Noob to potentiometers... need some help!

[Infinity!]

Hey guys, as some of you may know, I am completely rebuilding my Infinity RS IIb crossovers. I have everything I need eccept for the last 3 items that I may need to order. The crossover has 3 potentiometers (see attached):

5ohm 5w (2X) (one reading 5 ohms exactly and 1 reading 4.6 ohms)

5ohm 15w (X1) (reading 5.4 ohms)

It doesn't seem to state their tolerance rating, so I dont know what to reference when looking for new ones? Also, where would you guys look to buy replacements? The only place I have found is mouser and all 3 have 20% tolerance ratings which seem quite high: https://www.mouser.com/Passive-Comp...-Rheostats/Potentiometers/_/N-9q0yp?P=1z0x88n

 

[Nixxuz]

From what I can tell, tolerances aren't really hugely important to pots. ALPS doesn't even list it as a spec on their main site.

 

[W9TR]

+/- 20% is pretty typical for a wirewound potentiometer and actually not critical for proper crossover circuit operation.

 

[Infinity!]

From what I can tell, tolerances aren't really hugely important to pots. ALPS doesn't even list it as a spec on their main site.

+/- 20% is pretty typical for a wirewound potentiometer and actually not critical for proper crossover circuit operation.

Oh okay, well that's good to know Last question, if I were to re-use these pots, if you look at the far right one, the middle peg broke off. Why are there 3 different solder tabs/leads?

 

[DaveVoorhis]

Oh okay, well that's good to know Last question, if I were to re-use these pots, if you look at the far right one, the middle peg broke off. Why are there 3 different solder tabs/leads?

A variable resistor consists of a fixed resistor -- the two end terminals -- with a sliding (variable) tap via the middle terminal. If you've lost the middle terminal, unless you have an unusual arrangement of variable resistor, you now no longer have a variable resistor, you have a fixed resistor with a useless knob. There might be a way of fixing the terminal, but it's doubtful.

 

[W9TR]

From, the pic it looks like you can take the metal covers off the back of these and see how they are built. You may be able to salvage the one on the far right as it looks like there is still enough of the center terminal left to solder a wire onto.

 

[Infinity!]

A variable resistor consists of a fixed resistor -- the two end terminals -- with a sliding (variable) tap via the middle terminal. If you've lost the middle terminal, unless you have an unusual arrangement of variable resistor, you now no longer have a variable resistor, you have a fixed resistor with a useless knob. There might be a way of fixing the terminal, but it's doubtful.

From, the pic it looks like you can take the metal covers off the back of these and see how they are built. You may be able to salvage the one on the far right as it looks like there is still enough of the center terminal left to solder a wire onto.

I will definitely see if I can try and fix it. However, do you think it might just be worth buying new ones for 5-6 bucks each? Also, do you guys think the ones I listed on mouser would be a good match?

 

[W9TR]

Yes, looks to be a good match. Hard to justify the time except as a learning experience. These usually don’t fail often unless they are abused so what you already have may be entirely functional.
Tom

 

[Infinity!]

Yes, looks to be a good match. Hard to justify the time except as a learning experience. These usually don’t fail often unless they are abused so what you already have may be entirely functional.
Tom

Thanks Tom! I'll try and fix it in the coming days!