Alternator Diodes and Rebuild Parts

[maverickfhs]

So I am doing this rebuild as a fun project, already have a carquest/AAP on the car.

One of the shop yesterday said diodes are bad and I watched this video:



DVM in diode setting, I am getting 523 in one direction and in the other it's 0L. So based on this, diodes seem to be good? Unless there's some other way to test it?

Also, I checked on RA and didn't see alternator components/parts to rebuild it.

Is there a particular place, where I can buy regulator, brushes and diode pack? Thank you

 

[eljefino]

Is this for a honda?

 

[maverickfhs]

Originally Posted by eljefino
Is this for a honda?

That's for Acura TSX. Thank you

 

[Chris142]

https://www.aspwholesale.com/index.php?

 

[andyd]

That is a good diode Good in one direction only. Usual mode of failure is to open so that neither side reads

 

[maverickfhs]

Originally Posted by andyd
That is a good diode Good in one direction only. Usual mode of failure is to open so that neither side reads


That's what I thought, no idea why one of the shop said yesterday it needs a diode pack?

 

[kc8adu]

all 6 good?
its a 3 phase fullwave bridge.
that video is worthless.
you could lose 5 of 6 diodes and pass.
got to pull the cover and check all 6.

 

[tom slick]

A voltage ripple test is a better test

http://assets.fluke.com/appnotes/automotive/beatbook.pdf

 

[Linctex]

Originally Posted by kc8adu

that video is worthless.
you could lose 5 of 6 diodes and pass.
got to pull the cover and check all 6.


I agree... you really have to check each diode individually

 

[daves66nova]

Originally Posted by maverickfhs

/quote]

That's what I thought, no idea why one of the shop said yesterday it needs a diode pack?

I know why, to make money off of you

 

[Oro_O]

Originally Posted by tom slick
A voltage ripple test is a better test

http://assets.fluke.com/appnotes/automotive/beatbook.pdf


Yep, he was told that a few days ago here:

https://www.bobistheoilguy.com/foru.../re-rebuilding-an-alternator#Post4958840

Now, there is something to be said for enthusiasm, and he has kept the old one to learn on instead of chucking it. So kudos!

 

[kc8adu]

or just experience.
could be the common failure part.
Originally Posted by daves66nova
Originally Posted by maverickfhs

/quote]

That's what I thought, no idea why one of the shop said yesterday it needs a diode pack?

I know why, to make money off of you

 

[zzyzzx]

I bought diode packs for alternators off eBay.

 

[maverickfhs]

Originally Posted by zzyzzx
I bought diode packs for alternators off eBay.

Thanks, would you have a link for it?

 

[Donald]

You will have 6 diodes in the bridge. I would replace the bridge rather than soldering in replacements. To test the diodes you will need to unsolder one end of each diode then test. Use minimum heat.

Maybe have a couple of other diodes in the regulator circuit.

How did the shop test to say a diode was bad? Hook alternator to oscilloscope? If they did that and said a diode was bad, replace the bridge.

 

[Colt45ws]

Modern alternator testers have a ripple check in them and will condemn an alternator based on too much ripple. Dont need an O-Scope. I dont think any automotive shop has one of those

 

[maverickfhs]

Originally Posted by Donald
You will have 6 diodes in the bridge. I would replace the bridge rather than soldering in replacements. To test the diodes you will need to unsolder one end of each diode then test. Use minimum heat.

Maybe have a couple of other diodes in the regulator circuit.

How did the shop test to say a diode was bad? Hook alternator to oscilloscope? If they did that and said a diode was bad, replace the bridge.

They hooked it up to a machine and I believe it had oscilloscope too. They said, there's a short and diodes are bad.

 

[maverickfhs]

Originally Posted by Donald
You will have 6 diodes in the bridge. I would replace the bridge rather than soldering in replacements. To test the diodes you will need to unsolder one end of each diode then test. Use minimum heat.

Maybe have a couple of other diodes in the regulator circuit.

How did the shop test to say a diode was bad? Hook alternator to oscilloscope? If they did that and said a diode was bad, replace the bridge.

Any idea if I should buy the bridge from ebay or other electronic place? Thanks for the help

 

[Donald]

Originally Posted by Colt45ws
Modern alternator testers have a ripple check in them and will condemn an alternator based on too much ripple. Dont need an O-Scope. I dont think any automotive shop has one of those


The alternator/starter rebuild shops have oscilloscopes. The few I have gone to.

 

[Donald]

Originally Posted by maverickfhs
Originally Posted by Donald
You will have 6 diodes in the bridge. I would replace the bridge rather than soldering in replacements. To test the diodes you will need to unsolder one end of each diode then test. Use minimum heat.

Maybe have a couple of other diodes in the regulator circuit.

How did the shop test to say a diode was bad? Hook alternator to oscilloscope? If they did that and said a diode was bad, replace the bridge.

Any idea if I should buy the bridge from ebay or other electronic place? Thanks for the help

If you have a local alternator rebuild shop buy the bridge there even if more $$ than EBAY.