Repairing the balance slider

The malfunctioning pot, is the second one from the left on the picture.
Looking trough the openings of the pot I already could see there was something wrong. Only one half of the slider had a moving copper contact. At the other side the copper contact had come loose, and was forced and deformed, pushed to the end of the space in the slider.

The pots are mounted with melted plastic to the board.

With a screwdriver I broke the plastic away so I could take out the pot, and I unsoldered the connections.

The pot is closed with small copper rivets. I decided to drill out these rivets in order to open up the pot.

Opening the pot showed me that the pins on the white plastic slider had broke off. These pins should hold the copper contacts. One of the copper moving contacts was deformed but this could be repaired by use of pliers.

No, this blog is not sponsored by Pattex. This is the glue I used to glue pins into the white plastic slider.

I drilled holes on the spot where the pins used to be. In the holes I could stick new pins and glue them in. For the pins I used two stiff wires. Ordinary wire you use in electronic projects.

The new pins now can hold the copper contacts again.

A view of the opened slider. The inside was sticky, so I cleaned the internals with isopropylalcohol. I only cleaned the upper resistance counterfoil, not the graphite counterfoil below. I did not want to take the risk the graphite would solve into the isopropylalcolhol.

Remounting the slider was not easy, and had to be done very carefull. I closed it up with thin copper wire, just in case I ever have to open it up again.

Then I glued the slider back in with Tec 7.

Now the balance slider is working again perfectly without any crackling.