Author Topic: How to replace a potentiometer in a speaker - if that is what the problem is?  (Read 1198 times)

0 Members and 1 Guest are viewing this topic.

Offline optonox

  • Contributor
  • Posts: 6
  • Country: us
Hi,
I have an issue with some speakers that were covered by a youtube video from the EEV Blog.
Specifically the KRK Rokit 6s repaired in this video


I have a separate problem though.  For some reason one of my pair will not put out sound (or puts out very low sound) unless I forcibly wiggle the volume knob on the back.
I took off the back cover and can see the pot - (it is visible in the part of the video I linked to) but it seems light a nightmare to replace it.

In your experiences, is something like that (volume very low) a bad pot?   It is definitely soldered correctly but I have isolated the problems to that part of the speaker.  Wiggling it or forcing it all the way to the max and still twisting makes it temporarily work so I do think it is what is to blame.

However, if it *is* the problem - how do I fix it.  It is wedged so tightly that I would have to remove parts that are glued on to access the solder...

They sell replacement pots here  https://www.fullcompass.com/prod/233428-krk-potk00015-rokit-8-volume-pot?gclid=CjwKCAiAlb_fBRBHEiwAzMeEdjzwN8UjAh47ZpFnHkNAHSd0haJ__gIlvymgeSPXyPz7sngLWlYhMhoC6mYQAvD_BwE so I must not be the only one who has had this problem.
 

Offline helius

  • Super Contributor
  • ***
  • Posts: 2950
  • Country: us
If you haven't removed the rubber cap from the potentiometer, you can safely do so. If there isn't any grub screw holding the cap to the shaft it's almost always simply press fitted. At that point, you can see if there's a panel fixing nut. By loosening the nut, the potentiometer will be free and you can pull it out from the inside of the case.
 

Offline Whales

  • Frequent Contributor
  • **
  • Posts: 984
  • Country: au
    • Halestrom
Do you get scratchy noises when you rotate this pot?  It could just be dirty. 

If you don't have contact cleaner handy: standard rubbing alcohol/metho does a good job.

Offline optonox

  • Contributor
  • Posts: 6
  • Country: us
helius: looking at this image - what is the panel fixing nut that I loosen?
Are you telling me there is a way to remove the pot without de-soldering it?

Whales: Not really scratchy noises, it just does not work til I rotate it a certain way.
 

Offline helius

  • Super Contributor
  • ***
  • Posts: 2950
  • Country: us
OK, I just went ahead and assumed it was a panel-mounted pot, but it looks like it is soldered directly to the PCB, so you would need to remove the PCB before desoldering anything. That means loosening the nuts on both pots and breaking the silastic that holds the board down and on the ribbon cable.

helius: looking at this image - what is the panel fixing nut that I loosen?
It's the hexagonal flat nut near the top of the image. It clamps the body of the pot to the panel, and is hidden by the knob that slides over the splined shaft at the top of the image.
« Last Edit: November 18, 2018, 04:17:16 pm by helius »
 

Offline optonox

  • Contributor
  • Posts: 6
  • Country: us
OK, I just went ahead and assumed it was a panel-mounted pot, but it looks like it is soldered directly to the PCB, so you would need to remove the PCB before desoldering anything.

Is it possible to repair this without desoldering the pot?  Like remove part of the pot as laid out here https://www.ifixit.com/Guide/How+to+repair+a+broken+potentiometer+or+pot/67387
 

Offline helius

  • Super Contributor
  • ***
  • Posts: 2950
  • Country: us
People try to "fix" potentiometers by spraying them with Deoxit, but all that can do is dissolve dirt or dried grease that's interfering with the wiper. If the track is physically worn out, it simply needs to be replaced. There is not another way to repair a potentiometer.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf