HELP Roland Juno 106 3rd voice plays double note

Pulling out your hair? Don't know what to do or where to go? Ask in here.
Forum rules
READ: VSE Board-Wide Rules and Guidelines

If your Help request has been solved, please edit your first post in order to select the Image Topic Icon to let others know your topic has been solved.
Post Reply
ChuckFalcon
Newbie
Newbie
Posts: 57
Joined: Fri Jun 27, 2014 3:24 am
Real name: Chuck Falcon
Gear: Roland Promars MRS-2
Vox Continental
Mellotron M4000D
Roland Juno 60
Moog Theremini
Roland Juno 106
Akai MPC 1000
Band: Chuck Falcon

HELP Roland Juno 106 3rd voice plays double note

Post by ChuckFalcon » Tue Oct 11, 2016 11:41 am

Hey everyone,I have an old Roland Juno 106 that I love and it works perfectly EXCEPT, that while using the triangle wave, every 3rd voice will play a double and possibly a triple note. Ive already done the whole acetone bath for my voice and waveform chips and it didn't help it at all.

Here is a video of what it's doing:

Has anyone else had this experience or know what it could be or what I could do to fix it? Any info at all, I would be most appreciative.
Last edited by ChuckFalcon on Sun Nov 06, 2016 3:40 pm, edited 1 time in total.

ChuckFalcon
Newbie
Newbie
Posts: 57
Joined: Fri Jun 27, 2014 3:24 am
Real name: Chuck Falcon
Gear: Roland Promars MRS-2
Vox Continental
Mellotron M4000D
Roland Juno 60
Moog Theremini
Roland Juno 106
Akai MPC 1000
Band: Chuck Falcon

Re: HELP Roland Juno 106 3rd voice plays double note

Post by ChuckFalcon » Wed Oct 12, 2016 3:31 pm

I discovered the pattern this morning.

When the 3rd voice fires, it plays exactly what the 4th voice played LAST time.

EXAMPLE: First pass: (V1)C, (V2)D, (V3)E, (V4)F, (V5)G, (V6)A
Second pass: (V1)C, (V2)D, (V3)E and F, (V4)A, (V5)B, (V6)C
Third pass: (V1)C, (V2)D, (V3)E and A, and so on....

ALSO.... if I play for example "E" on the 4th voice and then I play that same "E" on the 3rd voice I will only hear JUST that 1 E, but it sounds a little quieter and a little muffled.

I took out the 4th voice chip and tried the same experiment and the 3rd voice still plays the 3rd note plus what the 4th voice WOULD have played. I also swapped voice chips around and it didn't change a thing.

Any idea what the heck is going on?

User avatar
garranimal
Synth Explorer
Synth Explorer
Posts: 1728
Joined: Mon Sep 27, 2004 8:57 pm
Location: USA
Contact:

Re: HELP Roland Juno 106 3rd voice plays double note

Post by garranimal » Wed Oct 12, 2016 7:36 pm

Swapping the voice chips tells you it's not the voice chip. Have you re-calibrated anything?...after acetone bath I have found this necessary. Carefully check the power supply calibration under load as well, make sure there the DC output is within spec. Otherwise you'll have to trace the signals in voice 3 with a scope to see where it's going wrong.

ChuckFalcon
Newbie
Newbie
Posts: 57
Joined: Fri Jun 27, 2014 3:24 am
Real name: Chuck Falcon
Gear: Roland Promars MRS-2
Vox Continental
Mellotron M4000D
Roland Juno 60
Moog Theremini
Roland Juno 106
Akai MPC 1000
Band: Chuck Falcon

Re: HELP Roland Juno 106 3rd voice plays double note

Post by ChuckFalcon » Wed Oct 12, 2016 9:57 pm

garranimal wrote:Swapping the voice chips tells you it's not the voice chip. Have you re-calibrated anything?...after acetone bath I have found this necessary. Carefully check the power supply calibration under load as well, make sure there the DC output is within spec. Otherwise you'll have to trace the signals in voice 3 with a scope to see where it's going wrong.
Nah, I haven't calibrated anything yet. Before the acetone bath I had no square wave and I still had the 3rd note problem. I ended up destroying one of the wave chips because I thought I was supposed to take off the black goo underneath the casing of the wave chips. I bought a reproduction one to replace the one I destroyed, put all the chips back in and the square wave bounced back however its still just slightly quieter than the triangle wave.

I have been told that it is possibly a bad wave chip or a multiplexer chip. I have a scope but have never used it and don't know how to use it. I know the general area of where the problem is on the board. Since I'm newer to the scope, any chance you can tell me what connections I would need to make? Ground of scope > Ground of juno 106, and then just probe it? What am I looking for on the screen?

Mooger5
Expert Member
Expert Member
Posts: 1459
Joined: Tue May 06, 2008 5:11 pm
Location: Lisbon

Re: HELP Roland Juno 106 3rd voice plays double note

Post by Mooger5 » Wed Oct 12, 2016 10:25 pm

Voices 3 and 4 are generated by the same chip. Use a magnifying lens to detect any stray solder bridges.
Poly 2 always starts with voice 1. Press c1 and hold, then d1 and hold then c3. C3 will play voice 3. How does it sound? then press c4. C4 will be voice 4. How does it sound? Then lift c1 and d1 and and you´ll be left with voices 3 and 4. You can lift the keys. Provided no more keys are pressed, c3 and c4 will be assigned to their respective voices and you can play them at the same time or alternatively for comparision.
If there´s nothing wrong with the soldering, the problem is probably happening before the chip.
Herrare umanum est.

ChuckFalcon
Newbie
Newbie
Posts: 57
Joined: Fri Jun 27, 2014 3:24 am
Real name: Chuck Falcon
Gear: Roland Promars MRS-2
Vox Continental
Mellotron M4000D
Roland Juno 60
Moog Theremini
Roland Juno 106
Akai MPC 1000
Band: Chuck Falcon

Re: HELP Roland Juno 106 3rd voice plays double note

Post by ChuckFalcon » Thu Oct 13, 2016 3:42 pm

Mooger5 wrote:Voices 3 and 4 are generated by the same chip. Use a magnifying lens to detect any stray solder bridges.
Poly 2 always starts with voice 1. Press c1 and hold, then d1 and hold then c3. C3 will play voice 3. How does it sound? then press c4. C4 will be voice 4. How does it sound? Then lift c1 and d1 and and you´ll be left with voices 3 and 4. You can lift the keys. Provided no more keys are pressed, c3 and c4 will be assigned to their respective voices and you can play them at the same time or alternatively for comparision.
If there´s nothing wrong with the soldering, the problem is probably happening before the chip.
I did that test that you mentioned but things still sounded the same. when I played C3, it played C4 along with it. Since I didn't really know what to do with my oscilloscope I decided to swap wave chip 3/4 with wave chip 1/2 to see if the problem moved to voices 1 and 2. Welllllll........it moved. Soooooooo, I guess that means that I found my problem, the wave chip has gone bad. Looks like I gotta plunk down $50 for a new one :cry: :roll:

Anyways, I will order a new wave chip and let everyone know what happens. The plan is new chip, calibration of everything and then a new video. Thanks for all of the help so far.

Mooger5
Expert Member
Expert Member
Posts: 1459
Joined: Tue May 06, 2008 5:11 pm
Location: Lisbon

Re: HELP Roland Juno 106 3rd voice plays double note

Post by Mooger5 » Thu Oct 13, 2016 8:57 pm

So you did the acetone trick to the wave chips? If the "tar blobs" are still intact there´s a remote possibility chip could be saved. Pins 13, 14 are sub out and wave out of voice A, pins 15 and 16 are for sub and wave out of voice B. Notice how pins of those chips are too close to one another, a different pitch than usual. Inspect the offending chip closely and see if there´s something that´s causing a short between the voices as that´s what it sounds like. Hairline solder bridge, tiny bit of metal, dirt, solder paste, a scratch, whatever. Good luck.
Herrare umanum est.

ChuckFalcon
Newbie
Newbie
Posts: 57
Joined: Fri Jun 27, 2014 3:24 am
Real name: Chuck Falcon
Gear: Roland Promars MRS-2
Vox Continental
Mellotron M4000D
Roland Juno 60
Moog Theremini
Roland Juno 106
Akai MPC 1000
Band: Chuck Falcon

Re: HELP Roland Juno 106 3rd voice plays double note

Post by ChuckFalcon » Fri Oct 14, 2016 2:38 pm

Mooger5 wrote:So you did the acetone trick to the wave chips? If the "tar blobs" are still intact there´s a remote possibility chip could be saved. Pins 13, 14 are sub out and wave out of voice A, pins 15 and 16 are for sub and wave out of voice B. Notice how pins of those chips are too close to one another, a different pitch than usual. Inspect the offending chip closely and see if there´s something that´s causing a short between the voices as that´s what it sounds like. Hairline solder bridge, tiny bit of metal, dirt, solder paste, a scratch, whatever. Good luck.
AWESOME! Thanks for the tip. I'll check it out. Last night my last filter on my motorized desoldering finally bit the dust. I ordered some new filters last night. Now I wait :roll:

ChuckFalcon
Newbie
Newbie
Posts: 57
Joined: Fri Jun 27, 2014 3:24 am
Real name: Chuck Falcon
Gear: Roland Promars MRS-2
Vox Continental
Mellotron M4000D
Roland Juno 60
Moog Theremini
Roland Juno 106
Akai MPC 1000
Band: Chuck Falcon

Re: HELP Roland Juno 106 3rd voice plays double note

Post by ChuckFalcon » Mon Oct 24, 2016 8:58 pm

Mooger5 wrote:So you did the acetone trick to the wave chips? If the "tar blobs" are still intact there´s a remote possibility chip could be saved. Pins 13, 14 are sub out and wave out of voice A, pins 15 and 16 are for sub and wave out of voice B. Notice how pins of those chips are too close to one another, a different pitch than usual. Inspect the offending chip closely and see if there´s something that´s causing a short between the voices as that´s what it sounds like. Hairline solder bridge, tiny bit of metal, dirt, solder paste, a scratch, whatever. Good luck.

UPDATE!!! No more voice doubling. I put in the new wave chip and bingo! I replaced the battery on friday then got super bummed when I lost all my presets THEN I had a friend show me how easy it was to add them all back.

HOWEVER......a new (or just noticed) problem has showed itself. No white noise. I guess I never noticed because I never used it. However, I would like to get it fixed. So far this is what I know

-The actual fader goes up and down in value
-When the synth is on, connected to my PA and in test mode and the key "hold" function is on, I hear white noise when I touch my audio to the junction of Pin 1 of IC14 and TR22. I hear the white noise through the Juno's output, not the audio probe's output. This same exact thing happened when I was using my oscilloscope probe instead of my audio probe.
-When I am making the white noise happen, and move the VCF faders, the white noise is being filtered like its supposed to.

I hope all that makes sense. Any idea of what is going on?

Mooger5
Expert Member
Expert Member
Posts: 1459
Joined: Tue May 06, 2008 5:11 pm
Location: Lisbon

Re: HELP Roland Juno 106 3rd voice plays double note

Post by Mooger5 » Tue Oct 25, 2016 10:28 pm

There is a trimmer, vr32 for calibrating the noise level. See if it changes anything.
Test tr22 with a multimeter. No need to desolder as it is not in paralel to anything.
Herrare umanum est.

ChuckFalcon
Newbie
Newbie
Posts: 57
Joined: Fri Jun 27, 2014 3:24 am
Real name: Chuck Falcon
Gear: Roland Promars MRS-2
Vox Continental
Mellotron M4000D
Roland Juno 60
Moog Theremini
Roland Juno 106
Akai MPC 1000
Band: Chuck Falcon

Re: HELP Roland Juno 106 3rd voice plays double note

Post by ChuckFalcon » Wed Oct 26, 2016 7:30 pm

Mooger5 wrote:There is a trimmer, vr32 for calibrating the noise level. See if it changes anything.
Test tr22 with a multimeter. No need to desolder as it is not in paralel to anything.
No changes at all when I turn VR32. I ended up taking TR22 out of the board and tested it it for shorts with my DCA55 and it checks out good with no shorts. Any other ideas? I decided to take VR32 out to see if it works, and it still does too. This synth is officially making me crazy, lol

ChuckFalcon
Newbie
Newbie
Posts: 57
Joined: Fri Jun 27, 2014 3:24 am
Real name: Chuck Falcon
Gear: Roland Promars MRS-2
Vox Continental
Mellotron M4000D
Roland Juno 60
Moog Theremini
Roland Juno 106
Akai MPC 1000
Band: Chuck Falcon

Re: HELP Roland Juno 106 3rd voice plays double note

Post by ChuckFalcon » Wed Oct 26, 2016 8:04 pm

ChuckFalcon wrote:
Mooger5 wrote:There is a trimmer, vr32 for calibrating the noise level. See if it changes anything.
Test tr22 with a multimeter. No need to desolder as it is not in paralel to anything.
No changes at all when I turn VR32. I ended up taking TR22 out of the board and tested it it for shorts with my DCA55 and it checks out good with no shorts. Any other ideas? I decided to take VR32 out to see if it works, and it still does too. This synth is officially making me crazy, lol
Ok, I did some more test. The 106 can be in manual mode or any preset mode and I can ONLY get the noise to fire if touch my probe to the junction of Pin 1 of IC14 and TR22. When I hold the probe that area and then press a key the noise will fire. VR32 seem to be doing nothing. The noise fader also seems to be doing nothing.

If the probe is not plugged into a PA channel, the noise will not fire (I have the probe's audio turned completely silent). The white noise that is being heard is coming from the Juno 106's output.

Mooger5
Expert Member
Expert Member
Posts: 1459
Joined: Tue May 06, 2008 5:11 pm
Location: Lisbon

Re: HELP Roland Juno 106 3rd voice plays double note

Post by Mooger5 » Thu Oct 27, 2016 6:52 am

ic14 is a vca. the control current goes from tr22 to pin1, so it´s probable ic14 is ok. if tr22 and vr32 are ok there´s a chance the vca is not getting the control current. I don´t have the service notes here atm, but there are 2 chips before vr32, a 4051 and an opamp. follow the path and check for a change in the signal while moving the noise slider at the same time. later
Herrare umanum est.

ChuckFalcon
Newbie
Newbie
Posts: 57
Joined: Fri Jun 27, 2014 3:24 am
Real name: Chuck Falcon
Gear: Roland Promars MRS-2
Vox Continental
Mellotron M4000D
Roland Juno 60
Moog Theremini
Roland Juno 106
Akai MPC 1000
Band: Chuck Falcon

Re: HELP Roland Juno 106 3rd voice plays double note

Post by ChuckFalcon » Thu Oct 27, 2016 7:45 pm

Mooger5 wrote:ic14 is a vca. the control current goes from tr22 to pin1, so it´s probable ic14 is ok. if tr22 and vr32 are ok there´s a chance the vca is not getting the control current. I don´t have the service notes here atm, but there are 2 chips before vr32, a 4051 and an opamp. follow the path and check for a change in the signal while moving the noise slider at the same time. later
YOU NAILED IT!!!!!! IC26 wasn't making good connection to its solder pad. I gave it some fresh solder and now I got the noise!!!!! Thank you so so SO much. I am currently looking at a 100% operational Roland Juno 106. Really thank you so much! I am finally getting to where I can understand a block diagram!

Mooger5
Expert Member
Expert Member
Posts: 1459
Joined: Tue May 06, 2008 5:11 pm
Location: Lisbon

Re: HELP Roland Juno 106 3rd voice plays double note

Post by Mooger5 » Fri Oct 28, 2016 6:34 am

No problem. Glad to know another Juno got fixed. And being able to read a schematic so you can start fixing things on your own is very rewarding and an education.
Cheers!
Herrare umanum est.

Post Reply