can a volume pot be restored?

[Rodrigo mtz]

i own a Gradiente model 80, it has been with me since new in around 72-75, but lately its been having this problem with the volume pots were sometimes i wont get any sound at all, and sudenly without touching the knob it will go intoo full volume, in other times it will just refuse to do anything at all

 

[redk9258]

This would probably be a good start...
https://audiokarma.org/forums/index.php?threads/the-idiots-guide-to-using-deoxit-revisited.207005/

 

[elnaldo]

some fails can be repaired opening the potentiometer. Sometimes a broken contact between the metal tabs and the carbon trace can be restored with conductive paint.

But check if cleaning from the outside is enough or if the solder is OK at the PCB.

Full volume means the potentiometer has lost the connection to ground. No volume means it's not passing signal (input pin or output pin disconnected), or the output (mid pin) is connected to ground.

 

[northpaw]

A dirty or failing speaker relay (if your unit has one) can produce those symptoms as well. Tapping gently on the relay case while music is playing can reveal if the sensitivity is localized there.