Volume problems on PT-30 ?

[logan97]

Hi! I just bought a Casio PT-30, and I really love it, except that the volume slider doesn't work properly. At maximum volume, it is very loud, but if I set it even slightly lower, it's barely audible. The listing made no mention of this defect, so I'm a bit unhappy, but I'd like to fix it if possible. Can it be fixed without causing further damage? I don't really know anything about modifying electronics, so I'd prefer a simple solution if possible, or maybe there's some kind of store that could fix it for me? If not, my next step is going to be taping some cardboard or fabric over the speaker so I can play at max without blowing my ears out, haha. Thanks in advance!

[Chas]

Almost certainly some wear, oxidized or corroded contacts in the volume slider potentiometer. 

 

You could try getting some switch cleaner and squirting it into the slider, though ideally it should be taken apart and cleaned for a lasting and effective repair. 

 

Switch cleaner is cheap, quick and might get you instant results. Remove the slider cap, squirt a small amount inside the slider (the gap where the volume post slides), work the post back and forth and see if that helps.

[CYBERYOGI =CO=Windler]

Never ever use "switch cleaner"/"contact cleaner" on potentiometers. Particularly with such old slide pots (happens regularly in Bontempi) they will dissolve the carbon track into black goo and so destroy the potentiometer. It is safer to dismantle the whole thing (but be extremely careful with the brittle LCD foil cable) and take the pots apart for cleaning.

 

I already had successfully poured isopropanol into Casio potentiometers for cleaning (in MT-70 which is hard to access) but particularly with 1980th sliders this is unsafe. Try to play some decathlon (quickly move the pot 20 times back and forward) to clean it.

 

Of the carbon track is worn, you may dismantle it and fix it with conductive silver or carbon paint, but that's fiddly work and you need to fully dry the paint (by hairdryer or time) else it will scrape off by any move of the slider. Another primitive fix is to re-coat the carbon track by painting it black with a soft pencil, which graphite is similar but not very robust either. Use a DMM to verify the Ohm velue. (You rarely get closer than about 2/3 to what it should.)

Edited June 9, 2022 by CYBERYOGI =CO=Windler