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Juno 106 lives

Posted: Fri May 15, 2009 11:35 pm
by Alexlin
Hallo there,
here comes another fresh Juno 106 owner facing the mystery of analog Synthesizers and their world of possible problems and not having a clue "what the F* is going on"

Let's meet the problem:
1) I turn on my fantastic Juno 106, ...lights blink, blink a subtle but charming buzz goes through the air,..lovely.
2) I start to play, evolve into the highs of synthesis, oh what a joy ...
3) Time passes.....sometimes 15 min, sometimes 2 hours till part 4) strikes
4) Suddenly like an evil virus, lovely Juno starts to create a life of his own. Coming to the point: suddenly one note hangs and doesn't stop anymore. Eventually it becomes softer or louder, sometimes it even stops but it comes BACK! If I press other keys the hanging note jumps "almost" every 6. half step to this next tone. (though it it is not always happening that regular)
5) Me getting totally frustrated and almost want to through the whole thing out of the window, but catch my self at the last moment with a glimpse of hope that there is somebody out there who can help me.

......INTERNET......

All right enough History and Drama.
I talked to people who advised me to exchange the 3 voltage controllers (I'm not sure if this is the right word in english - I refer to the small things that might get overheated when they are to old and therefore cause problems - in dutch they are called "spanningsregelaars")
They said if I'm really lucky my problem might be solved with this exchange otherwise could it maybe be one of the oszilators??

I really would appreciate any tip idea or advice what it could be and how I could fix it. I'm so excited about this machine and wanna play it.

Thanks already for any respond

Re: Juno 106 lives

Posted: Sat May 16, 2009 1:03 am
by magnus
This is a classic Juno 106 problem - it's a cursed synth. I used to love my Juno, but these days it just lives under the bed. The VCF/VCA chips in alot of 106s were dodgy, and prone to failure - I've replaced 2 so far, and 2 more are on their way out. Check out this website: http://www.analoguerenaissance.com/D80017/ - his cloned chips are apparently the best on the market. I think they're 50 euros each. Don't be surprised if you end up spending more on repairs than you did on the Juno. There are 6 potentially faulty chips in there, and if 1 has failed, they probably all will eventually. Don't waste your money on chips salvaged from old Junos, as they will fail too.

And when you find yourself hunched over your 106, soldering iron in hand, for what feels like the 100th time, try not to think about the Juno 60!

Re: Juno 106 lives

Posted: Sat May 16, 2009 5:42 am
by cornutt
Yeah, it's the classic 80017A problem. Do a search here in the HELP forum for "80017" or "800017" and you'll find lots of threads.

Re: Juno 106 lives

Posted: Sat May 16, 2009 11:09 am
by HideawayStudio
cornutt wrote:Yeah, it's the classic 80017A problem. Do a search here in the HELP forum for "80017" or "800017" and you'll find lots of threads.

Just find a friend who can solder and change the 80017A out with a clone. I say this as the bulk of your repair costs will simply be labour. The Juno has a built in diagnostics mode which will help pinpoint the faulty chip. Seriously - it's not a difficult repair by someone who can solder (or more to the point desolder!) - and well worth it - the 106 is a lovely synth.

I've not known of clones failing so once your modules are replaced your synth should be pretty reliable. Fortunately the rest of the 106 is pretty trouble free.

Re: Juno 106 lives

Posted: Sat May 16, 2009 1:23 pm
by Alexlin
Hey thanks so much for all your advice,
so if I get it right a 80017A is what I call the Oszilator?
How glad am I to hear that someone makes clones, I already was horrified and ready to hunt an old chip.

To detect the false chip with the test mode don't I need a oscilloscope?

And what I asked about those voltage control chips does anybody think I should exchange them as well?

Greetings Alexlin

Re: Juno 106 lives

Posted: Sat May 16, 2009 1:59 pm
by HideawayStudio
Alexlin wrote:Hey thanks so much for all your advice,
so if I get it right a 80017A is what I call the Oszilator?
How glad am I to hear that someone makes clones, I already was horrified and ready to hunt an old chip.

To detect the false chip with the test mode don't I need a oscilloscope?

And what I asked about those voltage control chips does anybody think I should exchange them as well?

Greetings Alexlin

You don't need any test gear to check which chip has failed. The 80017A is a combined VCF (Voltage Controlled Filter) and VCA (Voltage Controlled Amplifier) - the VCA handles the envelope control for each voice. The Oscillators are provided by another chip - the MC5534 which are generally quite reliable.

There is a good writeup on the 80017A here:

http://matrixsynth.blogspot.com/2007/05 ... 0017a.html

Re: Juno 106 lives

Posted: Sat May 16, 2009 5:19 pm
by magnus
No - don't touch the voltage controllers, whatever they are. I don't know why they gave you that advice - when a Juno 106's voice starts failing, the VCA/VCF chip is always the best bet. Get a soldering iron,some solder, and a solder sucker or some of that wiry stuff, and follow this: http://blowintopieces.com/blog/2006/10/ ... -juno-106/ It will tell you everything - I'm no electronics whizz, but I found the repair easy enough with these instructions

Re: Juno 106 lives

Posted: Sat May 16, 2009 5:41 pm
by cornutt
Alexlin wrote:Hey thanks so much for all your advice,
so if I get it right a 80017A is what I call the Oszilator?
No, it contains the VCF and the VCA. The oscillators (DCOs) are in some other chips, which look kind of similar. If you opened up the 106 and looked at the module board, which is the longer board on the left, you'd see 9 ICs that look like long, skinny lumps of plastic. They stick up further than the other ICs on the board, and they have all of their pins in a single row. They are in groups of 3. In each group, the left and right ones are the VCF/VCA chips (marked with the part number 80017A) for one voice each, and the center one is the DCO chip for two voices. Except for the very early production models, there is silkscreening on the bottom edge of the board that shows which chips go with which voices.
To detect the false chip with the test mode don't I need a oscilloscope?
Nope. You put it test mode and play some notes. Every time you play a note, the numeric display tells you which voice is sounding. When you hit a bad note, you just look at the display to see which voice it is.
And what I asked about those voltage control chips does anybody think I should exchange them as well?
Don't mess with the DCO chips. They almost never fail.

BTW, once you have replaced the bad 80017A, you will have to do a calibration. There are threads here about that.

Re: Juno 106 lives

Posted: Tue Jun 09, 2009 12:57 am
by Alexlin
You guys here are the best thing that can happen to an vintage synth. I got one of those cloned chips and exchanged it with the broken one and guess what it wooooorks. Super. Now all that is left to do is to calibrate the thing. Anybody has maybe a tip, tutorial ..etc?

I am also looking for an software oscilloscope to download.

Thanks
Best greetings
Alex Lin

Re: Juno 106 lives

Posted: Tue Jun 09, 2009 8:44 am
by Ashe37
Problem with a software oscilloscope would be that you need probes etc- i don't think there are any softeware only ones

Re: Juno 106 lives

Posted: Tue Jun 09, 2009 3:44 pm
by Alexlin
Is there a software oscilloscope that I can use with Logic 8? Maybe a VST plug in?

Re: Juno 106 lives

Posted: Tue Jun 09, 2009 10:49 pm
by Alexlin
Looked around in the net and eventually came across a AU plug for Logic pro.

http://sonictransfer.com/free-vstau-oscilloscope.shtml

Works all fine just now how to do it? The description in the manual is informative and confusing at the same time.

Some tips would be still well appreciated.

Thanks

Re: Juno 106 lives

Posted: Tue Jun 09, 2009 11:22 pm
by pflosi
i guess you would have to monitor the signal of the juno for the oscilloscope :)

for calibration, check this:

http://www.flitemedia.com/studio/roland-juno106.php

cheers

Re: Juno 106 lives

Posted: Fri Jun 19, 2009 1:39 am
by Alexlin
Mission completed,
thanks again to all of you for your really helpful advice. Chip is replaced, everything calibrated and it works just great.

Best greetings AlexLin

Re: Juno 106 lives

Posted: Fri Jun 19, 2009 6:59 pm
by pflosi
good to hear that.