In my late teens I bought this 70’s italian transistor organ from a neighbor and I played it heavily during my psychedelic-rock days. Later it made it’s way into surf music, but one day it developed some serious hum and was put aside for more than a decade.
Finally the time was ripe to rescue this gem. The „Viscount Synth Dakota“ features a strange little „Synth Effect“ section. It is not a real synth, more a polyphonic piano/harpsichord-like tone generator with a modulated filter section. Quite unique in this combination with a straightforward cheese-organ. And another cool thing: it has an onboard spring reverb!
The typical first guess for the source of hum is one or more defective capacitors in the power supply. So I searched for the right board. It was easy to find: just follow the wires coming from the power-cord’s socket. Due to the pretty good design of the organ, that allows you to simply flip the two keyboard-layers, the little board with the rectifier, the big capacitors and the huge resistors is well accessible.
The two biggest capacitors were blown, you can see this in the photos. I changed all the capacitors in the power-supply, even the ones that looked ok. These are cheap components and not much work to change. After more than 40 years it’s a good idea to replace them. I also ordered replacement for the 5 or 6 big capacitors on the other boards.
Now the hum is gone. There is some minimal ripple in the supply, but it does not make it’s way to the tone-output. In the next step I will change the other capacitors an clean all the mechanical contacts. Some of the keys are quite scratchy. Then the baby will be ready for the next decades of electro-swing.