While calibrating my Juno 106 I noticed

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.
Steve Jones
Active Member
Active Member
Posts: 565
Joined: Wed Apr 23, 2008 10:40 pm
Real name: Steve
Location: Sydney
Contact:

Re: While calibrating my Juno 106 I noticed

Post by Steve Jones » Fri Mar 01, 2013 12:06 pm

Switching a scope's voltage range doesn't change anything other than the visible size of the displayed waveform. If you have the scope set to 1V then each grid line equals one volt on the waveform, if you switch it to 3V per division then the size of the waveform on the screen shrinks but each grid line equals 3 volts. The voltage range switching on an oscilloscope is there purely to allow you to make the displayed waveform fit the screen nicely. for example, if you have a sine wave displayed and it is 6 grid lines from the top of the waveform image to the bottom of the waveform image when the scope is set to 1V then the voltage of the waveform is 6V peak-to-peak. If you switch the scope to 3V per division the displayed waveform will shrink so that it is only fills 2 divisions, but you can still see that the voltage is exactly the same - 6V peak to peak as each grid line represents 3 Volts.
Synthesizer service tech since 1982.
Synth parts and service, Sydney Australia.

KennaOkoye
Newbie
Newbie
Posts: 73
Joined: Thu Nov 17, 2011 12:44 am
Real name: Kenna
Gear: Yamaha PSS-370, Roland Juno 106, Roland D50, Fender Stratocaster Deluxe Fat Strat
Location: New York

Re: While calibrating my Juno 106 I noticed

Post by KennaOkoye » Fri Mar 01, 2013 12:09 pm

ok yeah i get what you are saying...thanks! when i switch it will go from something like 6vPP to 6.08vPP i guess thats not much

themilford
Senior Member
Senior Member
Posts: 819
Joined: Sun Jan 10, 2010 1:19 am
Real name: David
Gear: Oberheim SYSTEM: OB8, DSX, DMX, DXa, Moog Taurus 3, Fender Bass IV LH (CS), Rickenbacker 620/6 (LH), Crumar Trilogy needing major repair.
Band: Season Finale
Location: Brooklyn, NY
Contact:

Re: While calibrating my Juno 106 I noticed

Post by themilford » Fri Mar 01, 2013 2:15 pm

Just an quick educational note:

VR is probably Roland's (and others') shortening for "Variable resistor" which is often used interchangeably with "Potentiometer"... even though it is a specific term itself.

For short, folks use the term "pot" for potentiometer... and "trimmer" or "trim pot" usually refers to a smaller potentiometer PCB mounted pot intended for an instrument's calibration adjustment usually for a service technician and not the end-user. Usually designed for screwdriver trimmer tool adjustment.

these are handy to have around
Image

KennaOkoye
Newbie
Newbie
Posts: 73
Joined: Thu Nov 17, 2011 12:44 am
Real name: Kenna
Gear: Yamaha PSS-370, Roland Juno 106, Roland D50, Fender Stratocaster Deluxe Fat Strat
Location: New York

Re: While calibrating my Juno 106 I noticed

Post by KennaOkoye » Mon Mar 04, 2013 8:33 am

steve jones how did you perform step 9? i turned vr32 until it couldnt turn anymore... how do I get to 4v pp? is that even possible with noise???

KennaOkoye
Newbie
Newbie
Posts: 73
Joined: Thu Nov 17, 2011 12:44 am
Real name: Kenna
Gear: Yamaha PSS-370, Roland Juno 106, Roland D50, Fender Stratocaster Deluxe Fat Strat
Location: New York

Re: While calibrating my Juno 106 I noticed

Post by KennaOkoye » Mon Mar 04, 2013 10:41 am

Done, the weird chorus 2 beating is gone!!!! so happy right now! :D

Any tip for anyone doing this... Use a screw driver, it has less throw than the thing they give you with an oscilloscope...it was a nightmare using that little screw thing... i kept going back and forth over the intended numbers... REPEAT steps 6-8... still confused about steps 9 NOISE osc. I just got it as close as I can in the picture.

I paid 160 dollars to Three Wave Music to do a load offset, alot easier and cheaper even if you factor in a decent Radio Shack multimeter. Thanks for everyone that put their two cents. Really appreciate it

JHatzia
Junior Member
Junior Member
Posts: 121
Joined: Sun Jun 10, 2012 8:05 pm

Re: While calibrating my Juno 106 I noticed

Post by JHatzia » Sun Jun 29, 2014 7:47 pm

Hey I have an early Juno 106 with these test points as well. Currently I am calibrating mine with a DSO Nano V3 oscope. When doing step 5 in the 106 calibration section in the service manual I am having a really hard time getting a peak to peak signal coming from these test points. The manual says to connect to the hot terminal of the trimmer for connection but I am only seeing slight noise on my oscope, no sinewave at all. I've searched all over the web it this topic is one of very few that covers this.

Please help me out

kirkwood
Supporting Member!
Supporting Member!
Posts: 9
Joined: Tue Jul 10, 2012 4:55 pm
Gear: Roland Jupiter-6
Roland Juno-106
Roland SH-101
Ensoniq ESQ1
Elektron Machinedrum
Elektron Monomachine
Elektron Octatrack
Yamaha TX7

Re: While calibrating my Juno 106 I noticed

Post by kirkwood » Sat Jul 30, 2016 9:28 pm

JHatzia wrote:Hey I have an early Juno 106 with these test points as well. Currently I am calibrating mine with a DSO Nano V3 oscope. When doing step 5 in the 106 calibration section in the service manual I am having a really hard time getting a peak to peak signal coming from these test points. The manual says to connect to the hot terminal of the trimmer for connection but I am only seeing slight noise on my oscope, no sinewave at all. I've searched all over the web it this topic is one of very few that covers this.

Please help me out
Running into this same issue as you. did you come up with a solution?

kirkwood
Supporting Member!
Supporting Member!
Posts: 9
Joined: Tue Jul 10, 2012 4:55 pm
Gear: Roland Jupiter-6
Roland Juno-106
Roland SH-101
Ensoniq ESQ1
Elektron Machinedrum
Elektron Monomachine
Elektron Octatrack
Yamaha TX7

Re: While calibrating my Juno 106 I noticed

Post by kirkwood » Sun Jul 31, 2016 11:37 pm

figured it out...
JHatzia wrote:Hey I have an early Juno 106 with these test points as well. Currently I am calibrating mine with a DSO Nano V3 oscope. When doing step 5 in the 106 calibration section in the service manual I am having a really hard time getting a peak to peak signal coming from these test points. The manual says to connect to the hot terminal of the trimmer for connection but I am only seeing slight noise on my oscope, no sinewave at all. I've searched all over the web it this topic is one of very few that covers this.

Please help me out
For calibration Step step 5, the adjustments are done on VR NO. 26, 21, 16, 11, 6, 1.
The oscilloscope test point is set on the hot terminal of VR NO. 27, 22, 17, 12, 7, 2.

I had to do a double take on this video but it shows what to do...

Post Reply