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DeltaBravo
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Danwvw
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Joined: July 31, 2012
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Location: Oregon Coast
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 Posted: Fri Feb 24, 2017 10:49 am Post subject: Re: Alternator / Battery Light |
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Well the regulator is probably toast now! What is this bus? Is this a type 1 with a aftermarket Alternator? That 76 right! Yeah, the thing you did I would not try. But it did prove the alternator light is good and that it's something else. That green wire shows here as being on the armature. So I would say the Armature circuit is likely open. Could be a brush worn out.
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Last edited by Danwvw on Fri Feb 24, 2017 11:04 am; edited 1 time in total |
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DeltaBravo
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Location: Long Beach, CA
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DeltaBravo
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busdaddy
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Joined: February 12, 2004
Posts: 52736
Location: Surrey B.C. Canada, but thinking of Ukraine
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| Posted: Fri Feb 24, 2017 11:05 am Post subject: Re: Alternator / Battery Light |
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Don't blame the reg yet, it could still be fine. You should have disconnected the plug and grounded the blue wire, but regardless you've proven the light works and the wiring to the front is OK, now check both ends of the red wire for continuity.
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DeltaBravo
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Joined: February 29, 2016
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Location: Long Beach, CA
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DeltaBravo
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Joined: February 29, 2016
Posts: 179
Location: Long Beach, CA
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| Posted: Fri Feb 24, 2017 2:05 pm Post subject: Re: Alternator / Battery Light |
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| busdaddy wrote: |
| Don't blame the reg yet, it could still be fine. You should have disconnected the plug and grounded the blue wire, but regardless you've proven the light works and the wiring to the front is OK, now check both ends of the red wire for continuity. |
OK, well I had to practically pull the alternator to conduct this test. But I tested all three wires (Red, Brown, and green) from Regulator plug to alternator plug. All continuity checks are very good. I also checked the large red cable from the alternator to the battery, it also checks good.
I guess it's time to take my alternator in and have it checked?
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1976 Bus, 2.0 Hydraulic lifters, Manual.
My engine rebuild. http://www.thesamba.com/vw/forum/viewtopic.php?t=656536&postdays=0&postorder=asc&start=0
https://www.thesamba.com/vw/forum/viewtopic.php?p=8444317#8444317
https://www.thesamba.com/vw/forum/viewtopic.php?t=673255&highlight=
https://www.thesamba.com/vw/forum/viewtopic.php?t=674097&highlight=
https://www.thesamba.com/vw/forum/viewtopic.php?t=672791&highlight=
1988 Porsche 911 Carrera Cab
1987 Buick Grand National |
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DeltaBravo
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Location: Long Beach, CA
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DeltaBravo
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telford dorr
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Joined: March 11, 2009
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Location: San Diego (Encinitas)
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| Posted: Fri Feb 24, 2017 5:08 pm Post subject: Re: Alternator / Battery Light |
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3) The other end, I used a wire to poke into the GREEN wire at the regulator.
Opened up my regulator. But It doesn't appear to be the old school type...Solid State?
Is this test confirming I need a new regulator? |
Probably not. Your test is interesting in that it confirmed that the regulator is passing current to the alternator rotor (as it should). As long as the engine wasn't running, you probably did no harm. [If it was running - 'nother story.]
The current at the green wire was supposed to pass through the alternator rotor, then through the brown wire to ground (lighting the light in the process). The rotor is fairly low resistance (a few ohms), so it should have been equal to the wire in lighting the light. The fact that it doesn't points to bad alternator brushes, a bad rotor, or broken connection(s) in the green or brown wires.
Note: the regulator body MUST be grounded for the unit to work (the pin the brown wire is connected to goes to the regulator case)!
And yeah, that regulator defines 'solid state': nothing moves. 
[Another nice thing: that regulator is completely repairable!]
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'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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DeltaBravo
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DeltaBravo
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telford dorr
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Joined: March 11, 2009
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Location: San Diego (Encinitas)
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| Posted: Sat Feb 25, 2017 2:46 pm Post subject: Re: Alternator / Battery Light |
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Grab your ohmmeter. Disconnect the regulator. Measure the resistance between the green and brown wires. If you don't get a low resistance reading, then you have an alternator issue (rotor, brushes, harness, or connections to the front of the alternator).
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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DeltaBravo
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Joined: February 29, 2016
Posts: 179
Location: Long Beach, CA
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| Posted: Sat Feb 25, 2017 2:58 pm Post subject: Re: Alternator / Battery Light |
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| telford dorr wrote: |
| Grab your ohmmeter. Disconnect the regulator. Measure the resistance between the green and brown wires. If you don't get a low resistance reading, then you have an alternator issue (rotor, brushes, harness, or connections to the front of the alternator). |
Just measured,
Is 2.43 M Ohms (2,430,000 ohms) to much?
_________________
1976 Bus, 2.0 Hydraulic lifters, Manual.
My engine rebuild. http://www.thesamba.com/vw/forum/viewtopic.php?t=656536&postdays=0&postorder=asc&start=0
https://www.thesamba.com/vw/forum/viewtopic.php?p=8444317#8444317
https://www.thesamba.com/vw/forum/viewtopic.php?t=673255&highlight=
https://www.thesamba.com/vw/forum/viewtopic.php?t=674097&highlight=
https://www.thesamba.com/vw/forum/viewtopic.php?t=672791&highlight=
1988 Porsche 911 Carrera Cab
1987 Buick Grand National |
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telford dorr
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Joined: March 11, 2009
Posts: 3625
Location: San Diego (Encinitas)
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| Posted: Sat Feb 25, 2017 6:46 pm Post subject: Re: Alternator / Battery Light |
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Wayyyyyy too much. Bad alternator!
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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DeltaBravo
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telford dorr
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| Posted: Sat Feb 25, 2017 9:38 pm Post subject: Re: Alternator / Battery Light |
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Could just be brushes...
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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DeltaBravo
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DeltaBravo
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Posts: 179
Location: Long Beach, CA
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| Posted: Mon Feb 27, 2017 10:50 am Post subject: Re: Alternator / Battery Light |
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Well, I tore the Alternator down. Didn't "see" much that would suggest why it wasn't working. I took some pics. I did note the front bearing was slightly wobbly, didn't feel bad, but the front shaft (armature assembly) wasn't very solid. Rear bearing seemed in better condition.
Brushes; one was significantly more worn than the other. My theory is one spring is suppling more pressure than the other. I don't see any other reason they would wear so differently.
As far as any of the other parts (diodes, winding, exc...) how would I test them?
1-Rear bearing (from Korea)
2-Front bearing (from China)
3
4
5
I can get new bearings, brushes, and slip ring for just over $10 shipped. But I am worried none of this will fix the no charging issue.
And lastly, If my Alternator wasn't charging (I verified with a multimeter while the engine was running) why wouldn't my light in the dash illuminate? This is still confusing me. I feel there is something else I am missing.
Thanks
_________________
1976 Bus, 2.0 Hydraulic lifters, Manual.
My engine rebuild. http://www.thesamba.com/vw/forum/viewtopic.php?t=656536&postdays=0&postorder=asc&start=0
https://www.thesamba.com/vw/forum/viewtopic.php?p=8444317#8444317
https://www.thesamba.com/vw/forum/viewtopic.php?t=673255&highlight=
https://www.thesamba.com/vw/forum/viewtopic.php?t=674097&highlight=
https://www.thesamba.com/vw/forum/viewtopic.php?t=672791&highlight=
1988 Porsche 911 Carrera Cab
1987 Buick Grand National |
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telford dorr
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Joined: March 11, 2009
Posts: 3625
Location: San Diego (Encinitas)
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| Posted: Mon Feb 27, 2017 4:31 pm Post subject: Re: Alternator / Battery Light |
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The dash light only lights when current can flow through the regulator, then through the brushes to the alternator rotor. Once the alternator starts outputting power normally, voltage from the alternator 'diode trio' (the three little diodes) overrides everything, forcing the voltage across the GEN indicator to (near) zero. Thus, the light goes out.
Grab your ohmmeter and measure the resistance between the two slip rings:
It should be a low value.
Also measure from either ring to the rotor shaft. Should be infinite.
If either test fail - bad rotor (e.g. bad alternator).
Otherwise, polish up those slip rings, reassemble, and remeasure the resistance between the green and brown wires, and see if it has changed any.
If the rotor measured OK but the other test fails still, I'd try a new brush holder assembly.
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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I've never rebuilt an alternator, but I am sure I can figure it out. Using some common knowledge and 
