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how many Ohms is this potentiometer?

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daviddoria

New Member
i took this pot out of a radio that was having some problems.

upon removing it, i broke it :( the plan was to test it with a multimeter or something to see the range... it is only the volume knob...so i figure i can use a nonvariable resistor in its place just to see if the radio works...

here is what's on the pot...
S* 178B9498-4 d
note!: when i put "*" it was really a circle/yingyang looking symbol, at first thought i thought it was a zero, but i dont think it is

i looked up that number online but didn't get any results

any suggestions on where to find out what this is?

david
 

Kingpin094

New Member
What broke?

What part of the pot. is broken? If it is a volume control out of a radio it is probally in the 10k to 50k range. What type of radio did this pot. come out of?
 

kinjalgp

Active Member
If I am not mistaken the "S" should be "5" and the circle like symbol you are talking about is "OMEGA" that is the unit of resistance (Ohms). So the pot is most probably of 5 kilo-Ohms.
 

daviddoria

New Member
haha kinjalgp. indeed this symbol is not omega. it infact looks extremely similar to a zero, but the line through the zero is squigly, thats all that concerned me.

is it normal for there not to be any sort of other markings on these things?

kingpin: it came out of a GE radio, a little clock radio.

so if i get a nonvariable resistor i would put it from where the 2 outside pins of the pot were correct.

ex.
old pot:
| | |
o o o
new resistor
------\/\/\/\/____
o o o

or do i need something in the middle hole?

david
 

bogdanfirst

New Member
i think the pot might be a 10k one, usually in the radios, this is what it is used.
if u plan in using a resisotor then the signal in and signal out should be connected together and then connected with the resistor to the ground.
probebly the middle pin is the OUT and one of the pins from the edge is the ground and the other is the signal in
like you say
1 2 3
| | | />max
o o o /
------->
if you get more volume when you turn the pot counterclockwise then u need to connect cogether 2 & 3 & the resistor and the othe pin of the resistor wound be connected to 1 wich should be the ground.(1,2&3 are the pins) try more resistor values....
and can u send a picture of the pot.
usually when you unscrew the knob u would find the value there, near the place where the screw comes, somathing like 10K, 25K etc.
 

daviddoria

New Member
ahh cool, so the middle pin is out. thanks

also, i stuck a 25k pot in there and it worked like a charm.

just 1 slight problem though, when i touch the metal rod of the pot with my finger, it gets a lot of static. i know you can't touch caps with conductive stuff, but apparently it is true for resistors as well?
 

Sebi

Active Member
When the poti have metal rod,also have a pin for GND. Just make a shorctcut to poti GND pin.
 

herbymcduff

New Member
Sebi said:
Whe the poti have metal rod,also have a pin for GND. Just just make a shorctcut to poti GND pin.
What you are saying is that the potentiometers that have metal rods, also have a pin for GND. So you want to make sure that you have that pin secured to ground.

Also on the static noise, check for loose connections around the potentiometer.
 

bogdanfirst

New Member
so you say ythat after you replaced the pot with the resistor and you tuched a pin from the resistor you get noise...wel that would be normal, because aoudio signal is going trough there and if you tuch it with something metal you would get noise...and if the metal object is not insulated an you hold it you would get even more noise
 

Mat

New Member
:D lLog/linear potentiometers, why if the resistive track is not broken can't it be measured with a meter on ohms range connected across the resistive contacts that would give the unknown value.
 
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