Charging problem...this SHOULD be easy, FIXED!

[AKcharger]

OK guys this should be easy but I'm stumped. car started discharging on Friday here's what I did:
- Replaced alt (bad diode) still bad
- New voltage AND good grounds...still bad
- Checked power at ballast resistor per repair manual 11.56 volts...so wires and ballast resistor good
- Cleaned Batt terminals and cleaned ground wires at solenoid...still bad
- On Alt I get 11.56-11.61 on both "field" terminals
- on the "batt" post I get .31 volts...is that the smoking gun? it's brand new?? I tried it a few times .31-34
- shoot wires going into the voltage regulator while running 11.56-11.64

...Alternator?

I'm missing out on the biggest car show in AK because of this 

[John_Kunkel]

What is the battery voltage when you're taking the various voltage readings? Are the readings the same as the battery voltage?

The .31 volts at the alternator battery post is a big flag. What is the voltage at the large threaded lug on the stater relay?

[AKcharger]

- OK at battery, starter solenoid post and the batt post on the ALT with engine off 12.84( I swear i did it the same as before..now it shows over 12 volts)

- With car running batt still around 12.49, solenoid post 12.49 and post on alt down to 12.38-12.39 at idle

- alt gage shows discharge and reving engine does nothing...turn on lights and just drops worse

help!

[1969chargerrtse]

I would rip out the Alternator and run it down to be checked at an auto parts store.  You have voltage on the fields yet it doesn't produce current? 

[2Gunz]

You said you replaced the diodes......


Did you put them in the right way?

They only flow current in one direction.

[Nacho-RT74]

check for 12 volts between green and blue wires feeding alt with key in RUN position.

then check for continuity between brushes on alt AND NO CONTINUITY between any brush and chassis ( of course with wires unplugged )... as far I remember a good reading soud it be between 5 and 10 Ohms ( as far My experience, not from manuals )... my average reading is around 6-7 ohms

[AKcharger]

I bought another alternator from NAPA...I know it's supposed to be easy but I've never done it. I'll bring it back to NAPA for a bench test

Nacho let me look at those field wires

[Plumcrazy]

OK guys this should be easy but I'm stumped. car started discharging on Friday here's what I did:
-
- On Alt I get 11.56-11.61 on both "field" terminals


I'm missing out on the biggest car show in AK because of this 

There's your problem right there. The regulator provides the ground for the alternator field.  If it were doing that you would see a much lower voltage at the field terminal that has the green wire.  Probably either the regulator is not working or the circuit between the alternator field and regulator is open.

[71_deputy]

I agree above- check the green wire all the way back to the voltage reg.!!!!!

[Nacho-RT74]

thats why I said check you have 12 volts between field wires ( gren and blue ) with key in RUN

[AKcharger]

AHHHH OK, well it's late tonight guys, I'll check tomorrow.

Oh, brought Alt back to NAPA and it tested good 3x times on the bench

[AKcharger]

OK you guys were right and it was easy, the "new" voltage regulator was bad. Yet again proof that just because somthing is new out of the box doesn't mean it's good. Funny thing is the new/bad one was a $50 top of the line Bendix unit, the new/good one was an $18 NAPA special

Thanks guys...on to the next problem!