# inside of a Curtis 5k pot



## otp57 (Feb 7, 2012)

otp57 said:


> Do any of you have a photo of the inside of a Curtis 5k pot?
> I would like to see the inside of one.


Ok guys can anyone tell if a Curtis pot turns 270 degs when out of the potbox or is it 90 Degs. I know the pot bot has stop to keep it from turning more than 45 degs.


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## frodus (Apr 12, 2008)

neither, it's 40 degrees

http://www.tecknowledgey.com/curtis.../curtis-98191-potentiometer-0-to-5k-ohms.html


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## major (Apr 4, 2008)

frodus said:


> neither, it's 40 degrees
> 
> http://www.tecknowledgey.com/curtis.../curtis-98191-potentiometer-0-to-5k-ohms.html


Hey frod,

I've had to replace a few of these pots over the years. I had one or two failed units I tore apart. I see the housing for one here but can't find the guts.* Anyway, it looks like a regular pot inside and will twist the full 270 or 300 degrees. But the resistive element on which the wiper travels is different. You can plainly see where only a section is "resistive" and the remainder is just conductive.

And I just laid a protractor on a PB-6. The travel stop to stop is 60 degrees. The "box" does the travel limitations, not the pot. I have many times adjusted the arm clamp to get this travel in synch with the active region of the pot.

Even though the box may limit the travel to 60 degrees, the actual active region in the pot itself may be 40 degrees as per that spec sheet. You could have 10 degrees of zero ohms and 10 degrees of 5K.

major

*edit* I just found one in a box under the desk. See, I'm not crazy---well maybe somewhat. I'll see if I can get a photo of it tonight.


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## frodus (Apr 12, 2008)

Thanks for the tip!

So if you modified the potbox and got a 45degree resistive pot (or hall effect if your controller supports it), that would work as a replacement.


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## major (Apr 4, 2008)

otp57 said:


> Do any of you have a photo of the inside of a Curtis 5k pot?
> I would like to see the inside of one.


Likely some poor photos. I am no photographer 










You can see the resistive portion of the element opposite from the 3 solder terminals. The rest of the element is just conductive.

Hope that helps,

major


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## otp57 (Feb 7, 2012)

major said:


> likely some poor photos. I am no photographer
> 
> 
> 
> ...


thanks for your help:d:d:d:d:d


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## otp57 (Feb 7, 2012)

otp57 said:


> thanks for your help:d:d:d:d:d


cAN YOU DO A CLOSE UP OF THE INSDE OF THE POT THANKS


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## major (Apr 4, 2008)

otp57 said:


> cAN YOU DO A CLOSE UP OF THE INSDE OF THE POT THANKS





major said:


> I am no photographer


That's as good as I can do. Closer turns out blurry


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## otp57 (Feb 7, 2012)

major said:


> That's as good as I can do. Closer turns out blurry


Thanks I will use a program to blow it up thanks
I think a 20K to 30K lin. pot will work using 45 to 50 deg of the pot range.


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## otp57 (Feb 7, 2012)

frodus said:


> neither, it's 40 degrees
> 
> http://www.tecknowledgey.com/curtis.../curtis-98191-potentiometer-0-to-5k-ohms.html


Thanks that was one of the missing pieces that I need to know THANKS


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## piotrsko (Dec 9, 2007)

a 15K ohm pot 270 degree linear taper is 5K at 0 to 90 degrees.

270 / 60 = 4.5 so for 60 degrees you need 22.5 K pot linear taper rounded to 25 K.


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## otp57 (Feb 7, 2012)

piotrsko said:


> a 15K ohm pot 270 degree linear taper is 5K at 0 to 90 degrees.
> 
> 270 / 60 = 4.5 so for 60 degrees you need 22.5 K pot linear taper rounded to 25 K.


 I am playing with a 25k liner and will try a 30k


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## Zappo (Sep 1, 2011)

piotrsko said:


> a 15K ohm pot 270 degree linear taper is 5K at 0 to 90 degrees.
> 
> 270 / 60 = 4.5 so for 60 degrees you need 22.5 K pot linear taper rounded to 25 K.


That is exactly how one of my cheaper pot boxes is made. It is a 15k pot and the box has hard stops limiting it to 90 degrees of travel. It works okay but I've decided to go to a HEPA input instead.


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