Newell Gurus

Full Version: Alternator conversion
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
Pages: 1 2
Merry Christmas and Happy New year to all.

My 300 amp alternator went out so I replaced it with a new one but the new one has an internal regulator and the old had an external Pentex PX 4000 regulator. The shop that sold me the new one gave me a diagram and explained that I only need the blue ignition wire in addition to battery and ground but did not mention doing anything with the existing regulator. It is not working properly and I now believe I was supposed to disconnect the wires from the old regulator but not sure what to do with them. Has anyone else dealt with this?

Thanks
Dario and Andrea Perini

#581 2001 45'8"
What did you use for the ignition wire? Have you taken a voltmeter and confirmed it has 12Pos when the ignition is on, and nothing when the ignition is off on the wire you tapped for the blue wire.

The reason I ask is that I have never understood how Newell wired the voltage regulator, and I have found wires I that were hooked to the alternator or voltage regulator to be neatly tucked into the wiring cover and neatly terminated.

Meaning you could have used one of these phantom wires and not providing an “on” signal to the alternator.
Hi Richard, how are you doing?

I have attached the brown wire running from the keyed ignition and attached it to the blue wire that goes to the ignition post at the back of the new alternator. It is working with the key on but I am only getting 9.8 volts not the 12 needed to start the alternator. With the key off, I am getting nothing. Not sure where the voltage drop is, any advice?

Dario
Check all connections including ground.

You might try to make a jumper wire directly from the battery terminal to the ignition post on the alternator to confirm this is the problem.

Not trying to be a smart aleck here. You said your alternator went out. And now the new alternator is not working. Hmmmmmmm. Tell us how you determined the alternator was not working?

And have you checked the output of the new alternator on high idle? Does it change?
When the coach was at Newell, they diagnosed it as a bad alternator and I also had it tested on the bench before buying the new one. It was also tested and works fine on the bench. I plan on jumping from the battery post to ignition post tomorrow, will let you know how it works
Thanks

Dario
One more thing to check, and if I am being too elementary, then forgive me. I would put my voltmeter on the pos and neg terminals of the alternator while the engine running and compare those voltages to voltages without the engine running. It is as close as you can get to isolating the alternator from the rest of the system. Perhaps you have done this already.

If you don’t want to reach in there with belts a whirring, then make two jumpers with alligator clips to attach with the engine quiet.
Richard, when I use the jumper wire from battery to ignition post on the alternator, should I disconnect the wire from the keyed ignition first?
I will try to do everything today.
Thanks
Dario
Not necessary since you already confirmed voltage on the existing wire.
Is there a voltage sense wire on the diagram they gave you?

And disconnect all the wires from the old regulator
No sense wire and old regulator is disconnected.
Thanks
Dario
Pages: 1 2