Surgery on Korg Kaoss Pad 3 slider

Distinction

The Korg Kaoss Pad series. Simple stereo audio effectors/samplers/loopers that allow you to control (preset) effects with medium XY touch field.

Made for DJs to control filters, delays, whatever with one finger ( as these are not multi-touch controllers…yet).

I absolutely LOVE these things, and it’s because I’m NOT a DJ. I’m a DRUMMER.

If I want to control sound at the drumset, I have a problem with knobs, because I’m keeping my sticks in my hand.

Like some kind of GAS Pokemon, I feel like I had to collect them all.

kaoss theory.jpg
picture from 2013, when I had two KP1s

For quick comparison, I have

  • one orignal KP1, which has no MIDI clocking, so I use it for filters, reverbs, and it’s distinctively chunky time-stretch.
  • two KP2, which has the most solid construction, MIDI clock sync for some effects, and very quick sampling.
  • one KP3, which has more abundant MIDI sync effects, but has a flimsy-er feeling construction. I do appreciate the 8×8 pixels on the touchpad acting as a crude screen for more UI.
  • one KP4 (“quad”)
  • one Kaossilator Pro (synth and looper), which I sold for more programmable synths (like the QuasiMidi Sirius and Novation circuit).

…none of the battery-powered “mini” KPs, as my drummer-hands need big palm-sided controls.

 

Motivation.

The earlier KPs were surprisingly rugged. My newest unit, the KP3, is certainly more full-featured with more knobs, and a vertical slider (to control Level of the 4 sample/loops), but it’s controls feels wobbly and fragile.

Sure enough, the vertical slider broke off earlier this year.

Now I finally got around to ordering a spare part from Korg resellers Full Compass,

and it’s time to replace it. Given the dense and tight construction of the KP3, this proved a little trickier than expected.

To the Bench

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take off your shoes and screws.

 

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as we can the motherboard has two daughter boards: one thin one for the front-lip knobs and headphone/mic jacks, and the main UI for for the touch-screen.
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seen from the back (port) side, the motherboard connects to the UI TouchScreen board in MANY spots via ribbon multi-cables.

 

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d
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Disconnect the “main” ribbon at “CN1B” first, and it gets easier from there.
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Many of the ribbons use this pull-locking standoff thing. Too big for my Big Dumb Drummer fingers… use small jewlers pliers to (gently) pull the hood loose.

We’re in

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once inside, we can get separate the UI TouchScreen boar from it’s silicon button-interfaces and screen-framing. This allows me to get to the broken slider potentiometer.
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the broken Slide pot, part “VR3” (variable resistor #3). I could use a paperclip to move the part, but it stopped registering as moving, suggesting that the electromechanics are also damaged…

The Heat is On

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solder pads for VR3 looked pretty blobby, so we start at the lowest working temp; 450 for just-at the melting point of (most) solder.
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the pads liquified nicely (perhaps my rework blower runs a bit hot ?)
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out with the old (left) , in with the new (right). AS you can see, the odl unit not only broke the stem of the slide pot (which mounts the knob you grab), but it also cracked the (brown) PCB of the assembly, which is why it didn’t work even when I use a paperclip to move it.
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this large part was a bit hard to steady to solder back in, so I used a bit of bus wire to temporarily lash it in as a 3rd hand.

 

 

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solder pads looks good, and it showed changing resistance when swept.

 

 

Getting OUT !

 

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once re-assembled and turned back on, I see that there is some weird clouding on the numeric screen.
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that “cloud” in the LCD screen proved to be the felt bushing (for the input select switch) had fallen into the screen cavity.

 

Be careful on your way out, folks.  Don’t let the felt switch-busing hit your screen on the way out.

 

 

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the stem of the new slider pokes back through, but feels just as wobbly as when I bought it. THIS is why I defer to the KP2 at the drumkit.

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