Home » Public Forums » GMCnet » Inherited a GMC! Hello and please help me!!! (help needed.)
| Inherited a GMC! Hello and please help me!!! [message #308628] |
Wed, 12 October 2016 13:13  |
Atom Ant
Messages: 170
Registered: October 2016
Location: Austin, TX
Karma: 0
|
Senior Member |
|
|
Hello everyone!--
My wife and I just inherited the use of a 1976 GMC Palm Beach from her father. I'll be working on and restoring it in return for use.
The PO has some VERY creative wiring going on in this thing, and I'm no electrician. (I'm sure non of you have ever heard this story before...)
I am hoping to pick the collective brain trust here, and restore this back to it's former beauty with your help.
My very first question is:
why would someone bypass the isolator? there are no wires running to it in this coach.
there are 5 (yes, 5) batteries in this coach. Two at the Onan, one next to the converter, one in the outside compartment near the door, and the chassis battery.
I cannot tell you which one the charger is charging.
any ideas?
1976 Palm Beach
Austin, TX
|
|
|
|
| Re: [GMCnet] Inherited a GMC! Hello and please help me!!! [message #308629 is a reply to message #308628] |
Wed, 12 October 2016 13:35  |
Steve Jess
Messages: 169
Registered: April 2012
Karma: 0
|
Senior Member |
|
|
> why would someone bypass the isolator?
It might have gone bad. If you have a voltmeter you should be able to test it. It's basically two diodes.
> I cannot tell you which one the charger is charging.
Here's another place a voltmeter comes in handy. With shore power connected, check the voltage at each battery. The ones that read 14 V (plus or minus) are getting charged.
The batteries could all be connected in parallel, which is not a good thing and can even be dangerous.
If you don't have a voltmeter, a trip to Harbor Freight is in order. They often have them for little or no cost with a coupon.
Steve Jess - Tucson, AZ
Mid-day/PM newscaster
Arizona Public Media
________________________________
From: Gmclist on behalf of Adam Metzger
Sent: Wednesday, October 12, 2016 11:13 AM
To: gmclist@list.gmcnet.org
Subject: [GMCnet] Inherited a GMC! Hello and please help me!!!
Hello everyone!--
My wife and I just inherited the use of a 1976 GMC Palm Beach from her father. I'll be working on and restoring it in return for use.
The PO has some VERY creative wiring going on in this thing, and I'm no electrician. (I'm sure non of you have ever heard this story before...)
:p
I am hoping to pick the collective brain trust here, and restore this back to it's former beauty with your help.
My very first question is:
why would someone bypass the isolator? there are no wires running to it in this coach.
there are 5 (yes, 5) batteries in this coach. Two at the Onan, one next to the converter, one in the outside compartment near the door, and the
chassis battery.
I cannot tell you which one the charger is charging.
any ideas?
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Gmclist Info Page - list.gmcnet.org
list.gmcnet.org
To see the collection of prior postings to the list, visit the Gmclist Archives. Using Gmclist: To post a message to all the list members, send email ...
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
| Re: Inherited a GMC! Hello and please help me!!! [message #308630 is a reply to message #308628] |
Wed, 12 October 2016 13:46 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
|
Senior Member |
|
|
Time to learn! get a VOM meter:
http://www.harborfreight.com/7-function-digital-multimeter-90899.html
set it to volts and connect the leads of the meter to the battery + and -
plug in and disconnect the coach, when voltage is 13.1 volts or less, then it is not charging. when coach is plugged in, and it reads more then 13.1 volts(normally 13.9 or 14), then that battery is being charged with then coach is plugged in.
Anyway- normally there would be 1 battery up front(starts and runs engine), and 1 battery in rear by generator(runs lights, fridge, ect). the converter only charges that rear battery, the isolator charges both batteries from the alternator when the engine is running. would only be bypassed if it quit working, or they installed what is called a "combiner"
fun times ahead.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
|
|
|
|
| Re: [GMCnet] Inherited a GMC! Hello and please help me!!! [message #308631 is a reply to message #308629] |
Wed, 12 October 2016 13:54 |
Atom Ant
Messages: 170
Registered: October 2016
Location: Austin, TX
Karma: 0
|
Senior Member |
|
|
of course. seems simple enough. Again, there is some creative wiring going on here. There is a Stanley charger in the coach, plugged into the AC, with the two charging clamps attached to two wires. the wires run down to a big mess of wire ends at the converter box, to which there are also connected two wires running to a battery.
I'll get my multimeter out and start poking around.
I'm sure I can search it, but how does one test a isolator?
I want to thank eveyone in advance for what will surely be thousands of questions. I'm not afraid of mechanical work, and have dome some significant repairs on cars before, but electrical is something I have a very healthy admiration for. From afar.
1976 Palm Beach
Austin, TX
|
|
|
|
| Re: [GMCnet] Inherited a GMC! Hello and please help me!!! [message #308634 is a reply to message #308631] |
Wed, 12 October 2016 14:15 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
|
Senior Member |
|
|
you test the isolator in a similar fashion as the other "charge testing".
start testing isolator with engine off and coach unplugged from 110v A/C power, check voltages at each of the three posts on the isolator. Then fire up engine.
The wire from the alternator will have a higher voltage, and should go to the center post. the other two posts would go to each different battery bank(usually jumps over to the "boost solenoid"), and should be equal abotu 14 volts off each post.
if you have 14+ volts on center post, but only the same voltage on either of the outer posts as when you tested with engine off, the isolator is bad. If you have 14+ volts at each outside post, the islolator is probably OK.
It sounds like he is using a standard battery charger as his "converter" / charger. That is normally located in that cabnet just to the rear of the stove. OEM is a "buzzbox", big heavy metal charger. It is supposed to be hooked up to the frame in the back of the cabinet, and the positive hooks up to the fuse block. There is a wire from the fuse block that goes to a junction against the back wall in that cabnet, where one wire runs rear to the battery compartment by the generator, and the other runs all the way up to the front passenger side, and hooks to the "boost solenoid" the "boost solenoid" is engergized by the "boost" botton on the dash and basically ties the front and rear batteries together when needed.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
[Updated on: Wed, 12 October 2016 14:15] Report message to a moderator |
|
|
|
| Re: [GMCnet] Inherited a GMC! Hello and please help me!!! [message #308635 is a reply to message #308631] |
Wed, 12 October 2016 14:29 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
|
Senior Member |
|
|
Isolator is easy to test. For the test, the isolator does not have to be wired to anything. Just connect one lead from millimeter to center post and other lead to each outer post. No reading indicates an open diode. Open diode equals dead isolator leg. Diodes are polarity devices, so switch the leads for a double check. Or, just use the diode checking position on the multi-meter. Path is from central post to both outer posts. Center post is Engine alternator, with the outer posts going to each battery.
No connection at all to isolator? Where did the lead from the alternator get attached? How are the 5 batteries being charged? Sounds like the Stanley battery charger is charging your system. Is the converter that is in place the original blue "buzz box?" If so, plan on replacing it with a modern converter ASAP. Buzz box destroys batteries. I wonder what the connection at your boost switch looks like.
New 2 post isolator costs about $80, new converter about $140
You can get a large printout of the GMC wiring diagram from Allen Henderson. It sure is easier to follow than using the MM's tiny diagram.
Welcome to the cult, you are at the right place. There are no dumb questions. Most of us started at ground zero with our beloved GMC.
See you in Oklahoma, Spring 2017 GMC MI Rally.
Tom, MS II
2012 Phoenix Cruiser model 2552
KA4CSG
|
|
|
|
| Re: [GMCnet] Inherited a GMC! Hello and please help me!!! [message #308636 is a reply to message #308631] |
Wed, 12 October 2016 14:42 |
k2gkk
Messages: 4452
Registered: November 2009
Karma: -8
|
Senior Member |
|
|
Simply, the output of the alternator is applied to the center terminal. Voltage here (DC) should be around 14.3 to 14.8 Volts when engine is running. If isolator is okay, voltage at top and bottom terminals should be between .6 and .7 Volts lower than center terminal.
D C "Mac" Macdonald
OKC, OK
Sent from my iPad
> On Oct 12, 2016, at 13:55, Adam Metzger wrote:
>
> of course. seems simple enough. Again, there is some creative wiring going on here. There is a Stanley charger in the coach, plugged into the AC,
> with the two charging clamps attached to two wires. the wires run down to a big mess of wire ends at the converter box, to which there are also
> connected two wires running to a battery.
>
> I'll get my multimeter out and start poking around.
>
> I'm sure I can search it, but how does one test a isolator?
>
> I want to thank eveyone in advance for what will surely be thousands of questions. I'm not afraid of mechanical work, and have dome some significant
> repairs on cars before, but electrical is something I have a very healthy admiration for. From afar.
>
>
>
> _______________________________________________
> 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
|
|
|
|
| Re: Inherited a GMC! Hello and please help me!!! [message #308639 is a reply to message #308628] |
Wed, 12 October 2016 16:17 |
 |
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
|
Senior Member |
|
|
Adam,
Welcome to the group, family, cult, asylum...
First and most important. If you do not have all the manuals and documentation, go to Bdub's <http://www.bdub.net/GMCLinks.html> and collect them. NOW!!
Other than the documentation, while there collect a Black's (aka GMC Assist) list. There is probably someone close by that can be a whole lot of help.
Another important thing. As soon as practical, build a sigfile that has your name (so others will know it is you when they meet you), a short bit about the coach (there are differences between years and models that can matter), and a geographic reference. This forum is actually a mirror of a mailing list, and those that work the mail list don't get to see the header that starts each message on the forum. To set this up, go to Control Panel/Account Settings and scroll down. When you are done, you have to scroll down more and click "update".
Start planning now to be at the International at Shawnee the last week of March next year. Even if you can't bring the coach, get there. Austin to Shawnee is about 400 miles. It could be the best drive until you get to do all the others.
I kind of hate to ask, (you did say "inherited) but is father in law available to be queried?
The battery arrangement sounds really strange and if you can't get answers, it might be good to disconnect some before it gives you grief. The engineering that went into these coaches was sound, but there have been some technological advances. If you put it back together the way it left Pontiac 40 years ago, it will work. As I keep trying to tell new owners, get it safe to drive and reliable and enjoy it. Then, the work it requires will just be part of the Fun of owning a classic. Do you have a grease gun? Get one if you do not. If want a recommendation, I have one, but it isn't the cheapest. I will recommend that you find Valvoline Synpower grease.
Now, you found your way here and that is good. This is where you will find the people that know the facts. If you read any of the face book GMC sites, you will get a lot of information. Not all of it is valid and some has been dangerous. This is not to say you should not read the FB sites, just check what is there. About here. This is a community that may surprise you. When you get to know what is going on, you will find that the coach is not just another toy. It connects ts you with a community. This is a collection of people that are as helpful and supportive as you will find anywhere. There are stories that run about assistance and rescues that many find unbelievable. They are true. The only other community like this that I know of is that of the watermen that are my world. For that reason, I have taken to welcoming new owners that show up here much as any new owner or vessel would be welcomed there. So,
May the Good Lord bless this coach and all those that set forth within her.
Welcome Andy and family.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
|
|
|
|
| Re: Inherited a GMC! Hello and please help me!!! [message #308648 is a reply to message #308628] |
Wed, 12 October 2016 19:41 |
PigPen4x4
Messages: 61
Registered: March 2014
Location: Chattanooga Tn
Karma: 1
|
Member |
|
|
You've gotten some good advice here,
I'm going to add my 2 cents worth.
1. Remove what shouldn't be there.
It probably is not set up with good
circuit protection and as stated above
is probably not safe.
Remove the extra batteries and wires/cables.
2. The isolater was/is a mysterious device
to many.
All it does is direct current from the alternator
to the front and rear batteries without letting
each draw from the other. Clear as mud?
To test, place your meter in the ohms
or better yet continuity range.
Red lead to center, black to the each
of the other two.
Note the results
Now reverse them, black to center.
Note the results.
You should have continuity in one direction only.
Now the two outside terms, and reverse.
You should not show continuity at all.
They work fine, but again as above there
are better options available if bad.
You may need someone who understands
12 volt electrical systems.
A residential or commercial electrician
may not understand DC 12 volts.
They ain't the same.
Christopher Brewer
Chattanooga Tn
Well, no longer an owner.
|
|
|
|
| Re: [GMCnet] Inherited a GMC! Hello and please help me!!! [message #308651 is a reply to message #308628] |
Wed, 12 October 2016 20:00 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
Adam,
Welcome aboard!
Your electrical arrangement certainly sounds unique -- and dangerous.
Before you do anything else, download the wiring diagrams from:
http://www.bdub.net/wirediagrams/
You may even want to order the large version offered by my son, as at:
http://www.bdub.net/GMC_Motorhome_Wiring_Diagrams.pdf
WIth the chassis diagram at hand, look at the top where there two batteries
shown -- "12 V BAT AUXILIARY" and "12 V BAT". Those will henceforth be
known as the "House" and "Chassis" batteries, respectively.
The "LIVING AREA BATTERY PICKUP JUNCTION BLOCK" (LAJB) is probably located
about 2/3 of the way down the left side of the coach about 18" above the
floor on the outer wall of the coach. Most of the rest of the items shown
near the top of the page should be at the front of the coach, on the right
firewall or in the engine compartment. You should compare the diagram with
what you see there, perhaps using a highlighter to show on the diagram what
you understand as you proceed.
Once you've identified the source for chassis power ("80 AMP GENERATOR"
(generally known as "Alternator")), you may want to add a box to the left
of the aforementioned LAJB, with a line between the two; mark it
"Converter". That's not shown on the chassis diagram because it's provided
by the upfitter who added the "House" circuits.
You now have before you all the important information about your battery
system -- all the rest of the wires in the coach are "accessories" and of
no concern until you undertand this and have it working correctly. If
something is not connected as shown, disconnect it until you understand its
purpose and other connections.
When you feel comfortable with that "Standard" system, come back with more
questions.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, etc., etc., etc.
www.gmcwipersetc.com
On Wed, Oct 12, 2016 at 2:13 PM, Adam Metzger wrote:
> Hello everyone!--
>
> My wife and I just inherited the use of a 1976 GMC Palm Beach from her
> father. I'll be working on and restoring it in return for use.
>
> The PO has some VERY creative wiring going on in this thing, and I'm no
> electrician. (I'm sure non of you have ever heard this story before...)
>
> :p
>
> I am hoping to pick the collective brain trust here, and restore this back
> to it's former beauty with your help.
>
> My very first question is:
>
> why would someone bypass the isolator? there are no wires running to it
> in this coach.
>
> there are 5 (yes, 5) batteries in this coach. Two at the Onan, one next
> to the converter, one in the outside compartment near the door, and the
> chassis battery.
>
> I cannot tell you which one the charger is charging.
>
> any ideas?
>
> _______________________________________________
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
| Re: [GMCnet] Inherited a GMC! Hello and please help me!!! [message #308656 is a reply to message #308651] |
Wed, 12 October 2016 21:14 |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
|
Senior Member |
|
|
Adam,
Do you have an APC (alternator protection circuit) hooked up to the
alternator?
If not get one from Applied GMC or Gene Fisher.
On Wed, Oct 12, 2016 at 7:00 PM, Ken Henderson
wrote:
> Adam,
>
> Welcome aboard!
>
> Your electrical arrangement certainly sounds unique -- and dangerous.
> Before you do anything else, download the wiring diagrams from:
> http://www.bdub.net/wirediagrams/
>
> You may even want to order the large version offered by my son, as at:
> http://www.bdub.net/GMC_Motorhome_Wiring_Diagrams.pdf
>
> WIth the chassis diagram at hand, look at the top where there two batteries
> shown -- "12 V BAT AUXILIARY" and "12 V BAT". Those will henceforth be
> known as the "House" and "Chassis" batteries, respectively.
>
> The "LIVING AREA BATTERY PICKUP JUNCTION BLOCK" (LAJB) is probably located
> about 2/3 of the way down the left side of the coach about 18" above the
> floor on the outer wall of the coach. Most of the rest of the items shown
> near the top of the page should be at the front of the coach, on the right
> firewall or in the engine compartment. You should compare the diagram with
> what you see there, perhaps using a highlighter to show on the diagram what
> you understand as you proceed.
>
> Once you've identified the source for chassis power ("80 AMP GENERATOR"
> (generally known as "Alternator")), you may want to add a box to the left
> of the aforementioned LAJB, with a line between the two; mark it
> "Converter". That's not shown on the chassis diagram because it's provided
> by the upfitter who added the "House" circuits.
>
> You now have before you all the important information about your battery
> system -- all the rest of the wires in the coach are "accessories" and of
> no concern until you undertand this and have it working correctly. If
> something is not connected as shown, disconnect it until you understand its
> purpose and other connections.
>
> When you feel comfortable with that "Standard" system, come back with more
> questions.
>
> Ken H.
> Americus, GA
> '76 X-Birchaven w/Cad500/Howell EFI & EBL,
> Manny Brakes & 1-Ton, etc., etc., etc.
> www.gmcwipersetc.com
>
> On Wed, Oct 12, 2016 at 2:13 PM, Adam Metzger
> wrote:
>
>> Hello everyone!--
>>
>> My wife and I just inherited the use of a 1976 GMC Palm Beach from her
>> father. I'll be working on and restoring it in return for use.
>>
>> The PO has some VERY creative wiring going on in this thing, and I'm no
>> electrician. (I'm sure non of you have ever heard this story before...)
>>
>> :p
>>
>> I am hoping to pick the collective brain trust here, and restore this
> back
>> to it's former beauty with your help.
>>
>> My very first question is:
>>
>> why would someone bypass the isolator? there are no wires running to it
>> in this coach.
>>
>> there are 5 (yes, 5) batteries in this coach. Two at the Onan, one next
>> to the converter, one in the outside compartment near the door, and the
>> chassis battery.
>>
>> I cannot tell you which one the charger is charging.
>>
>> any ideas?
>>
>> _______________________________________________
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Bruce Hart
1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
|
|
|
|
| Re: Inherited a GMC! Hello and please help me!!! [message #308661 is a reply to message #308628] |
Wed, 12 October 2016 23:10 |
Atom Ant
Messages: 170
Registered: October 2016
Location: Austin, TX
Karma: 0
|
Senior Member |
|
|
Wow! I think I'm gonna like it here. Thanks for all the info and the warm welcome, everyone.
A bit of history-
This beautiful beast was owned by my wife's uncle. He recently passed away, and passed the coach to her father, who recruited us to "restore it" and enjoy it.
It's it good shape, everything works to some degree, and the PO knew his way around an engine, (he worked on the engine of his own airplane) but was not above "rigging", apparently.
I'll take some pics of the way things are wired, as I enjoy reverse engineering. (I've been known to go to the junk yard to take something a part, just to understand how it works).
1976 Palm Beach
Austin, TX
|
|
|
|
|
|
|
|
|
|
|
|
| Re: [GMCnet] Inherited a GMC! Hello and please help me!!! [message #308675 is a reply to message #308673] |
Thu, 13 October 2016 10:05 |
k2gkk
Messages: 4452
Registered: November 2009
Karma: -8
|
Senior Member |
|
|
My guess is that writer is measuring between center post and outside posts.
Auto-ranging digital multimeter is showing 540 and 545 millivolts which is GOOD (showing the voltage drop across the diodes)!
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ Since 30 November '53 ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ Member GMCMI and Classics ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ~ TZE166V101966 ~ ~ ~ ~
~ ~ ~ '76 ex-Palm Beach ~ ~ ~
~~ k2gkk + hotmail dot com ~~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
______________
|[ ]~~~[][ ][]\
"--OO--[]---O-"
________________________________
From: Gmclist on behalf of James Hupy
Sent: Thursday, October 13, 2016 09:53
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Inherited a GMC! Hello and please help me!!!
Say what?
Jim Hupy
On Oct 13, 2016 7:41 AM, "Adam Metzger" wrote:
> Multimeter readings show 545 on one post and 540 on the other, with
> positive and alternator post.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Gmclist Info Page - list.gmcnet.org
list.gmcnet.org
To see the collection of prior postings to the list, visit the Gmclist Archives. Using Gmclist: To post a message to all the list members, send email ...
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Gmclist Info Page - list.gmcnet.org
list.gmcnet.org
To see the collection of prior postings to the list, visit the Gmclist Archives. Using Gmclist: To post a message to all the list members, send email ...
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
| Re: [GMCnet] Inherited a GMC! Hello and please help me!!! [message #308676 is a reply to message #308675] |
Thu, 13 October 2016 10:14 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
|
Senior Member |
|
|
I would set your multimeter on 20 volt D.C. Place the black probe on the
aluminum plate that the isolator is bolted to. Place the red probe first on
the center binding post. With the engine running, you should see 14.5 Volts
more or less. The upper post as well as the lower post should ideally be .5
-.7 volts less than that. If not, report back. We can help from there.
Jim Hupy
On Oct 13, 2016 8:06 AM, "D C _Mac_ Macdonald" wrote:
> My guess is that writer is measuring between center post and outside posts.
>
> Auto-ranging digital multimeter is showing 540 and 545 millivolts which is
> GOOD (showing the voltage drop across the diodes)!
>
>
> ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
> ~~ ~ D C "Mac" Macdonald ~ ~~
> ~ ~ Amateur Radio - K2GKK ~ ~
> ~ ~ Since 30 November '53 ~ ~
> ~ ~ USAF and FAA, Retired ~ ~
> ~ Member GMCMI and Classics ~
> ~ ~ ~ Oklahoma City, OK ~ ~ ~
> ~~ ~ ~ "The Money Pit" ~ ~ ~~
> ~ ~ ~ ~ TZE166V101966 ~ ~ ~ ~
> ~ ~ ~ '76 ex-Palm Beach ~ ~ ~
> ~~ k2gkk + hotmail dot com ~~
> ~ www.gmcmhphotos.com/okclb ~
> ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
> ______________
> |[ ]~~~[][ ][]\
> "--OO--[]---O-"
>
>
>
>
> ________________________________
> From: Gmclist on behalf of James Hupy jamesh1296@gmail.com>
> Sent: Thursday, October 13, 2016 09:53
> To: gmclist@list.gmcnet.org
> Subject: Re: [GMCnet] Inherited a GMC! Hello and please help me!!!
>
> Say what?
> Jim Hupy
> On Oct 13, 2016 7:41 AM, "Adam Metzger" wrote:
>
>> Multimeter readings show 545 on one post and 540 on the other, with
>> positive and alternator post.
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> Gmclist Info Page - list.gmcnet.org gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org>
> list.gmcnet.org
> To see the collection of prior postings to the list, visit the Gmclist
> Archives. Using Gmclist: To post a message to all the list members, send
> email ...
>
>
>
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> Gmclist Info Page - list.gmcnet.org gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org>
> list.gmcnet.org
> To see the collection of prior postings to the list, visit the Gmclist
> Archives. Using Gmclist: To post a message to all the list members, send
> email ...
>
>
>
> _______________________________________________
> 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
|
|
|
|
| Re: [GMCnet] Inherited a GMC! Hello and please help me!!! [message #308677 is a reply to message #308671] |
Thu, 13 October 2016 10:26 |
k2gkk
Messages: 4452
Registered: November 2009
Karma: -8
|
Senior Member |
|
|
Hi, Adam.
From your words below, I believe you are using the multimeter incorrectly.
You should be measuring ALL voltages with respect to the chassis ground.
Measure voltage at each of those three terminals on the isolator.
See my earlier message where I stated that I assumed you measured the outer
terminals with the negative test lead on the center terminal. IF I assumed
correctly, your isolator is good.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ Since 30 November '53 ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ Member GMCMI and Classics ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ~ TZE166V101966 ~ ~ ~ ~
~ ~ ~ '76 ex-Palm Beach ~ ~ ~
~~ k2gkk + hotmail dot com ~~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
______________
|[ ]~~~[][ ][]\
"--OO--[]---O-"
________________________________
From: Gmclist on behalf of Adam Metzger
Sent: Thursday, October 13, 2016 09:32
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Inherited a GMC! Hello and please help me!!!
Multimeter readings show 545 on one post and 540 on the other, with positive and alternator post.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Gmclist Info Page - list.gmcnet.org
list.gmcnet.org
To see the collection of prior postings to the list, visit the Gmclist Archives. Using Gmclist: To post a message to all the list members, send email ...
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
|
|
|
|
|
|
Goto Forum:
Current Time: Tue Oct 01 23:28:02 CDT 2024
Total time taken to generate the page: 0.06875 seconds
|
GMCforum
Search
Help
Register
Login
Home
