So I am working on a 1992 hmmwv. Put on a dual voltage alternator. Not charging, found no 24 volts to ign post. found the kds box was bad. replaced that with a Nartron box, now the wait light works and i have 24 volts to the ign post. still no charge. I have no volts out of the a/c tap wire or post. should i have volts going to that or coming out, not a bunch of info. we got used newer alternator and robbed the regulator off, still not charging. this was the original problem. Cant use the alt due to it has a serp pully and mine is v belts. any info or if there is a way to check the alt to see if its bad. For wiring i have large wire to main stud on alt and the ground wire from truck to ground stud on alt, and the ground strap to same stud and to the stud on bracket. then wire from truck to ign post, i have the other wire capped off. and the tap wire going to the a/c tap. did not put anything on the 14 volt to test yet. was told if you ground it it takes out the 12 volt side. dont want to fry anything. any help or info, thanks chris
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200 DUAL VOLTAGE ALTERNATOR PROBLEM
- Thread starter CHRIS. B
- Start date
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- Rosamond, CA
Free info. > https://tfsweb.tamu.edu/uploadedFiles/FRP/New_-_Local_Capacity_Building/TM-9-2320-280-20-1 Maintenance Manual M998 Series HMMWV Vol 1.pdf
More free info.
Make sure the fuse link is good. Looks like a washer on the 24 Volt output bolt. Goofy fusey thing.
Must have lead "568A" the 8 ga wire hot in run position. This powers it up.
AC tap is a signal output and no voltage until spinning. (dirty signal with AC & DC components to let PCB / EESS box know engine is spinning)
Not something to worry about in this case.
Ground strap... of course.
May take a few moments to output. Understand there is a "delay on" feature. ???? Advise
Shinny new means nothing... tested reassuring.
86humv sent the pictures. Worth a thousand words.
Read the TM above. Thousands and thousands of words. At least thumb thru it for more pictures, CAMO
More free info.
Make sure the fuse link is good. Looks like a washer on the 24 Volt output bolt. Goofy fusey thing.
Must have lead "568A" the 8 ga wire hot in run position. This powers it up.
AC tap is a signal output and no voltage until spinning. (dirty signal with AC & DC components to let PCB / EESS box know engine is spinning)
Not something to worry about in this case.
Ground strap... of course.
May take a few moments to output. Understand there is a "delay on" feature. ???? Advise
Shinny new means nothing... tested reassuring.
86humv sent the pictures. Worth a thousand words.
Read the TM above. Thousands and thousands of words. At least thumb thru it for more pictures, CAMO
Ok this is my wire set up. I have 24.7 to alt on the 568 and on the larger wire for the upgrade. It has the washer. I let fun for 10 minutes still 24.7. I am from the auto side so not to much with 24 volt system. I found a site that shows how to check the alt so I will try that. But it also says it wants deep cycle batteries. This has 2 gam. Could that be a problem
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- 1,710
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- Rosamond, CA
Snap a overall picture. Where's the 14 volt lead connected? How about the fat 24 volt. that's the one with the goofy fuse washer. Your wires look correct on the regulator. IGN and AC Tap. Got 24 Volts on the IGN when running? Disconnect and check to see if the wire has 24 Volts in the RUN position. If 24 V... time to look a bit deeper.
Inspect the connectors for frayed or broken parts/ pins / wires.
IMO wouldn't be to concerned about batteries chemistry. Just know what one as and they are good. (OK if starting truck)
Excite the alternator (IGN) "568", spin the alternator fast...Output to batteries. 12 or 24 volts same oh same OH for operation so you'er OK. Those alternators are a very robust and bushiness design. Regulator that's another story. Nothing to see inside... R&R.
Another check... walk the # 8 "IGN"wire back thur the ENGINE harness to the PCB / EESS box and check that business out.
Hard / challenging to work electrical issues over the internet with out slicking my nose and mulitmeter in there myself.
Mulitmeter, eyes and TM are the tools.
Tangled up in wires, CAMO
I want to thank you all for your input an the link for testing. It shows i have a bad alt. i have a used one here and it ohms out good have not put power to it but it passed the test mine failed. The only problem is it is set up for serp belt and mine is v belt. Can i swap pulleys, the v belt is keyed and the serp is not. Dont know if it will work, any info or do i need a different pulley for this alt.
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Interesting that the Alt is bad. Most report it is the regulator.
Thanks for the update,
Thanks for the update,
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Here we go again, 568 is not used on the 200A alternator, 5A (what would go to the output of the 60A alternator) is connected to the exciter input on the 200A alternator 568 will not properly handle the field current required by the 200A alternator , the 24V output goes directly to the battery on the 200A alternator setup, this also eliminates the reverse polarity protection that the original 60A system had.
- 1,710
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- Rosamond, CA
YOU ARE RIGHT !!! Should have caught that. I had the drawing in hand.
BUT all is good . Tthe pictures shows the # 8 ga wire going to excite / regulator. You can see see the 568 taped back. Bear has 2020 vision. OP didn't ness with wires, just R&R. Sooo all is good.
Bear at left just got spanked, CAMO
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