alternater light flickers
alternater light flickers
'84 r80rt. all of a sudden, today , the alternator light started faintly lighting up and then switching off. The guage would read under 12 then over 12, sporadically. I could detect no difference in operation. But i am nervous driving with that light going on....then going off. Is the alternator going bad? Is battery dieing? how to figure it out?
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Major Softie
- Posts: 8900
- Joined: Tue Aug 03, 2010 1:46 pm
Re: alternater light flickers
You need to put a voltmeter right on the battery while you're riding. Odds are, when the charging voltage drops, but still is there, you've lost a diode on the diode board. There are those who feel comfortable replacing a bad diode, but most replace the entire board. First job is to see what is happening at the battery, then there's lots of instructions here on the site if you search. Make sure you search the old forum and there will be lots of info.
MS - out
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Kurt in S.A.
- Posts: 1664
- Joined: Tue Aug 03, 2010 12:08 pm
Re: alternater light flickers
Could be a hanging brush in its holder or weak springs on the brushes.
Kurt in S.A.
Kurt in S.A.
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Rob Frankham
- Posts: 1240
- Joined: Thu Aug 26, 2010 2:11 pm
- Location: Scotland UK, 20 miles from civilisation up a dead end road!
- Contact:
Re: alternater light flickers
Could be a lot of things... but... it is something. Don't continue riding like that unless you like pushing.
Rob
Rob
Re: alternater light flickers
If you have an analog meter, at idle speed you can actually see the needle swinging if it's a bad diode.
A bad brush/ weak spring will usually cause a non-uniform flicker, a bad diode flicker usually is uniform and the light doesn't go completely out.
If it goes off completely, the comes on again, I'd also look for a bad connection. Maybe even loose connection at the battery! ( I had a broken lug at the battery once...vibration caused it to make and break with weird effect on the engine operation)
A bad brush/ weak spring will usually cause a non-uniform flicker, a bad diode flicker usually is uniform and the light doesn't go completely out.
If it goes off completely, the comes on again, I'd also look for a bad connection. Maybe even loose connection at the battery! ( I had a broken lug at the battery once...vibration caused it to make and break with weird effect on the engine operation)
Clemson, SC
R100s, R75/5
R100s, R75/5
Re: alternater light flickers
i replaced the diode board, but now the generator light doesn't come on at all. When i turn the key to on position, light is out. with the engine running, i should be at 12 to 14 alts, right, now it stays at about 11 engine running or not.
Re: alternater light flickers
The light is part of the charging circuit. If it does NOT come on at all, the alternator isn't charging the battery.
The current for the armature goes thru the light.
Was the replacement board a new one or a salvage? There is a little diode on the back of the board that can be the problem with the light curcuit.
Test: Unplug the DF alternator connection, turn on the ignition switch, then ground the wire you removed. the lamp ought to light.
If it doesn't, something is wrong with the lamp, the wiring or maybe a fuse in that circuit.
If it does light, then do a quick test on the rotor by shorting across the slip rings, which will also directly ground the light circuit. if the light comes ON, you have a faulty rotor.
I think there is a comprehensive trouble-shooting procedure on the Airheads site...what I've mentioned here is just the quickies.
Did you actually test the board for faulty diodes or just change it? Did you check the rotor for faults?
The current for the armature goes thru the light.
Was the replacement board a new one or a salvage? There is a little diode on the back of the board that can be the problem with the light curcuit.
Test: Unplug the DF alternator connection, turn on the ignition switch, then ground the wire you removed. the lamp ought to light.
If it doesn't, something is wrong with the lamp, the wiring or maybe a fuse in that circuit.
If it does light, then do a quick test on the rotor by shorting across the slip rings, which will also directly ground the light circuit. if the light comes ON, you have a faulty rotor.
I think there is a comprehensive trouble-shooting procedure on the Airheads site...what I've mentioned here is just the quickies.
Did you actually test the board for faulty diodes or just change it? Did you check the rotor for faults?
Clemson, SC
R100s, R75/5
R100s, R75/5
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Rob Frankham
- Posts: 1240
- Joined: Thu Aug 26, 2010 2:11 pm
- Location: Scotland UK, 20 miles from civilisation up a dead end road!
- Contact:
Re: alternater light flickers
With all respect, there is nothing on the diode board that will cause the charge lamp to remain out at all times. The current path is ignition switch, Kill switch, Charge lamp, regulator, positive brush, rotor, negative brush to ground. A fault in the diode board may make the lamp stay on all the time or it may flicker but if it is permanently out, it isn't the diode board.Jean wrote:Was the replacement board a new one or a salvage? There is a little diode on the back of the board that can be the problem with the light curcuit.
To find the fault, you only need to check the current path through the components I mention above. At some point, tghere will be a break in the circuit. Sort that out and the lamp will light. Then you can get on to checking whether you've solved the original problem.
Good luck
Rob
Re: alternater light flickers
(Rob. where have you been???)
Glad to see you Rob. You wrote a good discourse on testing the charging cirsuit back in 2007...I printed it and put it in my repair manual. (didn't save it tho, so cannot reproduce it.)
does the little diode work "going the other way?" That is to say, the lamp lights but does not go off if the diode is bad? I had trouble with it once and when I replaced it, all worked well again.
I wonder if ffeldy checked ALL the OTHER possible fault locations before swapping the diode board.
Glad to see you Rob. You wrote a good discourse on testing the charging cirsuit back in 2007...I printed it and put it in my repair manual. (didn't save it tho, so cannot reproduce it.)
does the little diode work "going the other way?" That is to say, the lamp lights but does not go off if the diode is bad? I had trouble with it once and when I replaced it, all worked well again.
I wonder if ffeldy checked ALL the OTHER possible fault locations before swapping the diode board.
Clemson, SC
R100s, R75/5
R100s, R75/5
Re: alternater light flickers
Here is some stuff from Rob that Jean might be referrign to:
Boxer charging - Fault tracing
What do I know about auto-electrics and charging circuits? Well, I can follow a ciruit diagram as long as my daughter is there to tell her colour blind father the difference between a red wire and a black wire. And if it all goes hot and smoky then I know I've make a slight mistake somewhere.
So I ask the experts and Robin Frankham comes up with the goods. He has very kindly put together a tome of wisdom on charging circuits and given permission for the article to be be repeated here, along with the usual caveat on all these articles - no responsibility, your own risk, don't blame me etc, etc.
With the exception of the Regulator, every part of the charge circuit cane be given a simple 'go/no go' test. In fact, most of the bits don't even have to be taken off the bike.
To test the alternator, you need to remove all of the connections to it and pull the brushes away from the slip rings
Alternator Rotor
With a multimeter, check the resistance between the two slip rings. This should be very low and within the spec shown in the manual (sorry haven't a manual to hand at the moment cause I'm at work) but be aware that there are a number of different rotors and that these are 'bolt on' replacements so your rotor might not have exactly the spec shown for your machine. Also check for continuity between slip rings and metal of the rotor. There should be no reading. If there is, the insulation has broken down and the rotor needs to be rewound or replaced.
Brushes
These should be replaced if they are too short. It's quite easy if you're at all handy with a soldering iron. What's too short? No one seems to know... If in doubt, replace, they are cheap. Also make sure you clean the brush holder, this can become covered with dust and short out the field current.
Stator
Thats the bit of the alternator that is bolted to the engine case. Once more, the coils can be tested with a multimeter and the resistance should be within the spec shown in the manual. Again, there should be no continuity to ground.
Diode board
This will have to be removed from the bike. The diode pack is, in fact, eleven seperate diodes. Each one is, in effect, a 'non return valve' for electricity. If you can identify the ends of each diode, you can test for continuity both ways through that component. If you find one that either passes current in both directions or doesn't pass it in either direction, then that diode is fried.
TIP.. if the defective diode is one of the small diodes and you are handy with a small soldering iron, it is quite simple to replace the defective component. A 4A 200V diode is more than adequate and will cost arount 20p (UK) rather than the full cost of a diode board... got to be worth a try, just make sure you put it in the right way round.
Wiring
Check all wiring connections and continuity of all wires. One often forgotten is the main lead from the diode board. This actually connects to the rear of the starter solenoid, to the same terminal as the battery lead. This has been known to work loose.
Regulator
This is difficult to test definitively. the best way to view it is if the charge circuit is working right, then the regulator is OK, if it isn't and everything else has been checked then the regulator must be suspect. There is one worthwhile test if the charge circuit doesn't seem to be working at all. Remove the connector from the regulator and make a link between the lead to the ignition switch and that to the brushes. Start the engine. If everything else is OK. the charge light should go out when the engine is revved (as normal in fact). If this is the case, then the regulator is faulty. (Don't be tempted to ride like this, you will SERIOUSLY overcharge the battery.
Not got a multimeter? In my opinion, this is a 'must have' tool. A perfectly adequate digital meter can be obtained from places like B & Q or Halfords for less than £20 (UK again).
Rob
and:
Testing the Diode Board Bike Index Page
Description
The diode board is basically an assemblage of 11 separate diodes connected together in one package. The main function of the board is to rectify the alternating current produced by the alternator and turn it into direct current that can be used to charge the battery and run the rest of the bikes electrical system. It also has a secondary function, which is to supply, via a separate set of three diodes, the field coil that provides the magnetic field, which is used to generate the output from the alternator. In order to do this, the diodes are arranged as shown below.
Each Diode is a 'non return valve' for electricity and so should pass current in one direction but not the other .In order to test the diodes, you need some form of continuity tester. This can either be a bought tester or a perfectly satisfactory alternative can be made using a battery, a bulb, a couple of crocodile clips and a few bits of wire arranged as shown below. Click here for a note on analogue multimeters.
First remove all connections from the Diode Board. It is actually easier if you remove the board from the bike. Now, referring to the diagram below:-
Connections:
1. B+ Positive line to battery - Thick Red or Black wire (T)
2. Not normally used
3. Thick Wire from alternator to diode board (1 of 3) (U)
4. Thick Wire from alternator to diode board (1 of 3) (V)
5. Thick Wire from alternator to diode board (1 of 3) (W)
6. Wire from D+ on voltage regulator (S)
7. Thin Wire from alternator to diode board (Y)
Procedure
1) Connect the negative clip (marked -) on the continuity tester to terminal number 1 then connect the Positive clip (marked +) to each of terminals 3,4 & 5 in turn. In each case, the bulb should light (or the continuity tester should indicate a circuit).
2) Swop the clips so that the positive clip is attached to terminal 1 and the negative terminal connects to 3,4 & 5 in turn. Now the bulb should NOT light. (The Continuity tester should not indicate a circuit).
3) If you examine terminals 1 & 2 you should find that they are firmly fixed to one of the two metal frames of the diode board. Got to the other metal frame and attach the positive clip to it. Now again attach the negative clip to each of terminals 3,4 & 5 in turn. In each case the bulb should light (I'm going to ignore the bit about the continuity tester from now on, I'm sure you get the picture!)
4) Now attach the Negative clip to the same metal frame and attach the positive clip to terminals 3,4 & 5 in turn. Now the bulb should NOT light.
The preceding four stages test the main rectifier diodes. If the results are not as shown, this indicates that one of these diodes is dead. There's no point in going any further, it's not practical to replace them so you might just as well bite the bullet and order a new diode board. If you've got this far without hitting the problem, then move on to the field diodes.
5) Attach the negative clip to terminal 6 on the diagram and once again connect the positive clip to terminals 3,4 & 5 in turn. The bulb should light.
6) Now put the positive clip onto terminal 6 and the negative clip to 3,4 & 5 in turn. The bulb should NOT light.
That deals with the three field diodes. This just leaves the last two diodes which connect the centre of the 'star wound' alternator into the circuit.
7) Finally connect the positive clip to terminal 7 and the negative to terminal 1. The bulb should light. Now move the negative clip to the same metal frame as mentioned above. The bulb should not light.
8) connect the negative clip to terminal 7 and the positive clip to terminal 1. The bulb should not light. Move the positive clip to the metal frame and the bulb should light.
This completes the diode tests.
It is possible to replace one of the small diodes if you're handy with a soldering iron, and it is certainly a lot cheaper than replacing the diode board. I'd suggest a diode rated at least 4 amps at 100 volts for the job. I have done this. It lasted for at least 20,000 miles and was still going strong when I got rid of the bike. The only thing you have to do is make sure that you put it in the right way round.
R. Frankham Bike Index Page
25/11/2000 (Modified to HTML 15/1/03)
Boxer charging - Fault tracing
What do I know about auto-electrics and charging circuits? Well, I can follow a ciruit diagram as long as my daughter is there to tell her colour blind father the difference between a red wire and a black wire. And if it all goes hot and smoky then I know I've make a slight mistake somewhere.
So I ask the experts and Robin Frankham comes up with the goods. He has very kindly put together a tome of wisdom on charging circuits and given permission for the article to be be repeated here, along with the usual caveat on all these articles - no responsibility, your own risk, don't blame me etc, etc.
With the exception of the Regulator, every part of the charge circuit cane be given a simple 'go/no go' test. In fact, most of the bits don't even have to be taken off the bike.
To test the alternator, you need to remove all of the connections to it and pull the brushes away from the slip rings
Alternator Rotor
With a multimeter, check the resistance between the two slip rings. This should be very low and within the spec shown in the manual (sorry haven't a manual to hand at the moment cause I'm at work) but be aware that there are a number of different rotors and that these are 'bolt on' replacements so your rotor might not have exactly the spec shown for your machine. Also check for continuity between slip rings and metal of the rotor. There should be no reading. If there is, the insulation has broken down and the rotor needs to be rewound or replaced.
Brushes
These should be replaced if they are too short. It's quite easy if you're at all handy with a soldering iron. What's too short? No one seems to know... If in doubt, replace, they are cheap. Also make sure you clean the brush holder, this can become covered with dust and short out the field current.
Stator
Thats the bit of the alternator that is bolted to the engine case. Once more, the coils can be tested with a multimeter and the resistance should be within the spec shown in the manual. Again, there should be no continuity to ground.
Diode board
This will have to be removed from the bike. The diode pack is, in fact, eleven seperate diodes. Each one is, in effect, a 'non return valve' for electricity. If you can identify the ends of each diode, you can test for continuity both ways through that component. If you find one that either passes current in both directions or doesn't pass it in either direction, then that diode is fried.
TIP.. if the defective diode is one of the small diodes and you are handy with a small soldering iron, it is quite simple to replace the defective component. A 4A 200V diode is more than adequate and will cost arount 20p (UK) rather than the full cost of a diode board... got to be worth a try, just make sure you put it in the right way round.
Wiring
Check all wiring connections and continuity of all wires. One often forgotten is the main lead from the diode board. This actually connects to the rear of the starter solenoid, to the same terminal as the battery lead. This has been known to work loose.
Regulator
This is difficult to test definitively. the best way to view it is if the charge circuit is working right, then the regulator is OK, if it isn't and everything else has been checked then the regulator must be suspect. There is one worthwhile test if the charge circuit doesn't seem to be working at all. Remove the connector from the regulator and make a link between the lead to the ignition switch and that to the brushes. Start the engine. If everything else is OK. the charge light should go out when the engine is revved (as normal in fact). If this is the case, then the regulator is faulty. (Don't be tempted to ride like this, you will SERIOUSLY overcharge the battery.
Not got a multimeter? In my opinion, this is a 'must have' tool. A perfectly adequate digital meter can be obtained from places like B & Q or Halfords for less than £20 (UK again).
Rob
and:
Testing the Diode Board Bike Index Page
Description
The diode board is basically an assemblage of 11 separate diodes connected together in one package. The main function of the board is to rectify the alternating current produced by the alternator and turn it into direct current that can be used to charge the battery and run the rest of the bikes electrical system. It also has a secondary function, which is to supply, via a separate set of three diodes, the field coil that provides the magnetic field, which is used to generate the output from the alternator. In order to do this, the diodes are arranged as shown below.
Each Diode is a 'non return valve' for electricity and so should pass current in one direction but not the other .In order to test the diodes, you need some form of continuity tester. This can either be a bought tester or a perfectly satisfactory alternative can be made using a battery, a bulb, a couple of crocodile clips and a few bits of wire arranged as shown below. Click here for a note on analogue multimeters.
First remove all connections from the Diode Board. It is actually easier if you remove the board from the bike. Now, referring to the diagram below:-
Connections:
1. B+ Positive line to battery - Thick Red or Black wire (T)
2. Not normally used
3. Thick Wire from alternator to diode board (1 of 3) (U)
4. Thick Wire from alternator to diode board (1 of 3) (V)
5. Thick Wire from alternator to diode board (1 of 3) (W)
6. Wire from D+ on voltage regulator (S)
7. Thin Wire from alternator to diode board (Y)
Procedure
1) Connect the negative clip (marked -) on the continuity tester to terminal number 1 then connect the Positive clip (marked +) to each of terminals 3,4 & 5 in turn. In each case, the bulb should light (or the continuity tester should indicate a circuit).
2) Swop the clips so that the positive clip is attached to terminal 1 and the negative terminal connects to 3,4 & 5 in turn. Now the bulb should NOT light. (The Continuity tester should not indicate a circuit).
3) If you examine terminals 1 & 2 you should find that they are firmly fixed to one of the two metal frames of the diode board. Got to the other metal frame and attach the positive clip to it. Now again attach the negative clip to each of terminals 3,4 & 5 in turn. In each case the bulb should light (I'm going to ignore the bit about the continuity tester from now on, I'm sure you get the picture!)
4) Now attach the Negative clip to the same metal frame and attach the positive clip to terminals 3,4 & 5 in turn. Now the bulb should NOT light.
The preceding four stages test the main rectifier diodes. If the results are not as shown, this indicates that one of these diodes is dead. There's no point in going any further, it's not practical to replace them so you might just as well bite the bullet and order a new diode board. If you've got this far without hitting the problem, then move on to the field diodes.
5) Attach the negative clip to terminal 6 on the diagram and once again connect the positive clip to terminals 3,4 & 5 in turn. The bulb should light.
6) Now put the positive clip onto terminal 6 and the negative clip to 3,4 & 5 in turn. The bulb should NOT light.
That deals with the three field diodes. This just leaves the last two diodes which connect the centre of the 'star wound' alternator into the circuit.
7) Finally connect the positive clip to terminal 7 and the negative to terminal 1. The bulb should light. Now move the negative clip to the same metal frame as mentioned above. The bulb should not light.
8) connect the negative clip to terminal 7 and the positive clip to terminal 1. The bulb should not light. Move the positive clip to the metal frame and the bulb should light.
This completes the diode tests.
It is possible to replace one of the small diodes if you're handy with a soldering iron, and it is certainly a lot cheaper than replacing the diode board. I'd suggest a diode rated at least 4 amps at 100 volts for the job. I have done this. It lasted for at least 20,000 miles and was still going strong when I got rid of the bike. The only thing you have to do is make sure that you put it in the right way round.
R. Frankham Bike Index Page
25/11/2000 (Modified to HTML 15/1/03)