Voltage meter spikes intermittently.

[77Z]

I'll take it! The one with Datsun on it.

[S30Driver]

Datsun VR ,  sale pending ....

[Captain Obvious]

2 hours ago, 77Z said:

The one with Datsun on it.

That one is clearly faster.

[Zed Head]

Kind of disappointing.  You had everything in front of you to take the cover off, examine, clean up, adjust, but you went directly to replace.  And you're not even sure that that's the part that needs replacing.  It might be that alternator.

p.s. the multi-quote thing doesn't work, or I would list the quotes that showed the path.

[Zed Head]

On 2/9/2022 at 1:17 PM, SteveJ said:

By the way, if you do happen to have a stock VR, they are adjustable. The cover should be screwed on.

 

On 2/9/2022 at 1:41 PM, Zed Head said:

I maybe the mechanical points can be cleaned up.  Should be fun, usually they just crap out completely.  Worth a shot.

 

On 2/9/2022 at 6:17 PM, 77Z said:

Thanks guys.  Its stock and the original VR.  How can I confirm internal or external?  I've followed the harness from the alternator through the harness apparently to the area under the fusible links and the large black plate where they mount.  Is the VR under this plate?

I've got the service manual and section EE18 and reading that I see the adjustment. 

  Perhaps I have the first month of an internal VR in which case I just need a new alternator.

 

On 2/9/2022 at 3:24 PM, Dave WM said:

I had a problem with my external VR alt on my 75, would spike intermittantly, the fix was a new alternator.

 

Figured it out....

[Zed Head]

At least take the cover off to see how corroded things are inside.  Pleeeeeaaassse.

[77Z]

Didn't know that was possible.  I will do that tonight and let you know. 

[Captain Obvious]

Haha!

I bet the insides look pretty much normal, but would sure be fun to poke around. Somebody (I think it was ZH?) posted a very crusty rusty relay at one point... Don't remember if it was an ignition relay or a seat belt relay, but it said "NFG" on the outside and looked like a boat anchor on the inside. Great pic.

[77Z]

This is a Texas Z so not likely much rust. And it lives in a garage. So we'll see. I'll post pics.  

[77Z]

11 hours ago, Zed Head said:

At least take the cover off to see how corroded things are inside.  Pleeeeeaaassse.

OK, ZH, if this is my VR, it looks beautiful and also solid state. Nothing to corrode, or clean? That's one of the simplest PCBs I've ever seen... couple of resistors, couple of capacitors... and perhaps an adjustment screw there at the paint mark? The PCB base was already cracked. And I'll say that pulling the PCB out of its case, after removing the 1 securing screw, felt damaging to the unit or at least its seal.  So, I'll install S30Driver's unit and see if the intermittent problem resolves (cheap test @ $60). A few days of driving it and results will be obvious.  If spikes persist, I'd seal this thing back up well, including the crack in the front, and reinstall the original.  But then, its alternator time?  My alternator is likely the newest part on my car (installed in 2011).

[Zed Head]

Thanks for the work and the picture.  That would be a replacement then, not original to the car.  The early solid state regulators used to fail often and suddenly, based on what I've read on the various forums.  The potting compound should not be cracked like that.

Rotating machine!

https://www.unipoint.com.tw/

https://www.unipoint.com.tw/about.php

1977 Nissan 280Z is still in their database but there are no parts shown for it.

https://www.unipoint.com.tw/rm_application_search_list.php#

[Dave WM]

and I see an electrolytic cap in there, def beyond life. would be fun to check it for ESR.