Vintage Synth Explorer Forums

I'm not experienced at all with synths, I just bought a Juno 106 off ebay wanting to start somewhere hearing good things about analogs and this one in particular. I figured i could work my way up to a more complex and modern piece of equipment in time...but I think my synth has a problem...

It has a constant tone playing no matter if a key is pressed or not and its as soon as its turned on with whatever the default bank and patch is selected...some patches have it as soon as you select them and others not...if it does then when you do press a key that constant tone shifts to whatever note/key was pressed. It seemed also that it was fainter at first but now its as loud as if a key were constantly being held down and is intolerable and overpowering. ALSO, on some patches when there is nothing but silence I get this scratchy sound coming through my headphones like there is a bad connection. I havent tried an amp, and maybe its completely unrelated and just the jack or maybe its part of the same problem. To me it sounds most obviously like theres a problem..does anyone know what it could be or how much it would be to repair something like this? Ive become very discouraged this being my first synth an all...HELP!

Need to verify the transistors, op-amps and electrolytic capacitors. And obviously the VCF/VCA chips.

If you don't know how to test components and to replace them, please see a tech. This is not jus a "loose wire" or something like that. Have it revised.

I am sad to see you have encountered the nightmare of vintage synths on your first try. These synths are not new anymore, and need servicing of dried out capacitors or broken specialized IC chips in many cases.

When you get into the old analog business, it's a tradeoff. You're bound to have something break down completely, at some point. Electronics have a lifespan, and these early 80's/70's synths are going past that lifespan nowadays. That being said, I owned a Juno106 that worked perfectly.
Guess it was luck. I also have a few VERY old analog synths that still work smoothly. But they've been serviced in the past before I bought them.

Sounds like the infamous 80017A chip failure. Juno-106s are notorious for these.

The good news is, once you replace the bad chip(s), the synth should be in good shape. You'll just have to find the chips and someone who is decent at soldering who can replace them for you.

It does sound like the dreaded 800017A. There's another thread around here that describes how to get into the test mode and figure out which voice is bad. After that, it's just a matter of unsoldering the dead one and putting in a good one. The 800017A is available from various sources for about $60 US, if you Google around; they also turn up on Ebay from time to time.