Replacing volume pot in a hi-fi amp

diggy_dude

diggy_dude

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I have a Technics SU-V3 that's in great condition other than a busted volume pot. I have my eye on a Noble replacement pot that is of the correct resistance (100 kOhms). How can I tell if it will physically fit the PCB pinout of the original pot? Are the dimensions fairly standardized?
 
The case diameter appears to be about the same too (15 or 16mm). Is that a good indication that it will fit?
 
I've had success installing a PCB board pot "from" maker A in gear from maker B, so from my experience, they are standard. But maybe they all are not.
 
Thanks, Stevie. I went ahead and ordered the pot. It's not likely the pinouts could be radically different.
 
I guess in the worst case, you could attach the pot with short leads. You should be able to locate a datasheet for your new pot, which would indicate the physical dimensions.

Paul
 
I wouldn't know where to look for a datasheet. I Googled the number printed on the pot in the photo and it turned up nothing.
 
Who is supplying the pot? Potentiometer, that is! Places like Digikey or Mouser usually have the datasheet available from their site. There's a good chance it will fit directly if it looks similar or identical to the original. More important to have the same value and taper. Paul
 
It's from an Ebay seller in Hong Kong. It has the same value. I would assume since it's a volume pot it would have the same taper. It's not terribly expensive, so I'm just gonna get it and see if it fits.
 
The dimensions are not included in the description? Try contacting the eBay seller for some or the datasheet.
 
The case diameter (16mm) was in the description. I already bought it, so I'll find out when it arrives.

I have a replacement aluminum knob with plastic insert from another old Technics amp. The hole where it mounts on the pot shaft has a flat side. The pot shaft is round with gear teeth. It's gonna be fun trying to get the knob on without breaking the plastic.
 
You probably will break the plastic. At a pinch you might be able to carefully drill out the hole. You mention that the new pot has a splined shaft (that's the ridging), so you could either try to locate a press-on knob that will fit on the splines, or get a knob to fit a round shaft, and which has a small screw in the side to tighten it on the shaft. You will find these easily at any "serious" electronic shop (where they sell components like resistors and stuff), or even try your ebay seller.
 
I have the original aluminum knob with destroyed plastic insert. Unknown to me, a previous owner had super glued the knob onto the shaft. It was lopsided when it dried, and rubbed against the hole in the aluminum faceplate. I tried to pull the knob off not knowing it was super glued and broke the pot.

My idea is to remove the plastic from inside the aluminum and press some plastic modeling compound (e.g., Feemo) down in there. Then press it onto the shaft to make an impression of the splines, then bake the knob at low temperature till the plastic hardens.
 
When I've had to buy new pots in the past I do my best to bring the old one with me and find it in a store somewhere so that I can physically compare the old to new. I reserve buying these kinds of things over the net as a last resort.
 
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