Obsoletetechnology Music, Electronics and Repairs

Page and personal logbook about electronic music, vintage music electronics, DiY, repairs and midi stuff.

For Obsoletetechnology Music, visit the Obsoletetechnology Soundcloud  and Bandcamp page.


New record release:

Added: Siemens U273b Limiter repair

U273b Front View

Added: Siemens W295b EQ repair

W295b Front View

Added: WSW 601433 Limiter repair

Limiter opened up

Added: Ursa Major Space Station Recapping

Inside SST282

Finally fixed my PPG1002 synthesizer! (January 2018)


I started a bandcamp page with the intent of releasing my entire musical backlog, starting from 2004 onward. All downloads will be free of charge.
The first couple of releases will be live recordings performed on stage in Kulturfabrik Esch-Alzette under my aka ‘Veste’.

Added a page about the repair of a Ursa Major Space Station SST282: (November 2017)


Added a page about reading out the PROM memory ic’s of an Ursa Major Space Station SST282: (November 2017)

New Obsoletetechnology mixtape on Soundcloud: (October 2017)

A selection of tunes for September.

Added Bang&Olufsen Beovox 80.2 Speaker Re-Foaming: (October 2017)

BEOVOX S80.2 Foam Edge Replacement


Added Univox Mini-Korg power supply repair: (July 2017)

Univox Mini-Korg 700 MK2

Added Pro-Ject DebutIII repair: (January 2017)

Pro-Ject DebutIII Turntable Repair

Pro-Ject Speed Box PCB

True Bypass Module (October 2015):

4 Channel true bypass module
4 Channel true bypass module

This is a simple relay based true bypass module for 4 channels of audio. It has been designed to handle 4 balanced audio channels, which means that it could also be used as an 4 channel unbalanced stereo bypass switch.

Midi Filter Tool (December 2014):

PCB fully assembled
PCB fully assembled

This device allows the filtering of midi messages on the midi bus. The unit provides a wide variety of configurations while only requiring a very basic user interface.

The unit is designed as a low cost/low part count device targeted at diy-building and is based on a pic16f1829 microcontroller running at 32Mhz.

Utilization examples:

  • Pass only midi note on/off events.
  • Let midi sync only through on one single channel.
  • Remove everything except CC messages.
  • Parse Program Change messages.

Record release on ROHS! Records: (03 February 2014)

A new Obsoletetechnology mini-album ‘Radiant’ now available on pre-order from ROHS! Records:

Edition of 50 limited hand-numbered printed CD-rs. All copies comes in a plastic clam shell cases.Includes immediate download of 5-track album in the high-quality format of your choice (MP3, FLAC, and more), plus unlimited mobile access using the free Bandcamp listening app.

Shipping out on or around 25 February 2014 http://rohsrecords.bandcamp.com/album/rohs-007-cd-obsoletetechnology-radiant

New Project Added: (01 January 2014)

CV-Gate To Midi Converter

Low cost CV-Gate to Midi converter allowing to convert analog CV-Gate and CV signals into Midi Note On/Off and Midi CC messages.

CV/Gate to Midi Prototype Wiring (Front)
CV/Gate to Midi Prototype Wiring (Front)


Newly fixed:(16 April 2013)

Sequential Circuits Prophet VS

SCI Prophet VS Frontpanel
SCI Prophet VS Frontpanel

Added 2 more repairs: (25 March 2013)

Elka Synthex Fan replacement

Power Supply with new Fan
Power Supply with new Fan

Roland VP330 Vocoder Compressor circuit

VP330 Frontpanel
VP330 Frontpanel

New EP released on Gotwax!

The second gotwax! EP is a slamming longsided club two-tracker with detroit- and dub-flavoured raw-body-music. The future as it used to be!

Gotwax! 002 – Obosoletetechnology
Sleeve Front

Preview Tracks:

New repair added for a Yamaha CS5 Synthesizer (11/11/2012)

Yamaha C5 Frontpanel #2
Yamaha C5 Frontpanel #2


Lately repaired: (11/05/2012)

Juno-106 Synthesizer

VCF-VCA replacement due on two voices.

Roland Juno-106 Buttons
Roland Juno-106


New project added: (07/01/2012)

Midi to Trigger Interface

This Midi to Trigger interface generates a TTL (5V) trigger signal per note over a range of ten notes. It can be used for example as a midi interface for vintage drum-expanders or as a multiple-trigger generator for a modular synthesizer.


New project added: (04/01/2012)

Tama TS305 Midi Trigger Modification

The Tama TS305 drum-expander, which is a great sounding machine but unfortunately totally lacking of midi control.


Newly fixed: (19 nov/2011)

TR-808 Handclap circuit repair/BA662 replacement

TR-808 not working
TR-808 needing repair.


TR-606 power supply repair and switch replacement.

TR-606 working again
TR-606: Repair done.


New project added:(01 nov/2011)

DC-DC converter based bipolar power supply for effect units and portable devices.

Some circuits require a bipolar power supply. In a portable unit like an effect pedal, that can sometimes be troublesome, since it is likely that we want to power our effects with a standard 9V or 12V wall-wart or batteries and don’t like the idea of putting an AC mains transformer plus rectifiers and filtering into our boxes. That’s where a Dc-Dc converter based circuit can be an alternative:

Power supply for effect units
DC-DC converter based bipolar power supply


Project Updated: (01/10/2011)

New firmware version for the Midi-CV/Gate converter. The new firmware allows CC Controller assignement and individual CC Midi channel selection.

See updated project here.

Midi to CV Gate Interface
Midi CV/Gate converter


Lately repaired:


Another TR-909 for repair on the Bench. This is actually the 4th TR-909 I am repairing! It came with a problem on the bass drum ‘Attack’ parameter, turning the knob wouldn’t do anything. I thought this would be an easy one and a good cleaning of the potentiometer would cure the problem but not so…

TR-909 PCB
TR-909 Inside

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