Please review my Alternator Troubleshooting logic

[kerravon]

Hello world. I am looking for help in diagnosing a compufire alternator on a 1990 Australian GL1500 which is not charging the battery. I have done a number of tests to try to diagnose the issue and would like someone who knows about GL1500 charging system to check my logic and see if I am missing anything obvious.

Background: I removed the previous alternator (which was working normally) to upgrade to a compufire. I installed the compufire following the instructions supplied and following a youtube video mentioned in another alternator thread on this site. Also installed new AGM battery and 2 x dogbone (main) fuses as recommended by compufire. AGM battery is fully charged and shows +12.6V with ignition off.

Problem: No output from alternator at any RPM. Multimeter DC voltage across battery terminals is 12.6 with engine running at all RPMs. Multimeter DC voltage with Red probe on B+ output post of alternator and Black probe on battery negative post or alternator case is also 12.6 with engine running.

Tests done: Main fuse and all fuses in fuse box are all good (as shown by continuity test with multimeter and visual inspection). Replaced all relays in relay box next to fuse box with the relays suggested by wingadmin. Multimeter continuity test shows that B+ output post of alternator is continuous with battery positive post, and case of multimeter is continuous with battery negative post. Multimeter DC voltage test shows 12.6 volts on both sides of alternator exciter wire connector when ignition is on, and 0V on both sides of connector when ignition is off.

Conclusions:
1. because:
a) the previous alternator worked normally
b) no fuses in the fuse box are blown and the main fuse is not blown and the bike starts normally
c) a new relay 8 has been installed
d) the alternator B+ post and battery positive and post are continuous when tested with multimeter
e) the alternator case and battery negative post are continuous when tested with multimeter
e) the DC volts measured at B+ output post on alternator and battery ground are 12.6 when engine is running at 2000rpm
therefore, the problem is with the alternator/regulator, or exciter voltage input to regulator from the alternator side of the exciter wire connector, and is not being caused by the wiring/fuse/relay between the alternator and the battery

2. because there is +12.6volts on both sides of the exciter voltage connector, this indicates that the problem is either:
a) there is a break in the wire between the alternator side of the exciter wire connector and the regulator, meaning the regulator is not getting any sense voltage
b) the regulator is defective
c) the alternator is defective

Questions:
1. I noticed that the exciter wire connector only has one spade terminal and 1 wire even though it is a dual post connector. I assume this is the case because the ground is provided by the chassis / alternator case. Is that right?

2. I guess the obvious next step is to reinstall the old alternator to see if it works. Before I go through the hassle of doing that, based on the test results above, can anyone see any possible causes of the problem apart from those listed above?

Thanks world!

[Swagonmaster]

It looks like you have covered the bases pretty well. If you have ever seen an alternator tested at a shop they only need to hookup to the B+, the excitor wire and ground the case to test the unit so since you have tested at the posts everything else on the bike can be ignored. Sometimes even new parts don't work.

[kerravon]

Thanks Swagonmaster, I agree with what you say. I guess I need to put the old alternator back in and see if it works. Cheers.

[DenverWinger]

If the exciter connection on the Compufire has two terminals and the connector from the bike only has one, check to see if you are applying exciter voltage to the correct terminal....

[kerravon]

If the exciter connection on the Compufire has two terminals and the connector from the bike only has one, check to see if you are applying exciter voltage to the correct terminal....

Thanks. Good suggestion. I checked and there were originally 2 wires coming from the bike to a 2-pin connector on the bike side of the exciter connector, one of those had already been cut and disconnected as per the compufire install instructions, and the remaining one has the ignition switched 12v exciter voltage. There is also only 1 wire from the compufire side of the connector which goes into the regulator and also has ignition switched 12v exciter voltage.

[samwing1500]

Curious, did the Compufire operate correctly when installed, if so how may miles did it go before you
noticed this problem. Or did it not work at all.
Sam

[kerravon]

Curious, did the Compufire operate correctly when installed, if so how may miles did it go before you
noticed this problem. Or did it not work at all.
Sam

I have been doing an extensive rebuild on the bike and it has been in the shed for the last 1.5 years. I installed the alternator about 6 months ago. I THINK I did a voltage test after I installed it which showed it was outputting good voltage right after the install. I can't remember for sure if I did that but it is the sort of thing I would have done. While the bike has been in the shed, I have run the engine up to operating temp each couple of weeks but have not checked the voltage. I keep the battery charged using a battery tender. When I finally got the bike out on the road for the first time last weekend, the battery went flat after about 45 minutes so I guess the alternator was not working at all during that ride. I've been doing some wiring (GPS, heated grips, CB) as part of the rebuild, but the only thing I did to the stock wiring for that was a) tap into a ignition switched +12V at a white 8 (approx) pin connector on left side near airbox, and b) connect a ground bus to the chassis ground. Can't see how that could cause the issue. I should note that ever since I bought the bike a couple of years ago, the cruise control has not worked. I have replaced the sub air filters.

[kerravon]

Ok, so just in case aliens from the year 2300 are doing an archaeology project about Goldwings in 2022 and need to know how things ended out with this matter, I will advise that I removed the compufire and put the original alternator back in. The original alternator is working normally. This confirms my conclusion that the fault was with the compufire itself, and not the charging system wiring/fuse/relay/battery. I assume/hope that the issue is with the diode in the regulator.

The next question is: does anyone know where the regulator diode in a compufire is?

[Rambozo]

Your typical three phase alternator has 6 rectification diodes. These days it is often all bundled into a unified monolithic regulator.

[kerravon]

Your typical three phase alternator has 6 rectification diodes. These days it is often all bundled into a unified monolithic regulator.

Thanks. Is there any simple way I can use a multimeter to test the regulator / 6 rectification diodes without pulling the whole thing apart? I have unbolted the 3 bolts holding the 2 halves of the alternator together but would prefer not to have to pull it apart further if there is some way I can avoid it.

[Rambozo]

Not really. Some units like Bosch have some test points but most are potted in epoxy so you really can't measure anything. However, by process of elimination you can test the windings of the alternator for opens and shorts to ground. If that is all good, you can be pretty sure the problem lies in the regulator. I have no idea what alternator the Compufire is based on and if you can buy a replacement regulator. Maybe some others here can tell you.
Not sure how Compufire is with warranty work, and if they would work with you or if you have to ship it back, which wouldn't be cheap where you are.

[kerravon]

Not really. Some units like Bosch have some test points but most are potted in epoxy so you really can't measure anything. However, by process of elimination you can test the windings of the alternator for opens and shorts to ground. If that is all good, you can be pretty sure the problem lies in the regulator. I have no idea what alternator the Compufire is based on and if you can buy a replacement regulator. Maybe some others here can tell you.
Not sure how Compufire is with warranty work, and if they would work with you or if you have to ship it back, which wouldn't be cheap where you are.

Thank you, that is helpful

[Swagonmaster]

If there is a starter/alternator repair shop they can both check and likely repair the alternator if sending it back is not a reasonable option.

[kerravon]

That's what I am thinking too. I will post the outcome.

[bellboy40]

I found this information on another Goldwing website. I had read it before and looked it up. The Compufire is an automobile alternator with a different drive end on it to fit the Goldwing.

The Compufire is a Delphi CS121 alternator intended for some Saturns. It has a special drive end casing and drive vane in place of the car parts to enable it's mating to the GL1500 Gold Wing or Valk. It uses a Chicago Rawhide# 9878 seal in the drive end and a Honda O ring fits the nose that goes in the bike. Internally, the rebuild kit for a Delphi CS130 alternator will have everything needed for rebuild unless a new rotor is needed, that also is available at most rebuilders.

[kerravon]

I found this information on another Goldwing website. I had read it before and looked it up. The Compufire is an automobile alternator with a different drive end on it to fit the Goldwing.

The Compufire is a Delphi CS121 alternator intended for some Saturns. It has a special drive end casing and drive vane in place of the car parts to enable it's mating to the GL1500 Gold Wing or Valk. It uses a Chicago Rawhide# 9878 seal in the drive end and a Honda O ring fits the nose that goes in the bike. Internally, the rebuild kit for a Delphi CS130 alternator will have everything needed for rebuild unless a new rotor is needed, that also is available at most rebuilders.

That is great info, thanks!