Wildguzzi.com
General Category => General Discussion => Topic started by: ritratto on January 12, 2019, 05:22:25 PM
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I have replaced the diod board and the voltage regulator, checked all grounds and the brushes and charge light still will not go off. Starts easy and runs well, but put a multi meter on the battery when running and reads less than 12 volts. Ideas?
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Mine was doing that last week. In my case, one of the 3 prongs on the rectifier was bent down, not connecting to the yellow plug, cutting off 1/3 of the available power from the alternator. Good luck!
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What is the AC voltage coming out of the stator? Is it what the manual states?
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How do you check that Steve?
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Try flashing it. Grab a length of wire and affix one end to the battery positive then rev the engine and touch the other end to the outer slip ring for a few moments a few times and see if the light goes out and it starts to charge.
No, you shouldn't need to flash the rotor on a field excited alternator but with the Bosch system sometimes you do if the system has been sitting idle for ages.
Pete
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If I remember correctly AC voltage is checked from 2 of 3 wires or alt out put spades U, V, W. Marked on ceramic base. You check between two of them, voltmeter set to AC
Have you checked rotor for ohm's? It could have an open wire in it. I have also seen bad solder connections on wires at U, V, W (where 3 yellow wires plug in)
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As Pete says
The alternator is normally flashed by just the tiny current through the charge lamp to 61 on the rectifier and DF on the regulator, if you have changed out the idiot lights for LEDs they don't draw enough current, even the old incandescent lamps were on the low side.
Some of the Guzzi with this charging system were fitted with a resistor in parallel with the charge light to boost the current.
Make sure the regulator ground is well connected.
If you pull the D+ wire off the regulator you should get a good circuit from it to the chassis proving the brushes and wires are ok, just 2 or 3 Ohms I think.
http://www.thisoldtractor.com/guzzi007/schematics/1978_G5.gif
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And I would check your old corroded female crimped on terminal wire ends, check for continuity with the other end of each wire and that they are not cracked and falling apart from age- fatigue or had such a high resistance that the wire has gotten very hot and failed .
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And I would check your old corroded female crimped on terminal wire ends, check for continuity with the other end of each wire and that they are not cracked and falling apart from age- fatigue or had such a high resistance that the wire has gotten very hot and failed .
This happens alot
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To stop the wires corroding dip them in Vaseline before you crimp lugs on and apply it to connectors especially in wet areas, the grease protects the copper from water and oxygen.
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I had trouble & cleaned the ignition connections and the earths - 75 T3. Not sure if your ignition connections impact this? Mine were foul so needed doing regardless.
In my trouble shooting I bypassed the regulator to see if it was faulty, I also didn’t get charge until close to 2k revs, after melting a battery I also learnt to check it peaks out under 14.2v.
When you rev it does the charge pick up at all? I had to replace my rotor/stator. BMW wrote a good help sheet to check both stator and rotor - is on the forum somewhere.
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Ok... a little more background... I replaced the diod board after accidentally touching the positive wire to the negative post on the battery. All was good after that. Rode it for a couple of weeks and then out one night, the charge light came on and would not go off. I checked the brushes, all contacts and grounds and replaced the voltage regulator and no change. 😫
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Ok, since the charge light is on, you have power to the brushes. The "normal" failure is an open stator. If you insulate the brushes from the slip rings, you should have (from memory) :rolleyes: 3 ohms between them. At any rate, check AC voltage at 3500 or so between the 3 yellow wires. It should be around 40 volts or above. If you have that, that rules out the alternator. Report back.
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To stop the wires corroding dip them in Vaseline before you crimp lugs on and apply it to connectors especially in wet areas, the grease protects the copper from water and oxygen.
Did you know in Germany Vaseline is called Weinerslider?
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Yea, use it to lube your shaft splines, like PeeWee!
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I had no end of problems with my T3's charging, replacing both stator and rotor at least twice each. In the end I got really annoyed and bought this
https://www.gutsibits.co.uk/pr/TheShop/index.php?q=brushless+alternator&f=d&Model=6&search=SEARCH
Since the day I fitted it (March 2017) I have had no more problems and, being a permanent magnet it does not rely on the idiot light. Money very well spent!
Incidentally, I did not have to fit the required alternator spacer as it says in the advertisement.
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Did you know in Germany Vaseline is called Weinerslider?
No, but I can't wait to tell my riding buddy.
Ritratto
What happened when you flashed the rotor as per Pete's reply No 4, you should do that with the engine running. If the rotor is ok you will get a good spark off the terminal as it turns the rotor into a strong electro magnet, if the rotor is open or something wrong with the brushes of course you will get no response.
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I tried flashing the rotor the way Pete mentioned and no change.
What is the best method for checking the rotor to see if it is ok.
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Is there continuity between the slip rings? there should be.
Is there continuity between a slip ring and any of the poles of the Rotor? There shouldn't be.
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The slip rings being the two shiny rings that the brushes touch?
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I checked the continuity between the rings and yes, there is. To check to the rotor??? How is this done Pete?
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By poles you mean where the three yellow wires mount? If yes, then no. No continuity.
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For most of the resistance tests mentioned the slip rings need to be isolated from the brushes either by picking the brushes up off the slip rings or insulating the brushes from the slip rings with a small piece of card board or the like, matchbook cover would do.
Brian
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By poles you mean where the three yellow wires mount? If yes, then no. No continuity.
You have to check the ohm's, same w/the rotor. Switch meter to ohm's, check w/cardboard under brushes for rotor and stator w/wiring disconnected.
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I made an easy test diagram when I was having problems with mine. It's a bare minimum on how it all works, but should hopefully help you isolate the issue
(http://scooteropolis.com/images/guzzi/wg/test_diagram.jpg)
Good luck
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Another time when it quit charging the rotor checked out and the problem turned out to be corrosion in the connections, which?? I don't know. I pulled all connections to the diode panel, regulator and every connection I could find, deoxt/cleaded and it cured the problem.
I've cured *many* problems with DeOxit. Most of the time, electrical problems just want to know you care. <shrug> Take them apart, put them back together.. and they magically start working again. Some DeOxit keeps them that way.
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By poles you mean where the three yellow wires mount? If yes, then no. No continuity.
You should get a connection between the terminals on raw stator where the yellow wires connect between each yellow and also between any yellow and Y
You won't get a connection to chassis unless you have a meter with the diode test function.
http://www.thisoldtractor.com/guzzi007/schematics/1978_G5.gif When it opens click on it once more and you will zoom in.
U, V, W & Y are all connected by less than an Ohm.
The wire from Y to the rectifier is optional.
How does it work
A small Voltage is supplied to the rectifier terminal 61 from the charge light
This weak Voltage feeds through the regulator electronics to feed a weak Voltage to the alternator brushes via D+ to DF through the rotor to D- and ground. this weak current turns the rotor into a magnet.
The rotor magnet, spins past the stator inducing AC Voltage into the coils, the rectifier turns this into DC to charge the battery via the B+ terminal.
The 3 small diodes on the left of the regulator rectify a portion of the AC to supply the regulator via D+ to DF, the Voltage on this wire with the motor running should be just over 12
Once the battery reaches about 14 Volts the regulator cuts back on the current going to the rotor, the Voltage coming out of U, V, W cuts back also.
Measure the D+ to DF to chassis and tell us what you see with the key on but not running then at about 1000 revs.
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That's a very nice explanation, Roy. Saved in my "Guzzi stuff" file. :thumb: :smiley:
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To Pete... I checked the continuity between the isolated rings and got a connection. Then from ring to posts ( I’m guessing you mean where the yellow wires attach.
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I have checked the isolated slip rings and have continuity and between the rings and the posts where the yellow wires connect and no continuity.
There are so many many helpful instructions that I am really quite confused by it all. I really understand mechanics and rewired the bike myself, but as to the intricacies of the electrical system, not so much.
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Did you get the Ohm readings cause yes it does matter.
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Ok... so I finally found time to check everything and have basically nothing above .8 on the three circuits and only reading about 3 volts at 3500 rpms. Open stator?
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I made an easy test diagram when I was having problems with mine. It's a bare minimum on how it all works, but should hopefully help you isolate the issue
(http://scooteropolis.com/images/guzzi/wg/test_diagram.jpg)
Good luck
Not to sidetrack from the original problem but I have a question. My 81 CX charging system works whether the dash light is working or not working, I’m not complaining but I thought the system had to have a working light.
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There are basically five parts to the system - rotor, stator, diode board, regulator and the wiring. It's got to be one of those. Since you've already replaced the diode board and regulator, hopefully we can check them off the list.
The most common failure in this system is the rotor opens up. It may check out fine at rest, but when spinning can go open circuit. When I go on trips I carry a spare along with the second most common failure point - the diode board. Haven't needed either, but a friend did need the rotor once.
When checking the stator, was the meter set on AC? One of the leads touching a good ground?
At this point it's most likely the rotor. When removing it after pulling the stator (carefully - and be careful installing it - if it get's cocked going in it'll break) Have a big box padded with shop towels in front of it so when it pops off it doesn't fly onto the floor damaging the slip rings. They don't always fly off, but it's a good possibility.
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My guess...
My CX charging system will NOT work without a working dash light (I also have a volt meter gauge) and as far as I can tell the wiring on mine conforms to the diagrams...stock.
Yours may be modified??
It has been re-wired with a new Lemans I harness from Greg Bender.
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Ah!
That's probably the answer.
I've had my ('81 CX) charging system go down twice and the volt meter saved me from grief and both times I made it to the barn.
I figure that some clever owner can figure a way to bypass the problem w/out too much pain.
Volt meter works for me.
:-)
My original dash is long gone, but I did like the voltmeter. I just changed the dash from the 1000S clock holders to the standard LM I dash, but the bulb holders are an issue, so I have no idiot lights at the moment.
Anyway, just throwing this out there to the original post. I chased a charging problem on My CX for almost a year, and I finally found the problem. There was a hairline crack in one of the bush holders that kept it from making good contact. Once replaced, everything worked fine.
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If you had 3 ohm at rotor slip rings then it's the stater. .3 ohms at 2 of 3 phase output wires (3 prong plug) is what stater should be with all wires unplugged and cardboard under brushes.
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"If you had 3 ohm at rotor slip rings then it's the stater."
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Not necessarily, Steve. There is a possibility resistance goes infinite once the rotor starts spinning.
I don't know how to test for that one.
The test for the regulator is to bypass it. If the system now works (but voltage keeps going up the higher the revs) you know it's the regulator.
Stators - a good resistance check should be good enough.
If you don't have a spare rotor, it's a good idea getting one. Hard acceleration and deceleration are the killers - big changes in inertia loosen the windings leading to broken connections. That's probably a reason for Ducati going to the permanent magnet system.
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everyone step back I can fix this without looking from 2000 miles away..... :popcorn:
Check the length of the brushes. A friend w LM V had on off charging light issues. It always looked like the brushes were seated firmly on the rotor. He is a great mechanic, but Fooled Again, they were just floating close to the rotor and not firmly seated. Worn, short was the problem. The springs had bottomed out on the fixture and not pushing the brushes fully seated onto the rotor anymore. Rotated the brushes so they weren't at 12 o'clock, too...
Fixed. See, amazing uh?..... :grin: howz it running now?
It's really funky to see how hidden this is. It'll look all good but it's in the last .01 w the spring bottomed.
Good luck, all the best. I have run a second ground wire off the diode to the engine case...it helped and found another 1/4 to 1/2 voltage....using the adjustable voltage regulator?
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When reassembling my T3 from a frame powdercoat i chased a charging problem for several weekends. It ended up being two wires on the wrong terminals on the stator. I had checked the wiring 20 times. I Ohm'ed the rotor, I phased the rotor, I changed the rotor, with a known working one, I changed the diode board and still no charging. Then when stepping back in frustration then came back with a clear head and really compared the pre-disassembly photos with the way the stator was connected. I had 2 wires switched. Some of this old wiring its hard to determine what color they truly are and its easy to confuse dark blue for black or some greens for blue.
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When reassembling my T3 from a frame powdercoat i chased a charging problem for several weekends. It ended up being two wires on the wrong terminals on the stator. I had checked the wiring 20 times. I Ohm'ed the rotor, I phased the rotor, I changed the rotor, with a known working one, I changed the diode board and still no charging. Then when stepping back in frustration then came back with a clear head and really compared the pre-disassembly photos with the way the stator was connected. I had 2 wires switched. Some of this old wiring its hard to determine what color they truly are and its easy to confuse dark blue for black or some greens for blue.
Yep. A guy called me to look at one after he was totally frustrated. He'd changed rotors, stators, diode boards, regulators, and it still wouldn't charge. He had the +on the wrong terminal. <shrug>
everyone step back I can fix this without looking from 2000 miles away..... :popcorn:
that's a fact..
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I recently made the exact same mistake...took me a good while to realise as the cable colors were wrong!