The Roland Juno-106 is one of the most iconic analog synthesizers of the 1980s. Known for its lush chorus, warm analog sound, and straightforward interface, it remains a favorite among musicians and producers. However, due to its age, many units suffer from common failures. In this post, we’ll go over the most frequent issues with the Juno-106 and how to repair them.
1. The Infamous 80017A Voice Chips (VCA/VCF)
Symptoms:
• Notes cutting out or not playing at all
• Filter behaving inconsistently
• Unstable sound or volume fluctuations
Cause:
The 80017A voice chips (which contain both the VCA and VCF) are coated with a resin that degrades over time, causing failure. This is one of the most common problems with the Juno-106.
Fix:
• Option 1: Clean and Restore
Some people have had success by removing the resin using acetone or other solvents, exposing the chip to remove corrosion. However, this is risky and may not always work.
• Option 2: Replace with New Voice Chips
Several third-party manufacturers now produce replacements (such as the Analogue Renaissance AR80017A). You can desolder the old chips and install these instead.
2. Chorus Noise (“Jet Engine” Sound)
Symptoms:
• The chorus effect produces a loud background noise
• A constant whooshing or “jet engine” sound
Cause:
The MN3009 BBD chips in the chorus circuit wear out, and aging capacitors contribute to noise issues.
Fix:
• Replace the MN3009 chips (new-old-stock or modern clones like Xvive MN3009)
• Replace electrolytic capacitors in the chorus section
• A quick “no-mod” fix is to replace resistor R151 with a 100kΩ value, reducing noise but altering the character of the chorus slightly
3. Intermittent Key Contacts
Symptoms:
• Certain keys do not respond or trigger inconsistently
Cause:
Dust, oxidation, or wear on the rubber key contact strips and carbon pads under the keys.
Fix:
• Open the synth and carefully remove the keybed
• Clean the rubber contacts and PCB traces with isopropyl alcohol (99%)
• If cleaning doesn’t work, replace the rubber contact strips (available from synth parts suppliers)
4. Dead or Flickering LED Buttons
Symptoms:
• Some of the buttons do not light up or flicker
• Some buttons don’t respond when pressed
Cause:
• Failing LEDs or worn-out tact switches under the buttons
Fix:
• Replace the LED if it’s dim or dead
• If the button doesn’t work, replace the tact switch (usually 6mm x 6mm switches)
5. Power Supply Issues
Symptoms:
• Synth does not power on
• Random reboots or glitches
Cause:
Failing electrolytic capacitors and voltage regulators in the power supply section.
Fix:
• Replace all electrolytic capacitors in the power supply
• Check and replace 7805 and 7812 voltage regulators if necessary
Final Thoughts
The Roland Juno-106 is a legendary synth, but due to its age, it often needs repairs. Thankfully, with the right tools and patience, many of these common issues can be fixed, keeping this classic machine alive for years to come.
If you’re not comfortable with soldering or disassembling your synth, consider reaching out to a professional synth technician. But for those who love DIY repairs, working on a Juno-106 can be a rewarding project.
Need a synth repaired? Get in touch with us here!
