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shaun

analogue synth servicing/repairs

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what are the symptoms?

have you any idea what is wrong with it? which stage is malfunctioning?

i'd hand it to an electronics engineer or someone similar before going anywhere near a local music shop.

if it's really precious to you there are places you could probably send it, funky junk in london springs to mind.

http://www.proaudioeurope.com/

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it's not totally dead. though, i did have a scare when i wouldn't go on for about 5 hours.

the same problems now still persist.

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jen sx1000

jen.gif

The Synthetone SX-1000 is an old Italian basic mono-synth. It has a single analog DCO with three waveforms: sawtooth, square, and PWM (Pulse Width Modulation). There is an analog filter (12dB/octave) with cutoff, resonance, and LFO modulation. There is also a simple ADSR envelope for shaping your sounds. In addition there are also white/pink noise generators a glide effect and a vibrato effect. It's known for fairly stable tuning too. Probably its best sounds are the lead ones, the basses aren't that deep but it sure can scream!

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You could also try Kenton Electronics' date=' they used to retrofit modifications to your kind of synth. They may be able to service it for you.

[url']http://www.kentonuk.com

The guys at Kenton don't do repairs.

There is a good chance the problem you are having is simply down to a faulty pot.

Looking at the schematic the pot is the only common component before the 301 Opamp, and likely if the Opamp had a problem you would get no sound at all.

Although I'm slightly puzzled as the post below says the SX-1000 has a single DCO and the schematic posted looks like a VCO so maybe thats the wrong schematic ?

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what does the d stand for in dco? is it digital?

Yes, although there are a number of different digital methods that are commonly used - most common being some sort of microprocessor control.

VCO = voltage controlled osc, usually using some sort of discreet or opamp based feedback loop to generate

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Guest Tam o' Shantie
The guys at Kenton don't do repairs.

Although I'm slightly puzzled as the post below says the SX-1000 has a single DCO and the schematic posted looks like a VCO so maybe thats the wrong schematic ?

The sound was generated by a single oscillator, described on the control panel and the voice cards (see box below) asa VCO, but by previous writers as a DCO. The truth is that it was a strange halfway house that was neither entirely voltage-controlled nor digitally controlled. It worked something like this... The oscillator itself was a high-frequency square-wave generator, stabilised by a digital circuit. So far, so DCO. The output from this was passed to a large 40-pin chip (which would now be almost impossible to replace) which shaped the wave into a wider selection of waveforms and divided it down to the standard range of audio frequencies. But what about the 'Fine Tune' control on the top panel? This, indeed, was a standard voltage control that affected the frequency of the high-frequency oscillator. The range of its affect was rather small but it was, nonetheless, a voltage control.

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The sound was generated by a single oscillator' date=' described on the control panel and the voice cards (see box below) asa VCO, but by previous writers as a DCO. The truth is that it was a strange halfway house that was neither entirely voltage-controlled nor digitally controlled. It worked something like this... The oscillator itself was a high-frequency square-wave generator, stabilised by a digital circuit. So far, so DCO. The output from this was passed to a large 40-pin chip (which would now be almost impossible to replace) which shaped the wave into a wider selection of waveforms and divided it down to the standard range of audio frequencies. But what about the 'Fine Tune' control on the top panel? This, indeed, was a standard voltage control that affected the frequency of the high-frequency oscillator. The range of its affect was rather small but it was, nonetheless, a voltage control.[/quote']

in context:

http://www.gordonreid.co.uk/vintage/sx1000.html

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