I have a vintage Siel Cruise that I recently got off Ebay here in Germany. Sadly, the synth was lost in the mail for 6 weeks and I think it might have been damaged during its turbulent times.
The Cruise has pretty much no output. There is the faintest of signal coming out and corresponds to the keyboard… Meaning, that the keyboard is tracking. I hit an E it plays an E I hit a C it plays a C… So on. I’ve been inside it a few times and I just can’t figure out the low output. Everything seems to be correct seated properly and such…
I haven’t looked at it in two months, but after looking at the schematic again I noticed that maybe all the signal passes the DIN Volume jack. You can connect a volume/expression pedal to control the overall output of the Siel Cruise. Could it be possible that the DIN is broken internally and maybe is dumping all the audio to ground? Its a really cool synth/string machine that I would love to get working again. Below is a link to the schematic. Anyone who could provide some insight into why there is such little output please let me know. Cheers.
https://www.polynominal.com/siel-cruise/Siel_Cruise_Schematics.pdf