Hi!
The knobs of my Korg Monologue became sticky and disgusting to use.
Any of you have good advise about knob replacement or original knob cleaning methods?
Would like to hear suggestions from other Monologue / Minilogue users that experienced the same knob degradation.
Thanks!
I have one synth of many which typically have this, but only one which was not in heavy rotation … anyway, the microbrute has this stuff on it, probably some of the worst based on user fbk
i hunted down advice elsewhere and found that diluted baking soda in a light paste rubbed in with a toothbrush worked a treat
it took a while due to its facets, so i didn’t do them all, time permitting one day i will
i was impressed with the outcome, they are simply shinier without that texture, but it looks and feels better and could pass as a new 90s era product
Obvs you need to test any process by starting gently with as dilute a preparation you can, testing on a hidden area if poss/appt - do teh research, but the baking soda was just the ticket for my case
ps there’s a whole topic on this somewhere - search sticky mess TPE or something along those lines
Also got a Monologue that’s developed this issue. Definitely wasn’t from overuse.
Thanks for the tip @avantronica.
My Matrixbrute going the same way with identical knobs as the Microbrute. I’ll try that method.
Report back if you can streamline the laborious process before I resume tackling my easier task with the micro … its wheels will not be so much fun
you can also remove the knob caps, place them in a container, and then fill the container with 91% isopropyl alcohol to cover the knob caps. Let them sit in the alcohol until you see the sticky coating lifting off, took about an hour for mine. Then, clean the residue off of each knob cap with a toothbrush. You may have to do this process twice to remove all traces of the coating.
I’ve had to do this with a couple pieces of gear, but it’s totally worth doing, it solves the problem permanently.
WARNING: Keep isopropyl alcohol away from the front panel of your synth! Most will be fine, but I damaged the finish slightly in one spot on my Minibrute by cleaning it with alcohol (purchased a used one)… If you need to clean the front panel, use a damp cloth - and if it’s really dirty and you have to use a cleaning solvent like alcohol, test an inconspicuous spot on the synth first, before wiping it all down with alcohol.
Curiously, I also have a Minibrute SE whose knobs also have a somewhat sticky feel and are not at all pleasant. Maybe you should buy 91% isopropyl alcohol to do this process with the knobs of both synthesizers. Is only 1 hour enough to remove the rubber layer?
Thanks for the advice!
I found that it didn’t take long for the sticky coating to start to dissolve, I could see that it was working about twenty minutes into the process - the outer layer got cloudy and started to lift away from the edges of the knob caps… I waited a full hour to make sure the coating would come off, but I think I could have left the knob caps soaking in alcohol indefinitely, the underlying hard plastic isn’t harmed at all by the alcohol.
Edited to say: I dread the day I have to do this with my mkII elektrons!! I’ll have all blank buttons 
but I already know that coating will get gross over time…
Science question here:
Browsing on Amazon i can’t find (at least in Amazon Spain) 91% isopropyl alcohol but I find lots of brands with 99,9% percentages.
Is there any difference on using 99,9% formula in this specific use we’re talking here?
Sorry, I failed at chemical classes back at school years.
The higher the perecentage, the more betterer it is.
You can safely use 99.9% alcohol, Microtribe is right - a higher percentage should dissolve the coating faster.
I’m in the US, and 91% is a concentration that can be easily purchased here (I can find 99.9%, but it’s more expensive and I have to go to a specialty electronics store to get it).
My solution:
Maybe not a streamlined method, but I happenstanced upon an old box of hospital 70% isopropyl prep pads and decided to tackle the Monologue, as well as 3 Keystep knobs which are exactly the same as the Matrixbrute. Maybe 45 mins of work to succesfully remove the gunk (as well as add some Posca white marker lines to the Monologue knobs). Definitely worth doing rather than adding more plastic to landfill. I’ll try the baking soda method once the studio is unpacked on the Matrixbrute, as well as an Akai Force going the same way.
Update: I tried the 99% isopropyl alcohol method but I ended up with my knobs looking like this:
I put them 1 hour into a glass with isopropyl alcohol, and then let them dry.
Later I grab a microfiber cloth, put some gloves in my hands (this alcohol damage your skin) and rubbed them with more isopropyl alcohol. When still wet they look great, but then a few seconds later when dry they look like in the photo.
They’re not sticky anymore, but they look awful! Do I have to rub them again with some old cotton t-shirt or a microfiber cloth? I am not too picky with how the knobs look but… damm it!
Timely stuff, as I recently discovered my Beatstep knobs had gone down the same sticky path. They’re now looking similarly dusty, like Fields of the Nephilim have borrowed the Beatstep to do a quick remix, but in my case they’re also still sticky. Hooray! I’m going to try the baking soda tactic just for fun, as I expect the Beatstep’s main hope lies in me picking up some new caps. This is some real Vance Packard business going on here. In an ideal world all our favourite synth YouTubers would get together and launch an investigation.
Have had this happen to so many pieces of gear. I find that no amount of soaking or cleaning will ever get them perfect. My go to method is soaking in 91% alcohol overnight, quick rub down in the morning then giving them a couple of coats of spray paint. For my Monologue I ended up going with matte green because it’s what I had on hand. Put in the extra effort to paint the indicators orange.
