Jupiter 6 - Master Tuning issue

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Jupiter 6 - Master Tuning issue

Postby WhinyLittleRunt » Sun Mar 27, 2016 5:26 am

More important than the CP30, for sure. My recently-acquired Jupiter 6 w/ Europa is having a tuning problem which is making the synth somewhat unusable in a standard way. I cannot, for the life of me, get the tuning to A440 using the master tune knob. At dead center it is sharp by almost a whole note, and all the way to the left (flat) it is just about in tune but still sharp and noticeable. I'm guessing it's a hardware problem at this point but I wanted to check with you guys and make sure it's not just a problem with the Europa mod... I've already sent Jeff @ Synthcom a few messages regarding the issue and he's gotten back to me each time with instruction, mainly about setting the proper transpose. This unfortunately made no difference. It isn't an oscillator that is drifting out of tune, it's the whole keyboard and the master tuning knob that everything is sharp by a note if kept at dead center. There isn't much flexibility in the master tune knob either. Has anyone encountered this issue? I've seen it talked about on the webs but there is really not much talked about when it comes to master tuning... this isn't like an oscillator or 2 are drifting out, it's the whole master tune is off-kilter.

Also, my Europa may be working incorrectly, because if I boot into the Roland code, it pretty much just crashes.

Anyway, as always, if anyone has any suggestions...
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Re: Jupiter 6 - Master Tuning issue

Postby WhinyLittleRunt » Sun Mar 27, 2016 9:27 pm

I just opened it up to see about checking the measurements outlined in the Calibration procedure from the service manual, and I measured the DC Offset which is supposed to be set to 0V, and my measurement between the points is actually showing 2.5v... Could it really be off by that much? I don't even want to adjust that yet until I know since I wouldn't even think the trimmer would go that far...
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Re: Jupiter 6 - Master Tuning issue

Postby micahjonhughes » Mon Mar 28, 2016 10:52 pm

I guess I would back up a page and first be sure that the power supply is putting out the correct voltages. Also, you probably want to check and see if the voltages are changing as the synth warms up.
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Re: Jupiter 6 - Master Tuning issue

Postby synthroom » Tue Mar 29, 2016 4:14 am

Could it be an issue with the pitch bender?
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Re: Jupiter 6 - Master Tuning issue

Postby synthparts » Wed Mar 30, 2016 1:35 am

synthroom wrote:Could it be an issue with the pitch bender?


Yes, an easy way to test this is go to a Split patch and turn off the bender for one side and see if the pitch changes.
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Re: Jupiter 6 - Master Tuning issue

Postby WhinyLittleRunt » Wed Mar 30, 2016 3:36 am

micahjonhughes wrote:I guess I would back up a page and first be sure that the power supply is putting out the correct voltages. Also, you probably want to check and see if the voltages are changing as the synth warms up.


I adjusted the supply voltages in the calibration procedure to hit the correct numbers (10, 5 etc) they weren't even off by a mv...

I just got a little apprehensive with the d/a offset being off by so much I don't feel like that trimmer can bring it back to 0v but I didn't try it yet. I automatically assumed it would be a component elsewhere...

synthparts wrote:
synthroom wrote:Could it be an issue with the pitch bender?


Yes, an easy way to test this is go to a Split patch and turn off the bender for one side and see if the pitch changes.


And yes, this does change the pitch. Here's a video to show- remember, this is a Europa machine so most of this was done for Synthcom to look and see if it was related in any way to that before deeming it a hardware issue...

Watch on youtube.com
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Re: Jupiter 6 - Master Tuning issue

Postby synthparts » Wed Mar 30, 2016 4:07 am

WhinyLittleRunt wrote:
synthparts wrote:
synthroom wrote:Could it be an issue with the pitch bender?


Yes, an easy way to test this is go to a Split patch and turn off the bender for one side and see if the pitch changes.


And yes, this does change the pitch. Here's a video to show- remember, this is a Europa machine so most of this was done for Synthcom to look and see if it was related in any way to that before deeming it a hardware issue...



OK if the pitch changes by just activating the bender section (not moving the bender) then the bender pot needs to be calibrated/adjusted (VR1 & VR2 trimpots on the bender board).
Last edited by synthparts on Wed Mar 30, 2016 4:21 am, edited 1 time in total.
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Re: Jupiter 6 - Master Tuning issue

Postby WhinyLittleRunt » Wed Mar 30, 2016 4:18 am

synthparts wrote:OK if the pitch changes by just activating the bender section (not moving the bender) then the bender pot needs to be calibrated/adjusted.


Cool - I actually skipped over most of the calibration procedure and went right to that after looking at the D.A Offset but again, my scope wasn't showing me what I was 'expecting' to find so I left it alone. Sounds like I have some simple yet time consuming work ahead of me. Glad to know it's probably just an adjustment.
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Re: Jupiter 6 - Master Tuning issue

Postby synthparts » Wed Mar 30, 2016 4:22 am

WhinyLittleRunt wrote:
synthparts wrote:OK if the pitch changes by just activating the bender section (not moving the bender) then the bender pot needs to be calibrated/adjusted.


Cool - I actually skipped over most of the calibration procedure and went right to that after looking at the D.A Offset but again, my scope wasn't showing me what I was 'expecting' to find so I left it alone. Sounds like I have some simple yet time consuming work ahead of me. Glad to know it's probably just an adjustment.


It should be real simple. Just adjust VR1 (VCO1) and VR2 (VCO2) on the bender board. Hopefully you didn't mess around with the D/A Offset adjustment too much...
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Re: Jupiter 6 - Master Tuning issue

Postby WhinyLittleRunt » Wed Mar 30, 2016 4:37 am

synthparts wrote:It should be real simple. Just adjust VR1 (VCO1) and VR2 (VCO2) on the bender board. Hopefully you didn't mess around with the D/A Offset adjustment too much...


Nope, I didn't touch it more than a smidge when I saw it wasn't moving much / not enough range to possibly bring it back to 0v, so I left it alone.

I know about the VR and VR2 adjustment pots, but the adjustment notes say you need a scope to line it all up; are you saying 'just adjust' loosely and mean with the scope or just on the fly?
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Re: Jupiter 6 - Master Tuning issue

Postby synthparts » Wed Mar 30, 2016 4:52 am

WhinyLittleRunt wrote:
synthparts wrote:It should be real simple. Just adjust VR1 (VCO1) and VR2 (VCO2) on the bender board. Hopefully you didn't mess around with the D/A Offset adjustment too much...


Nope, I didn't touch it more than a smidge when I saw it wasn't moving much / not enough range to possibly bring it back to 0v, so I left it alone.

I know about the VR and VR2 adjustment pots, but the adjustment notes say you need a scope to line it all up; are you saying 'just adjust' loosely and mean with the scope or just on the fly?


Just adjust the 2 trimpots on the topside of the bender board by ear so that there's no pitch change when you activate the bender section...
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Re: Jupiter 6 - Master Tuning issue

Postby WhinyLittleRunt » Wed Mar 30, 2016 5:01 am

Oh damn... if it was that easy I should have done that the other day. lol, thanks man - I'll report back.
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Re: Jupiter 6 - Master Tuning issue

Postby WhinyLittleRunt » Thu Mar 31, 2016 1:14 am

I think I got it to a happy point; took a lot of back and forth tweaking but I think I'm in tune properly now after adjusting the bender board trimpots. But there are still some weird things happening, like when you open and close the lid sometimes the pitch changes, so I tried isolating that to the group of cables that run along the left side from the bender board back to the outputs etc. I'm not sure if that was a fluke or what, but it definitely was happening. Also, I did try adjusting the D/A Offset on both boards, and they're both hovering around 3.7v now. That ain't right. But on both boards? What is the common denominator? I see in the service manual that they feed off IC12 but it's just not right to me that we have two failed chips in the identical place on different boards. Something else is up. I know at one time this was in the hands of the Analog Lab and they did some work on it, possible that they changed out a bunch of caps because there are quite a few that look newer. I'm likely going to bring it back to them to look at eventually since they just did my OB-8. But all in all, right now it's working.
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Re: Jupiter 6 - Master Tuning issue

Postby V301H » Thu Mar 31, 2016 5:41 am

I have a similar problem with my Jupiter 6. It should be in tune when the tuning knob is in the middle but is actually in tune when the knob is about a quarter of the way up. I took it in to have Europa installed and asked the well-known "tech" to calibrate the tuning. He acted like it was no big deal and didn't fix it. Afterward I found the pitch was off on one side in split mode.
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Re: Jupiter 6 - Master Tuning issue

Postby WhinyLittleRunt » Thu Mar 31, 2016 5:57 pm

V301H wrote:I have a similar problem with my Jupiter 6. It should be in tune when the tuning knob is in the middle but is actually in tune when the knob is about a quarter of the way up. I took it in to have Europa installed and asked the well-known "tech" to calibrate the tuning. He acted like it was no big deal and didn't fix it. Afterward I found the pitch was off on one side in split mode.


Beat, you talking about the same place?
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