Electrical gremlins again (crazy needle syndrome)

[urq]

Neither of the handheld meters have a diode when measuring DC either ... 

I don't understand what might make the dash meter jump ... maybe there's a
bad connection inside that is causing the jumping in particular voltage
ranges.  When you've got two handheld meters telling you there isn't likely
anything wrong they are likely the ones telling the tale ... 

If you suspect alternator diodes then test them directly, don't infer
there's a problem based on a voltage fluctuation ...

Steve Buchholz

-----Original Message-----

The voltmeter in the dash possibly doesn't have a diode or such to  
keep the AC voltage out. The handheld meter when set to read DC  
voltage will read ONLY DC, likewise with AC. He stated he's getting a  
whole bunch of AC voltage which could make the dash meter fluctuate.  
I'm not saying the dash unit isn't bad, but all that AC in there is  
certainly no good.

Didn't OP state that the dash meter is stable with the engine off?

-Cody (mobile)

On Jun 6, 2010, at 7:45 PM, "urq" <urq at pacbell.net> wrote:

> ... I thought I read that with external analog and digital meters the
> voltage was stable ... why are people continuing to recommend  
> anything other
> than replacing the voltmeter in the dash?
>
> Steve Buchholz
>
> -----Original Message-----
>
> Another vote to check out the alternator, even if it was recently  
> rebuilt.
> My son's car ('91Golf) had a recently rebuilt alternator in it and had
> similar problems.
> As it turned out the first problem was that the filed wiring was not
> soldered in properly to one of the slip rings. In another year the  
> soldering
> for one of the rectifying diodes let go.
> Clearly shoddy workmanship.
> The car was bought secondhand and came with the rebuilt alternator and
> starter.
> I also had to fix the rebuilt starter, that was also nearly brand  
> new, there
> was hardly any wear on the commutators.
>
> Good luck, Peter