The latest stuff done

Bonotron - effect unit

A nice effect unit!

It was made by Bonotron, a company that still seems to be active in Karlskoga, Sweden.

Modifications on Doepfer A-110 VCO

Doepfer has a lot of nice synthesizer modules, and they often gives away the schematics. This leads to a lot of modification being made to enhance and enrich the already nice modules.

The A-110 VCO is easy to modify to get softsync and FM-input for a more complete function as a voltage controlled oscillator. The schematic is found here. The electronic part is really easy.

How to mount the extra jacks and switches

To make life simple, I did a small template for the drilling of the extra holes. It is very nice when all the holes are made equal on all VCO´s when making the modification on more than one module.The drilling itself was done by my dear wife, who is a silversmith and good at making nice holes in metal.

medium_Doepfer_A110_mod_holes.jpg

Here is the SVG-file. It contains one layer with the scanned panel and one layer with the drill guide. The SVG-file can be opened by Inkscape and adjusted. 

A110_borrning.svg

A nice picture of the A-110 after modification.

medium_Doepfer_A110_mod_backside.jpg

Fix dead buttons on a Roland MC-303

Long time ago, my main sequencer for musical excursions were the Roland MC-303. Maybe not the best in the world but sure did function well enough to have a lot of fun with. So, when a unit appeared for sale on the second hand market, I bought it.

To my great disapointment, the Swedish Postal Service ("Posten") did it´s worst to kill the unit. But instead of going to the complaints department I ripped it open to find the fault.

What was dead? Some very important buttons were completely unresponsive. The green circles shows which ones.

medium_Dead_buttons.png

The schematic clearly showed were to look if you consider which buttons that were dead. The wiring shows a normal way of scanning a lot of buttons using som logic.

medium_cut_pcb.png

And what did I find? A small crack on the PCB, just behind the "TAP"-button. It cut the PCB traces as shown above in the schematic.

medium_crack.jpg

And the fix (quick and dirty). The MC-303 now works perfectly.

medium_fix.jpg

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