Two of my Mac Plus's showed a lot of flickering when adjusting the brightness. I tried deoxit and it helped, but it didn't completely fix the issue.
It's actually really simple to take apart and cleanup, and I would recommend anyone with a jittery knob to do so. Here's a writeup as I haven't seen anyone show how easy it is to take apart.
No desoldering is required! Use a pair of wire cutters or similar to bend open the four tabs keeping the housing closed.
Clean off the metal contacts on the knob. Use IPA to clean the old grease, then use an exacto knife to scrape off any of the gunk and corrosion build up that doesn't wash off.
On the mounted part to the logic board, clean off the carbon track using IPA. Scape off any gunk on the metal contacts.
Lastly, you'll need to apply fresh grease. Grease allows for smooth rotation and it also protects the alloy from moisture and corrosion in the long run.
I used Super Lube synthetic grease. No need to worry about the grease preventing proper electrical conduction. Their website sites that it can be used as a dielectric grease. Using synthetics will last longer as they will not dry up and become gunky.
After putting the potentiometer back together, be sure to use pliers to close the tabs really tight, otherwise the knob may be a bit too loose.
For reference, it is a 1k ohm linear potentiometer.
Although it's hard to see the real improvement with a video due to the refresh rate flicker, in person issue looks completely fixed without any flicker whatsoever.
Here's a picture of all the components. When I did my first one, I didn't know I didn't have to desolder it from the board.
Before Fix:
After Fix:
It's actually really simple to take apart and cleanup, and I would recommend anyone with a jittery knob to do so. Here's a writeup as I haven't seen anyone show how easy it is to take apart.
No desoldering is required! Use a pair of wire cutters or similar to bend open the four tabs keeping the housing closed.
Clean off the metal contacts on the knob. Use IPA to clean the old grease, then use an exacto knife to scrape off any of the gunk and corrosion build up that doesn't wash off.
On the mounted part to the logic board, clean off the carbon track using IPA. Scape off any gunk on the metal contacts.
Lastly, you'll need to apply fresh grease. Grease allows for smooth rotation and it also protects the alloy from moisture and corrosion in the long run.
I used Super Lube synthetic grease. No need to worry about the grease preventing proper electrical conduction. Their website sites that it can be used as a dielectric grease. Using synthetics will last longer as they will not dry up and become gunky.
After putting the potentiometer back together, be sure to use pliers to close the tabs really tight, otherwise the knob may be a bit too loose.
For reference, it is a 1k ohm linear potentiometer.
Although it's hard to see the real improvement with a video due to the refresh rate flicker, in person issue looks completely fixed without any flicker whatsoever.
Here's a picture of all the components. When I did my first one, I didn't know I didn't have to desolder it from the board.
Before Fix:
After Fix:
Last edited:
