Bad pot

Well, not the kind you smoke anyway. (And that's Potentiometer to LV to be politically grammatically correct). Just ran across a powered sub woofer that was dead. Nothing seemed fried. Further tests showed no continuity off the volume control. Pretty standard cheap dual gang 50K control. Took it off expecting to see a cracked board. The board was not cracked on either section. Thought this was quite strange. I fluked across the carbon and it was OK. What seems to have happened in this unit was where the carbon track gets riveted to the terminal developed a open circuit condition. I have never seen one do that before. And it happened on both sections. on more than one unit. Definitely a cheap pot with a latent manufacturing defect. I have seen similar pots in pro sound gear, so be on the look out. Its says "HV A50K" on this specimen.

Bob

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Reply to
BOB URZ
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Just run us through the model subs you were using, makes it alot easier.

Rob

Reply to
Rob Beech

These subs were KLH, not pro units. But the pots are similar to what found in many lower end pro devices. Its not the point of what they were in, but the method of failure. With so many companies building cheaper stuff in the pacific rim, this sort of thing is bound to crop up more often.

Bob

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Reply to
Bob Urz

Yep, definitely seen that before. I used to do consumer electronic (stereo) repair, back when the stuff was actually repairable. I have only seen it on very inexpensive pots. I would not have expected to see that crap in pro audio gear ten years ago. But today ... it's everywhere. Mike T.

Reply to
Mike T.

I've got an NHT hifi amplifier sitting around that had this happen on the ground end of the pot. So when you wiggle it it goes to near full volume regardless of the rotation. Most annoying, and I haven't worked hard enough to find a source for a dual volume control with small shaft.

BH

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Reply to
BillHart,KarenPierce

Sucks Don't it, I see it all the time, My last one was a trimmer, I noticed a circuit that was intermittnetly noisy and tracked it down to the same thing on a trimmer!!!

Chad

Reply to
Chad Wahls

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