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 Forum index » Instruments and Equipment » General Discussion
My small Juno-106 repair thread
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shelfpaper



Joined: Aug 27, 2010
Posts: 10
Location: USA

PostPosted: Mon Sep 06, 2010 2:59 am    Post subject: Reply with quote  Mark this post and the followings unread

I'm not much of a repairman (4 or 5 guitar amps, no synth work yet), but it might be worthwhile to look for burnt or unsoldered components and damaged PCB traces in the noise generator part of the circuit. You can try a magnifying glass, but what I usually do is take a close-up digital photo of the area and view it at full resolution on the computer.
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my05



Joined: Jan 02, 2010
Posts: 26
Location: stockholm, sweden

PostPosted: Mon Sep 06, 2010 4:30 am    Post subject: Reply with quote  Mark this post and the followings unread

shelfpaper wrote:
I'm not much of a repairman (4 or 5 guitar amps, no synth work yet), but it might be worthwhile to look for burnt or unsoldered components and damaged PCB traces in the noise generator part of the circuit. You can try a magnifying glass, but what I usually do is take a close-up digital photo of the area and view it at full resolution on the computer.


Hi,

That is an excellent advice. Unfortunately, i haven't been able to notice any bad traces on the board (and i have tried very hard to look at exactly this).

What struck me yesterday was that a lot of people recommended me to check the "TR-22" on the module board. While looking at the service manual, i could never find this transistor. Problem was that i was looking at the wrong image (stupid me Smile). What i should have looked for was marked "Q22" (which equals TR-22 in some other schematics).

While i did swap the "NZ" for a new one (as per my earlier post) which did not work, i should have focused on the "Q22" (2SC-1015Y transistor) as per the image below:

Posted Image, might have been reduced in size. Click Image to view fullscreen.

i have ordered a few of these transistors and keep my fingers crossed that it is the missing link for the white noise problem. I'll keep you posted.

Kind regards

Daniel


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radar23



Joined: Apr 28, 2009
Posts: 2
Location: australia

PostPosted: Wed Sep 29, 2010 8:47 pm    Post subject: mks80 noise generator Reply with quote  Mark this post and the followings unread

I have the same problem with a MKS-80.

the noise generator makes noise but ever so slightly... It can only be heard when the master volume is up full and the output is gain up with a mixer. Then you can hear it.

Lead me to believe some simple may be the problem.

If anyone could come up with a suggestion to assist, then please do

Thanks

Radar
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jc175



Joined: Jun 05, 2010
Posts: 3
Location: Australia

PostPosted: Fri Nov 05, 2010 10:01 pm    Post subject: Reply with quote  Mark this post and the followings unread

my05 wrote:
What struck me yesterday was that a lot of people recommended me to check the "TR-22" on the module board. While looking at the service manual, i could never find this transistor. Problem was that i was looking at the wrong image (stupid me Smile). What i should have looked for was marked "Q22" (which equals TR-22 in some other schematics).


Hey Daniel,

had any luck?
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EnochLight



Joined: Feb 27, 2011
Posts: 3
Location: Michigan

PostPosted: Sun Feb 27, 2011 1:44 pm    Post subject: Replacing keys on a Juno 106 Reply with quote  Mark this post and the followings unread

Greetings everyone - new to the forum here. I found this thread via a Google search while querying the phrase "Juno 106 key replacement".

I've had a 106 since 1990, and it's in great condition and works perfect (haven't experienced the voice problem yet - knock on wood), but due to a theft and vandalization about 10 years ago, 2 of the keys were broken. Clearly the vandals didn't realize its worth, and thankfully left it behind - after smashing 2 of the keys... Sad

I found replacement keys on eBay (springs are fine) and would like to replace them myself, and have no problem opening my 106 up (I've done this in the past to clean the keys thoroughly and dust the components).

My problem is: I can't figure out how to pull they keys off! The springs are easy, but they appear physically attached or hinged in the back. Can anyone point me in the right direction?

Cheers!
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TonyHex9



Joined: Mar 23, 2011
Posts: 4
Location: Philadelphia

PostPosted: Wed Mar 23, 2011 6:19 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi there, I've lurked on the board for years and finally joined today! I'm also in the process of restoring a Juno 106. I got it from a friend who's had it rusting against a wall in a warehouse for several years. After jury-rigging up a power cord it powered on just fine, and made the most beautiful sounds. The voices all work and the controls mostly work despite a broken key, several snapped off sliders, and a broken pitchbender.

The things that don't work: A few of the keys never sound notes, including almost an octave's worth of keys in the lower register. Also, the suboctave works fine except it doesn't sound on just one of the C notes. Weird huh?

There also appears to be about 3 decades worth of dead spiders and cobwebs under the hood.

I'm in the process of removing the dust and bug parts from the inside. I removed the keyboard and I'd like to fully disassemble it, as this is where lies the bulk of the nastiness. Like EnochLight I'd can't figure out how to get the keys apart.

Have you had any luck yet Enoch?

Any thoughts on what could be causing the silent keys? Mechanically they feel fine except I know there are a million little buggy exoskeletons in them. Does anyone think the keys might magically work after a thorough cleaning?
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TonyHex9



Joined: Mar 23, 2011
Posts: 4
Location: Philadelphia

PostPosted: Wed Mar 23, 2011 7:43 pm    Post subject: Reply with quote  Mark this post and the followings unread

OK! I figured out how to remove the keys. First you must remove the little spring at the back of the key. On my 106 the key is still locked in place by two long thin strips of clear flexible plastic that run the entire length of the underside of the keyboard. These strips are glued on with what seems to be a temporary glue. I pried one of the strips off easily with my fingernail and then the keys can just pop out once the springs are removed. God, they are filthy. Hopefully it won't be too hard to glue that plastic strip back in when I'm reassembling. Maybe I'll use rubber cement.
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TonyHex9



Joined: Mar 23, 2011
Posts: 4
Location: Philadelphia

PostPosted: Thu Mar 24, 2011 12:37 am    Post subject: Reply with quote  Mark this post and the followings unread

Took this picture before I cleaned all the gunk off the board with a toothbrush. The circuit board looks healthily green now. bounce

I let all of the keys soak for a bit in a tub full of hot soapy water. Cleaning the scum off of them all with a toothbrush while listening to Brian Eno brought me to a very zen plateau. Recommended.


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EnochLight



Joined: Feb 27, 2011
Posts: 3
Location: Michigan

PostPosted: Thu Mar 24, 2011 11:27 am    Post subject: Reply with quote  Mark this post and the followings unread

TonyHex9 wrote:
..Have you had any luck yet Enoch?


I have actually!

That said, unlike what you did, I got my broken keys off after I removed the lower metal bracket by unscrewing the 6 screws from the bottom front edge and resting the metal strip on the bottom (as I didn't want to unscrew the ground wire that's screwed to it). Anyway, after I removed that lower bracket, I was able to just take a pair of pliers and pull the keys out - unsnapping them from those plastic strips you mentioned.

Afterwards, I just snapped the new keys in, reattached the springs, and off I went. Took some time to blow out some dust with some electronics compressed air and vacuumed up a bunch of cobwebs. I'm very happy to have my 106 back - and weirdly enough - the mainboard battery still has enough charge to store bank preset changes! I don't know how much longer it will last after 26 years, but I'm amazed it stored some changes. I fear the day it must be replaced, as it is soldered to the mainboard. I don't have enough electronics experience or skill to attempt that sort of replacement.


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TonyHex9



Joined: Mar 23, 2011
Posts: 4
Location: Philadelphia

PostPosted: Thu Mar 24, 2011 11:49 pm    Post subject: Reply with quote  Mark this post and the followings unread

That looks beautiful. Nicely done, thanks for posting the pictures!

After cleaning everything inside the synth that was reachable without removing the voice and power boards, I put it all back together to see if any of my problems are solved. Unfortunately, the same keys that were dead before are still dead. But on the bright side I didn't break anything.

I'd really like to get this synth back to 100% functionality. I've discovered a couple of problems and plan on doing a bit of testing for more info. I'm going to post my findings and most likely some questions for the board.

A question for anyone: Should I continue posting questions about the 106 in this thread, or will I get more of a response by starting a new thread?
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EnochLight



Joined: Feb 27, 2011
Posts: 3
Location: Michigan

PostPosted: Sun Mar 27, 2011 2:19 pm    Post subject: Reply with quote  Mark this post and the followings unread

TonyHex9 wrote:
That looks beautiful. Nicely done, thanks for posting the pictures!

After cleaning everything inside the synth that was reachable without removing the voice and power boards, I put it all back together to see if any of my problems are solved. Unfortunately, the same keys that were dead before are still dead. But on the bright side I didn't break anything.

I'd really like to get this synth back to 100% functionality. I've discovered a couple of problems and plan on doing a bit of testing for more info. I'm going to post my findings and most likely some questions for the board.

A question for anyone: Should I continue posting questions about the 106 in this thread, or will I get more of a response by starting a new thread?


Thank you!

Not sure if I'd go through the trouble of starting a whole new thread, as this one seems to have a lot of info and knowledge from other posters that could be useful for others in the future. Plus, posting to it seems to resurrect the thread no matter how old it is. It already has 4552 views and the OP might eventually chime in again.

I've heard of your problem before (certain keys or key ranges not functioning when everything else seems to function fine). A good way to test to see if it's the actual keys PCB (with the rubber contacts) is to hook it up via MIDI to another controller or a sequencer and see if you can control the range of bad keys (or key) that isn't working. If it works by using it via another MIDI controller/sequencer, then it's the keys PCB with the rubber contacts. You may be able to clean those rubber contacts or you may have to replace the entire keys PCB.

Good luck!
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playthatbeat



Joined: Jul 05, 2011
Posts: 1
Location: eire

PostPosted: Tue Jul 05, 2011 8:55 am    Post subject: Reply with quote  Mark this post and the followings unread

yup, i had that noise problem.. replaced the noise generating tranny and the amp tranny from the noise circuit with ultra-nasty generic a1015 and a c1815 (q21 and q22), then was about to go mad when i decided to try the SERVICE MODE, and lo, the noise was fine..

So, go into service mode: boot holding the KEY TRANSPOSE as usual, then select BANK button 6, in POLY 1 mode - then when you play a key you should hear the test tone drenched in lovely noise, er, maybe..

This bypasses the control panel for calibration (pot VR32 i think) of noise level - BUT proves the NG is working fine in my unit.. So, i replaced the gammy slider and i can has noise now! (thanks vintageplanet!)

I swapped back in the original transistors for the circuit, and could not tell the difference.. So, don't fret of you pop the NZ tranny - it can be any CHEAP amp tranny, in fact, the cheaper, the better the noise.. better quality transistors tend to have a more metallic feel, the cheapest of the cheap is the way to go.. In fact, the one used by Roly in the 106 was so awful, it was discontinued! But, you can still get them a Mouser, together with a warning about them being crappy, and to go for something more awesome..

Anyways, a shorted (easy with smoke in the lifetime) slider WILL NULL A FUNCTION - remember the sliders are doubles after all, and do more then attenuate!

All i have to do now is replace the SUB BASS slider - currently it is loudest in the middle!

also: if you get the 'dots' problem - that is, when you select a patch, then after a while the 2 DOTS appear in the display, to show it's been edited, yet you didn't touch anything - YOU HAVE GAMMY SLIDERS.. enjoy your random..

Wink

edit: oh the dead keys thing? i had that.. you need to take off the key, and under it is a rubber membrane, the underside of which has a carbon disc - this shorts 2 copper tracks on the keyboard board, so clean both the pad and the board area with an isopropal swab, then you are good to go..

you'll get the hang of removing keys, there is a trick to it!
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my05



Joined: Jan 02, 2010
Posts: 26
Location: stockholm, sweden

PostPosted: Tue Aug 16, 2011 1:53 am    Post subject: The light in the tunnel... perhaps :-) Reply with quote  Mark this post and the followings unread

Hi,

It's been a while. Since the last time i have effectively removed all keys from the keybed, washed them up, cleaned the underlying strips with isopropanol (in the process bringing my dead C4 to life again).

I have measured everything i can voltagewise with a multimeter (and everything on the power-board and module-board are within the stipulated voltage-levels).


- Pin 14 on IC-22 gives a span of between 0 and 15 when i pull the "noise"-lever
- BA662/IC-14 is swapped for a new one (i will measure pin 2 and 8 according to a tip i got on the 99musik.se forum)
- Exchanged Q22 against a new transistor, a 2SC-1015Y.
- Exchanged Q21 (2SC-945P) against an alternative variant named "NTE289A"
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my05



Joined: Jan 02, 2010
Posts: 26
Location: stockholm, sweden

PostPosted: Mon Dec 19, 2011 10:18 am    Post subject: It finally works
Subject description: horray
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Hi,

To finish off this topic, now everything works. The problem was the BA662 which had to be replaced AGAIN (the chip i got from Roland was faulty). Weird indeed, but finally i can close the lid for good and start using the thing Smile

regards

Daniel

(now, over to getting the aftertouch on my JX8P to start working again..... but that is another thread)
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dougt



Joined: Jun 16, 2007
Posts: 42
Location: Silicon Valley, CA, USA

PostPosted: Wed Dec 21, 2011 2:02 pm    Post subject: Reply with quote  Mark this post and the followings unread

Great, glad you got it finally working. I have tested, working BA662s if you ever need another one.
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Oddeo



Joined: Jan 11, 2012
Posts: 1
Location: Texas

PostPosted: Wed Jan 11, 2012 9:44 pm    Post subject: Reply with quote  Mark this post and the followings unread

I replaced one of my chips about two years ago and everything has been going well. I put my Juno106 in the closet for six months and now I am getting a lot of static if I tap my volume knob. Any tips on how to fix the issue?

Thank you,

Neil
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jc175



Joined: Jun 05, 2010
Posts: 3
Location: Australia

PostPosted: Tue Feb 07, 2012 6:23 pm    Post subject: Re: It finally works
Subject description: horray
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my05 wrote:
Hi,

To finish off this topic, now everything works. The problem was the BA662 which had to be replaced AGAIN (the chip i got from Roland was faulty). Weird indeed, but finally i can close the lid for good and start using the thing Smile

regards

Daniel

(now, over to getting the aftertouch on my JX8P to start working again..... but that is another thread)


So the BA662 was the issue that prevented the noise from working, eh? Delicious. I never managed to fix mine, but very recently I've had three voices decide to start dying simultaneously so it may not be my first priority...
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Ojd



Joined: Feb 22, 2008
Posts: 65
Location: Ua
Audio files: 1

PostPosted: Fri Jul 13, 2012 4:05 am    Post subject: Reply with quote  Mark this post and the followings unread

Hello. I'm repairing juno 106 too. There are major problems.
1. Attack seems to be from 200 ms to 2000 ms. I want to have snappy 0 ms attack too! What's wrong? I've swapped attack fader and delay rate fader - no luck.
2. Voice chips. The usual.
3. Wave chips. Will soaking in acetone help me?
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