Alternator/Rectifier Internals

[Pawel66]

Could you kindly help me understand:
1. I see 9 diodes on the wiring diagram for the alternator
2. I see in the parts list 3 positive diodes, 3 negative diodes and 3 for exciter
3. In the rectifier I see 6 diodes. Where are the remaining 3?
4. Which ones are positive, negative and those for exciter?

Need to get some fix done on the alternator (it is blinking during idle, voltage produced is ok) I am having it checked, but I wanted to understand what is what.

[Pawel66]

I was thinking about it a bit. Perhaps it is like that:
1. The positive diodes are those with "+" on their housing (hat) while negative ones are those with "-" on their hat.
2. If that is the case, the positive ones are sitting in the rectifier as there is "+" on the plate they sit in. Then the negative ones are in alternator housing underneath, not seen in the pictures I attached?
3. The other ones are the 3 smaller ones seen in the rectifier.

Is it more or less correct?

[ja17]

Seems that I have the Bosch service center test and repair procedures on this somewhere. I try to post it later.

[Pawel66]

Thank you!

[doitwright]

Mike talks about the diodes in this video of a Bosch alternator restoration for a 67 911.

Diodes at the 8:50 mark

https://youtu.be/4ctIvYxpQZg

[Pawel66]

Fantastic video, thank you!

[WRe]

Hi,
the theory of operation with animation see here: https://www.kfz-tech.de/Engl/Biblio/Batterie_Generator/GenSpRegler2.htm.
...WRe

[450sl]

Pawel,

These diodes are especially pressed in because they have to dissipate a lot of heat.
Be sure to replace .

mark

[Pawel66]

Yes, thank you!

I sort of figured it out, then the video confirmed how they fit and both electric connection and, as you say, heat are important there.

I came across a bit of an availability issue with those diodes here. I think I found them (the big ones), but it would. Be good to have part numbers for them from e.g. Bosch as it is difficult to find a match through Daimler PNs.

What I have is:
A 000 548 50 18 DIODE POS.  Bosch 1127320081 - managed to find these, not Bosch, but equivalent
A 001 548 10 18 or A 001 548 11 18 DIODE (-) NEG. Bosch ? sourced from SLS
A 001 548 00 18 or A 001 548 15 18 DIODE EXCITER - this is the more typical one, but I do not know the type/designation; I hope easy to get once you know which one is needed

i will also try to find from the video: negative W04X.28 and positive W04x.29.

[Pawel66]

I think I have the numbers for the main diodes:
Positive Bosch 1127320081 another producer ARD9055
Negative Bosch 0270100354 or another producer ARD9063

That another producer is Alternators, Starters & Parts, just in case.

If anyone knows the parameters/type of the remaining 3 small diodes - I would appreciate sharing, we will have full picture here.

I am enclosing alternator parts list, so that it is here.