Repairing & Restoring a Korg Polysix to Better Than New! Episode 5: Diagnostics/Repair, Calibration

This is episode five in the Polysix restoration series. In this episode, I diagnose the no-sound issue I discovered at the end of episode 4, diagnose and fix the filter resonance, calibrate the filters, envelopes, oscillators and effects, then add the special noise-reducing grounding circuitry. Lastly I test it and button up the case!

The very first synthesizer I ever bought, back in 1987, was a Korg Polysix. These venerable synths have a monster sound, but time is not kind to their inner electronics. In this video series, I will take a nonfunctional Polysix with severe internal damage and make it better than new, bringing modern capabilities, MIDI, and better quality sound while retaining what makes the PolySix so special! Join me on this restoration journey.

Polysix Restoration Episode 1: https://www.youtube.com/watch?v=w7xSVRn_ptc Polysix Restoration Episode 2: https://www.youtube.com/watch?v=fZUm2OaaAPg Polysix Restoration Episode 3: https://www.youtube.com/watch?v=zkCY7ygsWek Polysix Restoration Episode 4: https://www.youtube.com/watch?v=Hb-BbjQvr4s Polysix Restoration Episode 5: https://www.youtube.com/watch?v=yvufr7siFRs Polysix Restoration Episode 6: https://www.youtube.com/watch?v=eKCCYIqS5KQ

JD-800 Restoration Video: https://www.youtube.com/watch?v=23T7WGZgzJk SH-101 Restoration Video: https://www.youtube.com/watch?v=23T7WGZgzJk Poly-800 Restoration Video: https://www.youtube.com/watch?v=FXJFF97_sDc

Polysix Replacement Case: https://reverb.grsm.io/Polysix-Chassis Polysix Rubber Contacts: https://reverb.grsm.io/Polysix-Contacts Transformer: https://www.mouser.com/ProductDetail/553-VPT36-2780 Kiwisix Upgrades: https://www.kiwitechnics.com/kiwisix.htm Vessel JIS Screwdrivers: https://amzn.to/3hN1RKE Thermal Transfer Grease: https://amzn.to/3jJhBir CaiKote 44: https://amzn.to/3Q0S3cv Pro Honda Spray Cleaner: https://amzn.to/3YN7Ak5 DeoxIT D5: https://amzn.to/3WqWQ9C DeoxIT Fader F5: https://amzn.to/3hTs22g Anhydrous Isopropyl Alcohol: https://amzn.to/3FYcfag Spark Arresting Capacitor: https://www.mouser.com/ProductDetail/80-R474I233050A1KV57 Thermal (infrared) camera used: https://amzn.to/3XbEIRk

0:00 Intro 0:35 Where Are We? 1:28 Initial Filter Calibration 2:13 Diagnosing No Sound 6:13 Calibrating Filters - No Resonance 6:46 Diagnosing No Filter Resonance 8:08 Resonance Fixed, Filter Calibration 9:14 Recap 15:11 Tuning Concepts 16:57 Heat Required! 18:04 Tuning Oscillators 19:30 Calibration Completed 20:29 Noise Floor 21:00 Grounding to Reduce Noise 26:42 Testing - No Sound Again! 28:04 Measuring New Noise Floor 28:48 Are we done? 29:47 Final Reassembly 31:16 Summary - What's Next?

#Korg #Polysix #Kiwisix ... https://www.youtube.com/watch?v=yvufr7siFRs