Uploaded January 2023 | Updated September 2026, 2 weeks ago
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!
Note: I had several people notice that I mentioned the bank buttons weren't working, but not what was wrong with them. I didn't realize until later that I didn't mention this in the video. The problem with the buttons was the same problem as the resonance and filter cutoff: oxidized contacts on cable connectors. Cleaning the contacts with Deoxit D5 solved the issue.
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: youtube.com/watch?v=w7xSVRn_ptc
Polysix Restoration Episode 2: youtube.com/watch?v=fZUm2OaaAPg
Polysix Restoration Episode 3: youtube.com/watch?v=zkCY7ygsWek
Polysix Restoration Episode 4: youtube.com/watch?v=Hb-BbjQvr4s
Polysix Restoration Episode 5: youtube.com/watch?v=yvufr7siFRs
Polysix Restoration Episode 6: youtube.com/watch?v=eKCCYIqS5KQ
JD-800 Restoration Video: youtube.com/watch?v=23T7WGZgzJk
SH-101 Restoration Video: youtube.com/watch?v=23T7WGZgzJk
Poly-800 Restoration Video: youtube.com/watch?v=FXJFF97_sDc
Polysix Replacement Case: reverb.grsm.io/Polysix-Chassis
Polysix Rubber Contacts: reverb.grsm.io/Polysix-Contacts
Transformer: mouser.com/ProductDetail/553-VPT36-2780
Kiwisix Upgrades: kiwitechnics.com/kiwisix.htm
Thermal Transfer Grease: amzn.to/3jJhBir
CaiKote 44: amzn.to/3Q0S3cv
Spark Arresting Capacitor: mouser.com/ProductDetail/80-R474I233050A1KV57
Tools:
Anhydrous Isopropyl Alcohol: amzn.to/3FYcfag
Pro Honda Spray Cleaner: amzn.to/3YN7Ak5
3M Spray Adhesive: amzn.to/3mg87wF
Vessel JIS Screwdrivers: amzn.to/3hN1RKE
Desoldering Pump: amzn.to/40bh8Vu
Soldering Station: amzn.to/3ofPgCz
DeOxit D5 Contact Cleaner: amzn.to/3mIihpT
DeOxit F5 Fader Cleaner: amzn.to/3KGZ8Nj
Rigol DS1054Z Oscilloscope: amzn.to/3VghKIw
Thermal (infrared) camera: 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
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!
Note: I had several people notice that I mentioned the bank buttons weren't working, but not what was wrong with them. I didn't realize until later that I didn't mention this in the video. The problem with the buttons was the same problem as the resonance and filter cutoff: oxidized contacts on cable connectors. Cleaning the contacts with Deoxit D5 solved the issue.
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: youtube.com/watch?v=w7xSVRn_ptc
Polysix Restoration Episode 2: youtube.com/watch?v=fZUm2OaaAPg
Polysix Restoration Episode 3: youtube.com/watch?v=zkCY7ygsWek
Polysix Restoration Episode 4: youtube.com/watch?v=Hb-BbjQvr4s
Polysix Restoration Episode 5: youtube.com/watch?v=yvufr7siFRs
Polysix Restoration Episode 6: youtube.com/watch?v=eKCCYIqS5KQ
JD-800 Restoration Video: youtube.com/watch?v=23T7WGZgzJk
SH-101 Restoration Video: youtube.com/watch?v=23T7WGZgzJk
Poly-800 Restoration Video: youtube.com/watch?v=FXJFF97_sDc
Polysix Replacement Case: reverb.grsm.io/Polysix-Chassis
Polysix Rubber Contacts: reverb.grsm.io/Polysix-Contacts
Transformer: mouser.com/ProductDetail/553-VPT36-2780
Kiwisix Upgrades: kiwitechnics.com/kiwisix.htm
Thermal Transfer Grease: amzn.to/3jJhBir
CaiKote 44: amzn.to/3Q0S3cv
Spark Arresting Capacitor: mouser.com/ProductDetail/80-R474I233050A1KV57
Tools:
Anhydrous Isopropyl Alcohol: amzn.to/3FYcfag
Pro Honda Spray Cleaner: amzn.to/3YN7Ak5
3M Spray Adhesive: amzn.to/3mg87wF
Vessel JIS Screwdrivers: amzn.to/3hN1RKE
Desoldering Pump: amzn.to/40bh8Vu
Soldering Station: amzn.to/3ofPgCz
DeOxit D5 Contact Cleaner: amzn.to/3mIihpT
DeOxit F5 Fader Cleaner: amzn.to/3KGZ8Nj
Rigol DS1054Z Oscilloscope: amzn.to/3VghKIw
Thermal (infrared) camera: 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
