On 2025Nov 2,, at 11:15 AM, Rob Jarratt via cctalk <[email protected]> wrote: > > I have the contrast control on the monitor of my Olivetti M24 which has > become unreliable, you only need to touch it and the display will disappear > completely. It doesn't look too hard to replace the rotary potentiometer, > but I was wondering if there is any way to "repair" it to keep the original > part. It looks like this: > https://1drv.ms/i/c/fc758a5a91b91301/ESPGlbvW5wxGpXPC5kXfzVMBTUUW96GThzDMqZ_ > i8jq7tA?e=Ehmo1T
It looks like the wiper and resistive-element are exposed and somewhat accessible. - I would start by dripping some iso-prop or other contact cleaner on the R-element and rotating. - If inadequate, cut a tab of stiffish paper, insert it onto the R-element surface, rotate the wiper onto the paper, soak it with IP/contact cleaner, rotate back and forth on the paper, and/or, try sliding the paper back and forth while it’s in between the wiper and R-element. - There will be a 2nd rotating-contact metal-to-metal interface between the wiper and the center pin somewhere towards the interior. - Check if any of the crimp or rivet connections for the 3 solder-tabs are loose. Sometimes they can be (carefully) recrimped a bit, but try to crimp on the sides of the U not at the curve. I avoid spraying contact cleaners with oil in it. As spray, the oil deposition is uncontrolled and ends up everywhere - if not on immediate application, eventually it spreads across surfaces to everywhere. If oil is needed such as in the throat or on moving surfaces, I apply it manually by tiny drop(s) from the end of a tiny screwdriver or somesuch.
