Need to Save This Juno 60! (Voice Issues + More)

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moogerfooger
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Need to Save This Juno 60! (Voice Issues + More)

Post by moogerfooger » Fri Mar 30, 2018 9:23 pm

Hey y'all.

Got a really solid deal on a Juno 60 online. But with this great deal came problems. This thing needs some TLC in a few departments. I tried to be as clear and concise as possible here, but please correct me if I'm wrong or jab me if I haven't provided enough info :D

The issues:

-Voice 3 is silent
-Voice 5 is REALLY LOUD
-In test mode, it won't access the test banks (8 +9). When I hold Bank 5 and press 3, it just goes to Bank 53. I followed the instructions from the service manual. I can access Bank 6 + 7 just fine. Let me know if I did something wrong! The seller online mentioned that there was an issue with 2 of the banks, though he wasn't sure specifically.
-LFO Trigger button does not function. That is not my main concern.

Some notes:

I put the Juno in test mode and dialed in (as best as I could) the program parameters to test the VCA levels with my scope. Voice 3 is silent, even when manipulating the VR for the gain. Voice 5 is still blaringly loud, and trimming the gain VR does nothing.

Every VCA chip EXCEPT Voice 5 is a BA662 clone from Open Labs. Voice 5 has an original Roland BA662 A. My initial thought is that the original chip is bad. But, Voice 3 contains a BA662 clone. I'm curious to see if that is the culprit for its silence, or if there is somewhere earlier in the circuit path where I should look.

The synth came to me without any of the presets in the banks. Pushing a new preset did not change the sound. I tried loading the factory patches in via the tape load but was unsuccessful. But, that's the least of my worries. My main focus is getting the voices to a consistent level.

Any help will be greatly appreciated!

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rhino
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Re: Need to Save This Juno 60! (Voice Issues + More)

Post by rhino » Fri Mar 30, 2018 11:10 pm

not much from afar:
I got a busted '60 sometime back, could not load all patches. Some would load ok, some would remain the same, a few would load, but weird.
corosion, or something had eated one pin off of one of the memory chips.
When the wise man points to the stars, the fool looks at the finger.
- Confucius

moogerfooger
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Re: Need to Save This Juno 60! (Voice Issues + More)

Post by moogerfooger » Mon Apr 02, 2018 5:24 pm

rhino wrote:not much from afar:
I got a busted '60 sometime back, could not load all patches. Some would load ok, some would remain the same, a few would load, but weird.
corosion, or something had eated one pin off of one of the memory chips.
Yea. I just checked if I could save patches. I can! So that's a good thing, I guess. I'm gonna attempt to send it the factory patches again today. I have to get the volume right from my computer.

I also just checked the Sawtooth via TP3 on each of the waveform chips. Voice 3 works just fine, and looks exactly like all the other waveforms. Voice 5 looks fine at that stage as well.

So, I think i'm going to replace the two BA662 ICs that are troubling, and see what happens from there.

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