and - wires, will immediately excite the field in the opposite polarity thus cancelling itself. Remember the rule of generation: rotating a coil through a magnetic field produces electricity in that coil. Remove the rotation or remove the magnetic field - and you have no electricity. 2 VAC is NOT "no-electricity".
Separating the field from the engine is not a big deal - remove four tie-bolts and unbolt some accessories (fuel pump and control board) and then do some GENTLE prying and the rear bell housing will come right off followed by the field. The chore you may have heard about is removing the armature - the rotating part - from the engine crankshaft. That is indeed a PITA that should not be attempted unless absolutely necessary.
The only other situation that I can think of that would cause your problem is if the stranded wire that goes from the bridge to the field windings have become separated at the spade lug junction between them. This is unlikely to occur and in working on Onans for the past 6 years I have never seen it happen.
If you are really interested in the construction of the field assembly then take a look at my web page http://www.jcmco.com/gallery/onanfieldassyrepair - this shows the process that my father and I have developed to repair dead fields.
--Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: [GMCnet] Onan - No AC Output [message #246108 is a reply to message #246101] |
Tue, 01 April 2014 20:14 |
Jim Miller
Messages: 501
Registered: March 2008
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On Apr 1, 2014, at 8:43 PM, Steve Adams wrote:
> I thought I knew how to use a multi-meter but I was getting crazy readings from my fancy meter with auto range sensing. It was 2 volts from a 110 volt outlet.
I think you may have had it on the DC VOLTS scale in that circumstance in which case 2 volts (essentially a nuisance reading) would be believable. It is always a good idea to test your instrumentation against known sources before using it against unknowns.
> Obviously not working properly I tracked down my simple meter where you can manually select the range and the meter is working properly.
Autoranging meters have their place in this world but your simple meter- whatever model it might have been - can be a much more useful tool in some cases.
--Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: Onan - No AC Outpus [message #246452 is a reply to message #245891] |
Sat, 05 April 2014 10:40 |
Steve
Messages: 506
Registered: September 2013
Location: East Greenville, Pa
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Bridge Rectifier (BR) testing results:
I now have a multimeter that is functioning correctly and following various instructions from helpers on the GMC net, including the u-tube video link from Gene, I have been able to perform the following tests:
BR number 1 - appears to be bad. I get no readings across any of the appropriate pins. High resistance Over Load or Outside Limit, no Low readings
BR number 2 - appears to be bad. I get no readings across any of the appropriate pins High resistance Overload or Outside Limit, no Low readings
I believe the meter is working correctly because when the leads are apart I get outside limit and when I touch them together I get near zero. I am also able to measure resistance of wires and speakers.
I have also done an initial test of the field assembly as suggested by Jim Miller by testing across the + and - terminals in the BR socket. I am getting a reading of 38 ohms across those terminals. Jim Miller also provided a link to his web site with repair photos where he rebuilds the generator end, complete with new windings on a metal lathe. Very interesting and cool. I would highly recommend it.
My initial conclusions are that I have bad BR's and will likely order a new one. Jim seemed to indicate that there were additional testing that I could do. Additional help would be greatly appreciated.
1978 GMC Royal
Eastern Pennslyvania
1968 Chevrolet C20 396 Camper Special
1969 Chevrolet C20 Camper Special
1985 Buick Electra Park Avenue
1992 Camaro 25th Anniversary Heretage Edition Black
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| Re: [GMCnet] Onan - No AC Outpus [message #246453 is a reply to message #246452] |
Sat, 05 April 2014 10:51 |
k2gkk
Messages: 4452
Registered: November 2009
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Did you also reverse the leads on every test you did on the bridge rectifier, Steve? Each diode is supposed to conduct in just one direction.
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~~ k2gkk @ hotmail dot com ~~
~ ~ USAF and FAA, Retired ~ ~
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> To: gmclist@temp.gmcnet.org
> From: sjadams@ptd.net
> Date: Sat, 5 Apr 2014 10:40:35 -0500
> Subject: Re: [GMCnet] Onan - No AC Outpus
>
>
>
> Bridge Rectifier (BR) testing results:
>
> I now have a multimeter that is functioning correctly and following various instructions from helpers on the GMC net, including the u-tube video link from Gene, I have been able to perform the following tests:
>
> BR number 1 - appears to be bad. I get no readings across any of the appropriate pins. High resistance Over Load or Outside Limit, no Low readings
>
> BR number 2 - appears to be bad. I get no readings across any of the appropriate pins High resistance Overload or Outside Limit, no Low readings
>
> I believe the meter is working correctly because when the leads are apart I get outside limit and when I touch them together I get near zero. I am also able to measure resistance of wires and speakers.
>
> I have also done an initial test of the field assembly as suggested by Jim Miller by testing across the + and - terminals in the BR socket. I am getting a reading of 38 ohms across those terminals. Jim Miller also provided a link to his web site with repair photos where he rebuilds the generator end, complete with new windings on a metal lathe. Very interesting and cool. I would highly recommend it.
>
> My initial conclusions are that I have bad BR's and will likely order a new one. Jim seemed to indicate that there were additional testing that I could do. Additional help would be greatly appreciated.
>
> --
> 1978 GMC Royal
> Eastern Pennslyvania
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| Re: Onan - No AC Outpus [message #246456 is a reply to message #245891] |
Sat, 05 April 2014 11:27 |
Steve
Messages: 506
Registered: September 2013
Location: East Greenville, Pa
Karma: 1
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Senior Member |
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Bob,
I did reverse the leads for each part of the test. I picked that up from the U Tube video. That's where I do get an interesting result. When testing with the red lead on the - pin I do get just a quick flash on the meter of a random number before it quickly goes to Over Load or Outside Limit. I was viewing that as still failing. I would think a good diod would give you a steady reading, not just a flash of a random number?
1978 GMC Royal
Eastern Pennslyvania
1968 Chevrolet C20 396 Camper Special
1969 Chevrolet C20 Camper Special
1985 Buick Electra Park Avenue
1992 Camaro 25th Anniversary Heretage Edition Black
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| Re: [GMCnet] Onan - No AC Outpus [message #246457 is a reply to message #246452] |
Sat, 05 April 2014 11:33 |
Dave Mumert
Messages: 272
Registered: February 2004
Location: Olds, AB, Canada
Karma: 0
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Senior Member |
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Hi Steve
Some meters use a low voltage for resistance measurements, low enough so as to not cause diodes to conduct. That is so you can
measure resistance in circuit without getting errors caused by diodes, or transistors in the circuit.
Does your meter have a diode function?
Dave Mumert
'76 Eleganza II
Alberta, CA
> -----Original Message-----
> Subject: Re: [GMCnet] Onan - No AC Outpus
>
> Bridge Rectifier (BR) testing results:
>
> I now have a multimeter that is functioning correctly and following various instructions from helpers on the GMC net, including
the u-
> tube video link from Gene, I have been able to perform the following tests:
>
> BR number 1 - appears to be bad. I get no readings across any of the appropriate pins. High resistance Over Load or Outside
Limit, no
> Low readings
>
> BR number 2 - appears to be bad. I get no readings across any of the appropriate pins High resistance Overload or Outside Limit,
no
> Low readings
>
> I believe the meter is working correctly because when the leads are apart I get outside limit and when I touch them together I get
> near zero. I am also able to measure resistance of wires and speakers.
>
> I have also done an initial test of the field assembly as suggested by Jim Miller by testing across the + and - terminals in the
BR socket. I
> am getting a reading of 38 ohms across those terminals. Jim Miller also provided a link to his web site with repair photos where
he
> rebuilds the generator end, complete with new windings on a metal lathe. Very interesting and cool. I would highly recommend it.
>
> My initial conclusions are that I have bad BR's and will likely order a new one. Jim seemed to indicate that there were
additional
> testing that I could do. Additional help would be greatly appreciated.
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| Re: [GMCnet] Onan - No AC Outpus [message #246460 is a reply to message #246457] |
Sat, 05 April 2014 11:49 |
Steve
Messages: 506
Registered: September 2013
Location: East Greenville, Pa
Karma: 1
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Senior Member |
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| Dave Mumert wrote on Sat, 05 April 2014 12:33 |
Hi Steve
Some meters use a low voltage for resistance measurements, low enough so as to not cause diodes to conduct. That is so you can
measure resistance in circuit without getting errors caused by diodes, or transistors in the circuit.
Does your meter have a diode function?
|
Dave, I don't know that it does. It is a pretty simple unit. I have a nicer one with more functions including auto ranging but it is not working properly (either that or I am not smart enough to figure it out).
1978 GMC Royal
Eastern Pennslyvania
1968 Chevrolet C20 396 Camper Special
1969 Chevrolet C20 Camper Special
1985 Buick Electra Park Avenue
1992 Camaro 25th Anniversary Heretage Edition Black
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