ND20FA oops! *PIC*

[Paul Carmody]

http://undefinition.googlepages.com/ND20FA.jpg


I seem to have stripped away the color coding that showed which terminal was positive and negative. From this view of the backside, which is which?

Thanks,
Paul

[zachc]

As pictured, left is positive.

Z

[Pete Schumacher ®]

> I seem to have stripped away the color
> coding that showed which terminal was
> positive and negative. From this view of the
> backside, which is which?

> Thanks,
> Paul

Positive would be the left terminal

[tedwilt]

> I seem to have stripped away the color
> coding that showed which terminal was
> positive and negative. From this view of the
> backside, which is which?

> Thanks,
> Paul

The longer terminal is positive. This agrees with the previous posters.

[j_dunavin]

probably not the best idea, but you could take a nine volt and pop the speaker. whichever way the cone goes out is poss. polarity.

[Pete Schumacher ®]

> probably not the best idea, but you could
> take a nine volt and pop the speaker.
> whichever way the cone goes out is poss.
> polarity.

Lots less of a chance of damage too.

[Wolf]

> Lots less of a chance of damage too.

...when the 9VDC heats up the voice coil. I agree- a AAA is plenty.
Later,
Wolf

[johnastockman]

> probably not the best idea, but you could
> take a nine volt and pop the speaker.
> whichever way the cone goes out is poss.
> polarity.

9V is too much, especially for a tweeter...all you need is slight cone movement to tell polarity. The dome of a tweeter doesn't move hardly at all, so you might have difficulty telling, even with a 1.5V...but always use 1.5V. I had more than one person bring me woofers and ask if I can fix them. "What's wrong with 'em?" They said "I used a 9V battery to check if they were working OK cause the cones weren't moving anymore". The cone had moved far enough out so the VC was mis-aligned. A new surround kit with shims fixed one, but the other two were not fixable (by me, anyway).

John A.

[nick29498141]

> ...when the 9VDC heats up the voice coil. I
> agree- a AAA is plenty.
> Later,
> Wolf

Or it would've been my sub, ask Trevor what happened. ;)

NK

[Pete Schumacher ®]

> 9V is too much, especially for a
> tweeter...all you need is slight cone
> movement to tell polarity. The dome of a
> tweeter doesn't move hardly at all, so you
> might have difficulty telling, even with a
> 1.5V...but always use 1.5V. I had more than
> one person bring me woofers and ask if I can
> fix them. "What's wrong with 'em?"
> They said "I used a 9V battery to check
> if they were working OK cause the cones
> weren't moving anymore". The cone had
> moved far enough out so the VC was
> mis-aligned. A new surround kit with shims
> fixed one, but the other two were not
> fixable (by me, anyway).

> John A.

Every tweeter I've ever tested for polarity with a 1.5V battery moved enough to be obvious. For the typical 6 Ohm coil of most tweeters, that battery will deliver way less than 1W, low enough to not heat the coil sufficiently.

On the other hand, a 9V battery will be delivering in excess of 10W to that same 6 Ohm, and in the case of the ND20, pushing it to near the thermal limit.

[trevorg]

> Or it would've been my sub, ask Trevor what
> happened. ;)

> NK

Ive done the same thing too Nick