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Here are some Infos about Troubleshooting
Schematic JP8 - didn't match for all functions
https://manuals.fdiskc.com/flat/Roland%20Jupiter-8%20Service%20Maunal.pdf
VCF
https://www.ericasynths.lv/media/AS662D.pdf
https://alfarzpp.lv/eng/sc/AS3109.pdfhttps://manuals.fdiskc.com/flat/Roland%20Jupiter-8%20Service%20Maunal.pdf
Resonance failures:
works the resonance or only NOT the Self Oscillation ?
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