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Hi everyone.
Does any one have experience in alternator diagnosis and repairs by bench testing?
I have repaired one for a Mazda RX7 by changing both the rectifier and the regulator. The rectifier comes with the diode trio and the regulator has the brushes built in. Everything is looking good except there is a persistent fault "Lamp Init" which I cannot seem to locate and resolve.

Thanks in advance

What is 'Lamp Init'?

what condition is the comm in ? did you take it apart and check the windings and there resistance ? what year ? it could of well started to delaminate and the resin is breaking down if its a early rx

not 100% but later cars may of had ecu controlled alternators

Year and Model ??


edit. have you check the output of the actual alternator with a meter have you tested the wiring for the sw-live

kellys_eye wrote:What is 'Lamp Init'?

Alternator/battery light on the dash

Is the ignition lamp wired correctly? i.e. to terminal 1 on the alternator? Are you using the correct bulb? One of too low a current may cause it to light no matter what.

Best check is in-situ. On the bench, if you can wind it up to the appropriate revs, you should get the usual 14.4V on 'charge'. Load it up to see how it drops off and check against manufacturers ratings.

Awesome guys. Just awesome.

It is a 1990 model.
The stator is okay. I checked for resistance and it's good.
It charges up to 14.4 V. With the load 12.6 V about.

I think Kellys_eye's question has nailed it for me. The BULB I am using is probably low volt. It reads 2.5v on the test. Like he said if it is low, it will light up no matter what. I am hoping on the car it will be a higher voltage and it will go off.

Phew.... that is a great answer to all my wondering.

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******** wrote: It charges up to 14.4 V. With the load 12.6 V about.

What kind of load?

Dropping to that level (12.6) means the maximum load presumably (which is what?.... 45A???)...... which is a good test, for sure, but if it's not the rated maximum and it's falling to that voltage then you need to check elsewhere.

If that's a bench test it should be about right the real test will be in car under real load conditions

@ K_E ...You are correct. That is the load on the Bench Tester

@ Bob ..... Yes I believe the real conditions will prevail in the car itself.

Thanks everyone.

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