Sherline motor problem

[panofish]

potentiometers are susceptible to oxidation/corrosion which can alter their resistance without being touched. Age, humidity, quality and other conditions can affect this. The best solution is to replace, but you may get many more years out of a pot simply by rapidly swiping it back and forth several times. This can scrub off the oxidation/corrosion... etc and bring a pot back to life.

 

[lensman57]

Late to the party, I know.

Trim pots generally do not turn by themselves so the question is: Why did it? Or why did it change in value? In either case, you might continue the hunt for a replacement pot to have on hand if this one does fail completely.

If unable to find something (should it be necessary) you can always check the other four pots to see if they are of the same value and taper. If so, measure the resistance they are set to, replace them with resistors of equivalent value, then use that pot as the replacement. Guess you could do that for any of the pots, if they fail.

Hi,

Thanks for the reply, i have already ordered a replacement pot and even tried to get a spare control box but with no success, if it goes funny again I will replce the pot for sure.

A.G

 

[Don1966]

Glad to see you have it under control. Panofish has it correctly, humidity plays a toll on the components and do affect them without touching them. The trimmer is made on a ceramic surface with resistive material and a film can build up to change is value. This does not mean it is about to fail, like Panofish says rotating it back and fourth generally clears it up.

Have a good Day
Don