The Clymer manual outlines a test procedure whereby an off-idle speed voltage is taken from the B+ terminal of the diode board and the D+ terminal of the alternator brush assembly and compared to the off-idle speed voltage from the D+ terminal on the diode board and ground. My understanding is that the D+ terminal on the diode board is on the backside where the three alternator wires attach. How to you access the D+ terminal of the board while the engine is running???
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Testing A Diode Board '91 R100GSPD
- Thread starter leafman60
- Start date
I can't help specifically, but you might try these other sources and combine the info into a clearer picture:
https://robfrankham.com/diode-board-test
https://bmwmotorcycletech.info/trbleshootALT.htm
There are some similar subjects in the Similar Threads pane below, but there aren't many extensive postings.
https://robfrankham.com/diode-board-test
https://bmwmotorcycletech.info/trbleshootALT.htm
There are some similar subjects in the Similar Threads pane below, but there aren't many extensive postings.
pglaves
#13338
You should buy Rick's little book on the Airhead charging system.
stevenrankin
Active member
Out of print
Good luck finding Rick's book new as it is out of print. I have been waiting over a year now for my copy from Rick. I keep waiting because it is a very good book. I haven't looked for a used copy hoping Rick gets enough interest to have more printed. St.
Good luck finding Rick's book new as it is out of print. I have been waiting over a year now for my copy from Rick. I keep waiting because it is a very good book. I haven't looked for a used copy hoping Rick gets enough interest to have more printed. St.
I have a charging problem and I am trying to locate the source.
In the middle of a cold dark night, miles away from anywhere, my charge light popped on and wouldn't go off. I made my way back to civilization and I am now trying to troubleshoot the problem. The charge light comes on when the key is turned on. I think my rotor is ok. While running, the charge light no longer stays brightly on but seems to linger at about half intensity.
I am checking my regulator as well as the diode board for malfunctions or bad connections.
.
In the middle of a cold dark night, miles away from anywhere, my charge light popped on and wouldn't go off. I made my way back to civilization and I am now trying to troubleshoot the problem. The charge light comes on when the key is turned on. I think my rotor is ok. While running, the charge light no longer stays brightly on but seems to linger at about half intensity.
I am checking my regulator as well as the diode board for malfunctions or bad connections.
.
Yes, the brushes look okay. I am just going through and trying to test every part of the charging system. The bike has very low miles on it, 6-7k.
.
guenner
Member
To check the diode board it is easy with a multimeter with a diode check function.
Disconnect all wires from the diode board.
Put the leads on either side of a diode and you should get a readout of ~0.5V on one side and 0V on the other side for a good diode.
Without a multimeter use a 12V bulb like one for the brake/turn/tail light. Connect one side to battery minus and the other side to a pin of the diode. The other pin of the diode should be on plus of the battery. Repeat the test by switching the bulb and minus on the pins of the diode. The light should come on in one test and completely off with the other test if the diode is OK.
Test 1: battery+ -> [pin 1] diode [pin2] -> bulb -> battery-
Test 2: battery+ -> [pin 2] diode [pin1] -> bulb -> battery-
/Guenther
Disconnect all wires from the diode board.
Put the leads on either side of a diode and you should get a readout of ~0.5V on one side and 0V on the other side for a good diode.
Without a multimeter use a 12V bulb like one for the brake/turn/tail light. Connect one side to battery minus and the other side to a pin of the diode. The other pin of the diode should be on plus of the battery. Repeat the test by switching the bulb and minus on the pins of the diode. The light should come on in one test and completely off with the other test if the diode is OK.
Test 1: battery+ -> [pin 1] diode [pin2] -> bulb -> battery-
Test 2: battery+ -> [pin 2] diode [pin1] -> bulb -> battery-
/Guenther
I spoke with Rick Jones (Motorrad Elektrik) yesterday and he advised to ignore the Clymer manual and simply do a straight diode test of all diodes on the board. That's easier done with the board on the bench so that's my intention. There's even one or two Youtube videos showing this.
.
stevenrankin
Active member
Omega
To be honest, if you don't ride with a ton of electrical clothing, heated hand grips, gloves, and lights, you may not need the Omega system. The stock charging system works fine for what it is. Rick sells replacement diode boards and they would be cheaper and better than the BMW unit.
I ran my stock charging systems for 200K miles and 130K miles on my two airheads changing up to the higher output systems when I started using electric heated clothing.
Thanks for letting us know how your problem turned out, it is nice to have some take the time to report the findings of their work, so few do. Cheers, St.
To be honest, if you don't ride with a ton of electrical clothing, heated hand grips, gloves, and lights, you may not need the Omega system. The stock charging system works fine for what it is. Rick sells replacement diode boards and they would be cheaper and better than the BMW unit.
I ran my stock charging systems for 200K miles and 130K miles on my two airheads changing up to the higher output systems when I started using electric heated clothing.
Thanks for letting us know how your problem turned out, it is nice to have some take the time to report the findings of their work, so few do. Cheers, St.
Yeah, I haven't decided for sure yet. I do like to ride on dirt and that happens often in cooler weather. Having some electric gear in those situations can be nice. However, the lower speeds typical of such riding cause the alternator to produce less power to support the electric gear. Of course the lower speeds mean less cold wind exposure too.
I may just replace the diode board and eventually sell the bike since I have too many anyway. It's a cherry example that's just now turned 8k miles.
.
stevenrankin
Active member
Selling
Makes sense if you are thinking about selling it to just replace the diode board. You won't get the money back for installing the higher price charging system. Personally I would only install the higher output system if I were going to ride for awhile and put it to use. St.
Makes sense if you are thinking about selling it to just replace the diode board. You won't get the money back for installing the higher price charging system. Personally I would only install the higher output system if I were going to ride for awhile and put it to use. St.
pglaves
#13338
I think Rick includes one or two additional items like solid mounts with his kit.
He is a local boy for me and has spent lots of time giving advice to me and others over the years for free.
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