VCCA Home Forums TECHNICAL - GENERAL Electrical - 6 volt Did I burn the cutout? - 34 Master

Moving the third brush towards the engine increases the generator output and moving the third brush towards the fender decreases the generator output.

Yep, you might consider converting your old cut-out to solid state and that way you will have the correct mounting on your generator.

Looks like that was short lived. the last few times I used the car it didn't show a charge. So I resoldered the old cutout and put it back on. No difference. Put the diode one back on again, no difference. Polarized the generator, no difference. Thinking it might be the ammeter, I took a reading across the cutout terminals with the engine running and the meter on the 20 amp setting. It reads o.18. Is the generator cooked? If so, where can I get a rebuilt, ready to install replacement? Which other years will fit? I have one for a '53 but I'm afraid to try that in case it is too powerful.

With the car running at a higher RPM than idle, check the voltage output on the generator before the cut-out. If the voltage output is low then the problem is with your generator.

Do you have the correct model of generator on your car? If so, you are probably better off getting the existing generator rebuilt instead of finding a replacement.

You're talking to a dummy here. I need to know between which terminals to test that voltage, and what am I looking for? 6V?

With a multi-meter, put your negative probe on the housing of the generator or on a good ground. Put your positive probe on the cut-out terminal that the generator wire attaches to. You should be reading about 7.5 volts or more depending upon your battery condition.

Thanks. This way I'll be able to eliminate things one by one. My ammeter shows a discharge when the lights are on but no charge otherwise. It either works both ways or not at all is that correct? What I mean, is it possible for it to work on only one half of the scale?

The amp meter should work in both directions. However, it is possible that the amp meter needle could go in one direction but not the other if the needle hangs up on one side of the scale. I have seen that happen. However, from what you describe it definitely sounds like the generator doesn't have any output. With no output from the generator,there would be no charge showing on the amp meter....but if the lights are turned on the amp meter will show a discharge.

And you are correct. The voltage test shows ZIP. I need a generator. Could my newfangled diode cutout have caused this or is it a coincidence?

A diode failure might have caused the problem.....but most likely it was a coincidence that the generator failed when it did.

You do not need another generator. I would suggest getting your generator rebuilt instead.

I realize that JD, but that puts the car out of commission for weeks, during our short driving season. I'll figure something out.

Pat. I can help you figure that out. Move somewhere where you can cruise more during the year. 2 weeks of summer can't be fun. We're on our 7th or 8th month of summer :)
...Joe

Not really. Looking for a rebuilt replacement generator and getting it sent to you could take a couple of weeks (or more) but getting your generator rebuilt at your local generator/alternator shop should only take a couple of days.

That's it, there is no local generator rebuilding. So I have to send it away. Maybe Joe is right, I should move to Tucson.

Ya, sounds like you need to move, especially if you are going to work on an old car. I live in a small community and even we have a local generator/alternator repair shop here.

Received my new generator.



Installed it, joined the two posts shown to polarize and fired up the car. Still doesn't show a charge.But shows a discharge with the light on. Maybe my old generator was good all along? I'll do some of the tests mentioned above and report back.

If the arrow in the photo indicates the two posts that you used to polarize the generator then that is probably your problem. The generator is polarized by connecting one end of a jumper wire to the "Gen" terminal on the diode and then touching the other end of the jumper wire to the "Bat" end of the diode. Your photo indicates that you jumpered from the "field" terminal on the generator housing to the "Bat" terminal on the diode instead.

So both ends of the cutout,is that correct? And how long do I hold that connection?

We have talked about polarizing a generator on Chevy Chatter many, many times in the past. You might want to check out some of the past discussions.

Anyway, yes, you jumper across both ends of the cut-out (diode) as explained above. You jumper across the two terminals momentarily. You should get a spark and the polarizing is complete. Your 1934 shop manual should also show you how to do it as well.

Unless your generator is polarized it will not charge.

OK here's what I did. Jumped across the cutout as per JD, got a spark when pulling one off. Started the car, still nothing on the gauge.

Did the volt check as per JD's post of June 25, shows 0.37. Will clean a grounding spot to make sure and try again.

My multimeter has an ammeter function, up to 10 amps. Tried that across the cutout and got a little over 7. Does that mean anything?

Next time I'm going to my daughter's I'll bring both generators. There is a shop there with an old type tester, both the machine and the guy. If we eliminate the generators then I suppose it has to be the gauge.

If you have output (7 amps) from the generator then you possibly have the wiring wrong or your amp gauge is defective.

Are you getting any voltage to the battery when the car is running?

How do I do that? Wiring was good before, nothing has changed. All this started when the cover of my cutout popped up and shorted out the coil.

As I recall....you checked the voltage at the battery once before. You do it the same as you did it the last time. With the multi-meter set on DC volts, place the positive probe on the positive battery post and place the negative probe on the negative battery post. Then, with the car running at a high idle, check the voltage on the meter.

Sounds more like you have a bad amp gauge. You might want to replace the amp gauge. Or, you can use the amp setting on your multi-meter and check the back of the amp gauge for generator output. If you have amperage there then you obviously have a defective amp gauge.

Voltage at the battery is as such: not running 6.22v, running 6.07. Increasing the idle speed didn't seem to make a difference. I think I have another gauge. I'll try that next.

With the car running you should have around 7.5 volts output going to the battery. That indicates that there is no output from your charging system. However, you said that you were getting 7 amps at your cut-out with the car running.

I assume that your new generator was bench tested by the company that rebuilt it...is that correct?

Okay, try changing the amp gauge and let us know what you find out.

Good luck!

OK.I rummaged and found these two.


Hooked one up & started the engine.....no difference. As a matter of fact it sits exactly like the other one, at a very slight discharge, presumably the ignition.



While I was under there, checked all the fuses I could find. All good or at least they LOOKED good.

Reconnected the original gauge. Then I thought I'd try the new cutout I received today. Same deal.




It still shows about 6.5 amps across the cutout but no voltage between the generator end and the housing.

Learned two things. One. When you've been in your forties for well over 20 years, it takes time to get in and out from under the dash. Two. When you are on your back under there and removing small nuts, keep your mouth shut.

I quit. I'll buy a quick connect battery tender and start a candle burning campaign at church. I may even go see the local shaman just in case.