Juno-106 filter problem

[Shayne White]

For anyone who owns and knows about the Roland Juno-106 keyboard (off of which UKnow 007 was based), I'm having a little trouble with mine. I bought one a few months ago from Ebay, and while all six voice chips seem to be work, voice 6's VCF is considerably brighter than the other voices. But only sometimes. Sometimes it all sounds normal, other times it's much brighter. I'm not sure if this is a sign that voice 6 is about to go dead, since that is a common issue with the old 106's. It still produces a sound, it's just a little unpredictable.

It loaded it up in diagnostic mode and determined that it is voice 6 that is acting strangely.

Thanks in advance,

Shayne

[Mr Arkadin]

To be honest i would have avoided a 106 given the legendary status of the voice chips - although i thought it was just the VCA that died - not the filter? Anyway, you may very well have a Juno 105 before long.

[dawman]

I never opened one up, but the Oberheims each had voice cards where brightness per voice via VCF, and tuning per voice via VCO could be tweaked. They often would go off on their own w/o any adjustments.
I just recently broke out the OBX and watched the auto tune do it's job, only to be out after the first hour of use.
For the 29 years I have owned the Oberheims and other analogs, I never have the screws in the lid, because I always needed to tweak the filters & tunings.

Good Luck.

[netguyjoel]

ask kurt

http://www.kurtsamps.com/kurtsynth1.html

He did an OBXa for a friend of mine & he can pretty much repair most anything

[Fluxpod]

You could also buy these replacement chips.http://www.analoguerenaissance.com/D80017/

[Shayne White]

It's probably the case that it's just a factor of unstable analog components that aren't calibrated the same. If it ever dies for real I'll get replacement chips.

I bought the 106 because a) it's vintage 80's, b) it's analog, c) it was under $500, and d) OMG that chorus!!!!

Thanks for your help,

Shayne

[dawman]

For analog one should use analog...................

[Mr Arkadin]

i prefer my Jupiter 4 for the Roland sound

[capacitor]

Shane, thanks for the Band Phase. Great stuff

This doesn't help directly, but - I've had exactly the same problem with voice 5 (of six) on a Crumar/Unique Systems DBE/Bit01. The solution was to clean & reseat the socketed filter chip (CEM 3328 14 pin DIP).

I looked at Fluxpod's link & it looks like the filter IC is soldered directly in. Does the problem goe away when (gently) moving the chip for that voice?

If so, it might be fixable by a careful resoldering of the pins. Low-ish heat setting with a really small alligator clip to draw off the excess heat. That's what I'm thinking anyhow. It might be a bad internal connection too, so moving the chip works, but reflowing the solder doesn't..

In my case, this problem was there from day 1 - bad contact with two of the legs of the IC, which controlled Freq & Q - it was nasty

Hope This Helps.

Best regards,
-cap

[astroman]

i prefer my Jupiter 4 for the Roland sound

looks like you're not the only one...
can't remember the last time I spotted one on eBay

Shane you might consider collecting a few spares as long as they are relatively affordable.
Prices are constantly on the rise for CEM stuff (I assume it's CEM inside...)
A pro dealer here charges 99 Euro per chip

cheers, Tom

[capacitor]

It actually is a custom Roland module, which does both the filter & VCA (from the article, it's the amp part that usually goes south):

[dawman]

I would love for Holger to take the old 3300 series used on Oberheims and glue them to the XITE-1 PCB !!!!

[kylie]

I would love for Holger to take the old 3300 series used on Oberheims and glue them to the XITE-1 PCB !!!!

the xite-1 pcb is final, so you would not benefit from it. except you buy an upgrade kit that fits to a mysterious connector hidden somewhere on the board...

[Shayne White]

Thanks, I should probably take it apart and see what's inside, although I don't think I'd really want to touch anything. If it gets too annoying I'll have a keyboard technician look at it. For all I know, the VCF/VCA chips have already all been replaced already.

Shayne

[Mr Arkadin]

A pro dealer here charges 99 Euro per chip

By the time you've got six chips you could just get a whole 106 .

[Shroomz~>]

A pro dealer here charges 99 Euro per chip

By the time you've got six chips you could just get a whole 106 .

Or a whole Juno-60.

[Shayne White]

Juno-60 doesn't have MIDI.

[dawman]

Shayne, there's a great synth tech at Skip's Music in Sacramento, well he was there a few years ago. It's not too far from you, and if he is gone, it's because he opened his own business. He knows his stuff really well, and ain't too far from the 101.

[Shroomz~>]

Juno-60 doesn't have MIDI.

It does if you plug it into one of these. 160 EU for some serious midi action. Look at the specs.