Obliq Museum – Elektron Octatrack Repair

I’ve recently been really getting into the Elektron Octatrack sampler/looper.  My band partner Jeff of Multicast came down the other night and we had a very productive session.  But, I spilled a little bit of cider on the top of it and some got down into the unit before I could completely dry it off.

I turned it off for a while and a later when turning it back on most things worked, except for one pot and the crossfader.  Bummer.  Too much clutter in the studio and lack of discipline!  I took the unit apart tonight with the goal of cleaning everything with q-tips and isopropyl alcohol and hoping for the best.

Octatrack goddess

The octatrack goddess – the voice in the machine!

Taking the Octatrack apart is pretty simple.  Some 2mm hex screws on the outside, and the User Interface PCB is a Torx 10.  I wanted to take it completely apart so i could ensure that I got everything that seeped into the unit clean.

CPU and Power Supply

The CPU Board and Power Supply are attached to the bottom case

Upon taking it apart, I could see where the bottom CPU board needed a little cleaning and so did the bottom of the metal case enclosure.  Nothing too bad, which was great to see.

Octatrack user interface pcb

User Interface PCB detached from the front face plate

The main user interface PCB looked pretty good too.  I cleaned around the pots and otherwise there really was no staining or remnants of the mishap.  Since Pot B wasn’t working, I cleaned all around that area including the pot itself.

Octatrack Cross Fader

Cross Fader assembly and PCB

The cross fader was interesting, much more mechanical than I would have guessed.  A nice design to take a beating without breaking.  You can see the PCB pulled from the rest of the assembly.  The digital design would slide between the two “tents” on the PCB and IR light would reflect and get caught by the sensors.  Everything was done by light, neat.  This assembly needed some cleaning as the metal shafts were a bit sticky. The cross fader is an Infinium 45mm Crossfader DX400211.

Octatrack cross fader

Octatrack cross fader

Taking apart the cross fader (my warranty period expired a couple of years back) I noticed something making a sound, like a really small loose screw.  I popped off these plastic covers showing the IR LED and light sensors and noticed that PT8 has a small piece of glass (?) that fell off.  This is super small and i won’t be able to fix it.

Cover for the IR LED and holes the sensors read the light through the encoded pain on the plastic (next photo)

Cover for the IR LED and holes the sensors read the light through the encoded pain on the plastic (next photo)

If you note in the above picture, there are 7 holes which allow the IR LED (bottom center) to reflect off of the “tents” and be ready by the sensors underneath.  I presume that the reason for the plastic piece is to control the exact amount of light that each sensor can receive.  I noted that a couple of these were covered by the cider, so I cleaned these up really nice.

Encoded paint with the IR  light interacts with to allow the sensors to read where the fader is at.

Encoded paint with the IR light interacts with to allow the sensors to read where the fader is at.

Upon putting everything back together, the pot worked great, and the fader worked all but 5% of the extreme left in which it centers.  I’m going to try and get a replacement from Elektron, but in the mean time I’m going to tape something to stop the fader from going all the way to the left, and that should be a work-around to the issue.

What is It's A Boo???

What is It’s A Boo(?) mean ?

Upon putting everything back together, all functions except for the extreme left on the fader are working flawlessly now.  I put in an email to Elektron asking for the replacement cross-fader part.  If it is cheap, i’ll buy two and have a spare.  Happy that not much damage occurred to the unit; I could probably play using it without any change now; but I do want to fix the cross-fader if I can; meanwhile I’ll use the work-around.

Loop User Interface

Loop User Interface

Obliq Service Center – Elektron Repair

Elektron Repair Session!  Nathan and Jahnavi stopped by and we replaced broken potentiometers on our Elektron MachineDrums and MonoMachines! It was a great evening when we got everything working again!

Here are the basic repair instructions that inspired us to do this ourselves…although we found there wasn’t much of a need to take apart the encoders if you get all the solder with a good solder sucker and wick.





Check out Nate & Jahnavi’s photos of the session!

Sequential Circuits Pro One – Alive after 20 years!

It is time, finally, to repair my Sequential Circuits Pro One synthesizer!  Back in “the day” when I was picking up analog gear like it was trash to the new “digital synth craze” I was able to procure this for $35 (it was DOA). I have purchased 2 CPU chips over the years but they were DOA as well. Finally, I ran across this new Turbo-CPU chip from Music Technologies Group. I have yet to install the MIDI part, but the SCI is working like new!

What a great piece of gear; I HIGHLY recommend MTG and appreciate his passion for keeping old synths alive!

Getting ready to replace the chip:

Before/After of the CPU:

The Pro One after it was 100% working!!!

Some cool etchings on the board! Anyone know what the bottom one says?

Here is a quick drone track I did immediately after it was working. The first time this machine has talked in at least 20 years!
Sequentialstein by davealex