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Roland SH5 Synthesiser circa 1976

£1,500.00 (Sold out)

Roland SH5 Synthesiser circa 1976

Not working properly, see engineers report.

Engineers Report:

Notes on the Roland synth

The failed 15 volt positive regulator circuit has been repaired, this also feeds into the 10 volt regulators. This is now a working synth but needs quite a lot of additional work to make it usable in any real sense.

The VCA and the Envelope shaper do not work. The ES is permanently open and there is no means of adjusting the note loudness from the VCA circuit. The VCA is not triggered by either the LFO circuit nor is it triggered from the keys and thus it is not doing its job. The VCF too should be able to follow the keys such that its effect tracks playing across the keyboard. This doesn't work either although the filter will self oscillate and can be modulated from the LFO.

The ring modulator doesn't seem to work as it should either. Mixing tones should generate a rich collection of harmonics but the outputs seem to be missing this.

My guess is the the failure of the positive supply has caused damage to the old integrated circuits in both the key gating circuits and in the VCA/ADSR/AD stages all of which would require extensive work to put right. The wire ended IC's that were used in this and many other Roland mono synths of the time have not been available for over 15 years and it is doubtful that supplies have improved since then.

The mixer, oscillators and part of the keys interface seem to work okay.

The cost to modify the synth to cure these issues is likely to be between £500 and £750 and take a considerable time.