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Monstruarte
Joined: Sep 25, 2009 Posts: 73 Location: Argentina
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Posted: Tue Feb 09, 2010 6:30 am Post subject:
sequecer problem... |
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I just finished the construction of a 16-step Sequencer I have only one problem:
1 - The most important of all.
No sound. Voltage outs from the sequencer go to OSC 1 & 2 CV in jacks on Soundlab, gate out from the sequencer goes to gate in on the Soundlab. When I connect it, the sound is off.
In my field of vision all goes well, all leds work, start, stop, reverse, but still no sound.
Any suggestions? |
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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Posted: Tue Feb 09, 2010 9:26 am Post subject:
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The Soundlab made sound before you plugged the sequencer in?
Just checking
Perhaps the sequencer output is too high - turn the pots down a bit....
bruce _________________ www.sdiy.org/rfeng
"I want to make these sounds that go wooo-wooo-ah-woo-woo.”
(Herb Deutsch to Bob Moog ~1963) |
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Monstruarte
Joined: Sep 25, 2009 Posts: 73 Location: Argentina
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Posted: Tue Feb 09, 2010 11:12 am Post subject:
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The Soundlab made sound before I connect the Sequencer. After connecting, the sound is off.
I tried to turn the pots down a bit, but nothing happened. |
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Monstruarte
Joined: Sep 25, 2009 Posts: 73 Location: Argentina
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Posted: Tue Feb 09, 2010 7:28 pm Post subject:
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please at least some clue... |
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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Posted: Tue Feb 09, 2010 7:40 pm Post subject:
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Start from the beginning...
Turn Soundlab ON and adjust it so you hear a sound.
Turn Sequencer on - set it so it is not stepping - so it is stopped on 1 of the steps.
Put a voltmeter on the output of the sequencer and see if there is voltage.
Adjust the course tune pot on the sequencer and make sure the voltage goes up and down as you turn the pot.
Plug the sequencer into the CV input on the Soundlab.
Adjust the same sequencer pot and see if you can hear sound from the soundlab increasing and decreasing in pitch as you turn the sequencer course tune pot.
If you can, manually step the sequencer and adjust each pot in turn until you hear a tone from the soundlab. Repeat to verify all 16 steps are OK and can be tuned.
Start the sequencer.
If all is good - then we'll worry about the gate/trigger part...
good luck!
bruce _________________ www.sdiy.org/rfeng
"I want to make these sounds that go wooo-wooo-ah-woo-woo.”
(Herb Deutsch to Bob Moog ~1963) |
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Monstruarte
Joined: Sep 25, 2009 Posts: 73 Location: Argentina
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Posted: Wed Feb 10, 2010 6:54 am Post subject:
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thanks bruce, I'll try ... |
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Monstruarte
Joined: Sep 25, 2009 Posts: 73 Location: Argentina
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Posted: Wed Feb 10, 2010 12:11 pm Post subject:
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ok, I turn on the seq ... and testing the output of CV, the value moves between -17.15 and -17.30, when turning the pots these values do not change. neither up nor down. I have no idea of the problem. |
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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Posted: Wed Feb 10, 2010 12:44 pm Post subject:
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OK - Well...This isn't good
...but I'm sure we can get it figured out.
The output from the Sequencer should be between zero and around 10 volts, I think... Somewhere in that area depending on your power supply. What type of power supply are you using, by the way?
Measure the voltage from Ground to the CV output again - with the sequencer stopped, and you tweaking the course knob that is active (as indicated by the associated LED.
If it's not a positive voltage, and it doesn't adjust --- check your pot wiring, jack wiring, Gate sw and LED wiring...and the wiring and circuit around U1A - the TL084 on the Analog board.
That's a place to start, anyway...
good luck!
bruce _________________ www.sdiy.org/rfeng
"I want to make these sounds that go wooo-wooo-ah-woo-woo.”
(Herb Deutsch to Bob Moog ~1963) |
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Monstruarte
Joined: Sep 25, 2009 Posts: 73 Location: Argentina
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Posted: Wed Feb 10, 2010 1:44 pm Post subject:
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I'm using two multi power supply, one in-12v and the other in +12 v.
this is just an example.
Sequencer is stopped, the voltage of the active pot is: -17.50
I connected the positive test to + of the jack-CV- and the negative test to negative track in the analog board.
Also check the connections between the pots, leds, U1A and about, it's all good.
a fact ... when I turned on the sequencer for the first time, the electrolytic capacitor C3 exploded due to a short circuit was caused by bad cable connection on one side of the plate analog.
The tracks from the back of the plates made with wire, because I could not do double-sided plates.
in the first picture show you the error of the short. however, was repaired by replacing the capacitor C3 that had exploded. is likely that something else is burned?
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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Posted: Wed Feb 10, 2010 3:53 pm Post subject:
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Monstruarte wrote: | ... when I turned on the sequencer for the first time, the electrolytic capacitor C3 exploded... |
That's troubling. It sounds as if the Digital board is working fine though...so that's good.
Check U1 and U3 on the analog board... if it's not one of those, I wonder if the CD4067 is bad - and just running the negative supply voltage right to the I/O pin? .... I'll take a better look at the circuit a bit later and get back to you if I have any other thoughts.
For now - get the voltmeter and check for positive voltage at pin 2 and 7 of U3, and pins 5 and 7 of U1. Or maybe just swap out U1 and U3 _IF_ pin 2 on U3 is positive (and you have spares and used sockets on the board).
You can fix this - keep a positive attitude and step away from it if you are getting frustrated... Go back to it fresh later.
Something else - though I know you don't want to think about it now...
I might rethink your power supply... Those are un-regulated supplies - and they are supplying at least -17 volts (as you measured) - where you really want a solid, regulated + and - 12 volt supply....
Good Luck!
bruce _________________ www.sdiy.org/rfeng
"I want to make these sounds that go wooo-wooo-ah-woo-woo.”
(Herb Deutsch to Bob Moog ~1963) |
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Monstruarte
Joined: Sep 25, 2009 Posts: 73 Location: Argentina
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Posted: Thu Feb 11, 2010 7:35 pm Post subject:
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ok, the values are a little strange, the TL082 U3 is +17.40 V, and TL084 U1 has - 0.07v.
thanks for the peaceful advice were needed. |
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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Posted: Thu Feb 11, 2010 9:07 pm Post subject:
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Monstruarte wrote: | the TL082 U3 is +17.40 V, and TL084 U1 has - 0.07v. |
A little more specific please.. Which pins had those voltages?
bruce _________________ www.sdiy.org/rfeng
"I want to make these sounds that go wooo-wooo-ah-woo-woo.”
(Herb Deutsch to Bob Moog ~1963) |
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Monstruarte
Joined: Sep 25, 2009 Posts: 73 Location: Argentina
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Posted: Fri Feb 12, 2010 4:54 am Post subject:
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between pins 5 and 7 of TL084 U1 have -0.07v
between pins 2 and 7 of TL082 U3 have +17.40v
these are the pins you told me that I measured ... are the same to mark on the graphic above. this okay?
and forgive me for my robotic English, I am using a translator ... |
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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Posted: Fri Feb 12, 2010 6:25 am Post subject:
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There might be some confusion in translation -but we'll get through it.
Quick question...
Have you verified your power supply is still working right?
Measure from Ground to Positive, and then measure from Ground to Negative output.
Does the power supply look OK?
If so, we'll go back to what I was asking for in the earlier post. You need to measure the voltage from Ground to the specific pins I mentioned.
What I'm hoping to know is what voltage is going in, and what is coming out of those op-amps.
If you measure with the positive meter probe at Pin 2 of U3 and the negative probe at Ground, we can see what voltage is coming out of the CD4067 (U2) and maybe determine if the 4067 is the problem.
If you measure with the positive meter probe at Pin 7 of U3 and the negative probe at Ground, we can see if what's coming out of U3 - and perhaps determine if that chip is bad.... compare what's coming out, compared to what is going in...
Do the same with U1 - compare what's going in with what's coming out...
How does that look?
bruce _________________ www.sdiy.org/rfeng
"I want to make these sounds that go wooo-wooo-ah-woo-woo.”
(Herb Deutsch to Bob Moog ~1963) |
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Monstruarte
Joined: Sep 25, 2009 Posts: 73 Location: Argentina
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Posted: Tue Feb 16, 2010 7:06 pm Post subject:
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ok. I hope that this translator works.
I change the U3, reviewing the pin 2 whit the tester, I found that was not giving any voltage.
Anyway, change and U1. just in case. Although this gave good input and output voltage.
Also check the voltage of positive and negative output of the multi power supply, the strange thing was that Although they were put in 12v, marked 17v. so I put them in a lower voltage value, 7.5V, there marked 12v, subtly swinging Because they are not regulated. but they are useful to test the seq.
The good news is that now sounds. the problem is that is just a note, the pitch can not be changed. is only a very low note. oscillator level of sound lab, is totally high, like the pitch. otherwise this bass note, broken, and there are only isolated pulses.
The pitch can not be changed at any step of seq. in fact, this single bass note sounds when the knobs are at their lowest. or 0. CV output mark-10.00v at the sound this bass note. If I increase the level of pitch knobs in seq, the voltage changes to +10.50 v quickly and almost nonstop. The strange thing is that this voltage is the same that is in the pin 7 of U3 and 5 and 7 of U1.
In addition, on-off switches of the steps seem to go wrong.
Everything else works fine, visually speaking. all the LEDs move according to what I modify.
I'm completely lost.
Any ideas? |
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Monstruarte
Joined: Sep 25, 2009 Posts: 73 Location: Argentina
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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Posted: Wed Feb 17, 2010 4:38 pm Post subject:
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ooops - Didn't see you had responded... Sorry.
I'm on the way out the door - I get to play guitar tonight
I'll read over what you sent in detail when I get back in a few hours....
For now, really carefully check all the wiring to the pots and switches again....
bruce _________________ www.sdiy.org/rfeng
"I want to make these sounds that go wooo-wooo-ah-woo-woo.”
(Herb Deutsch to Bob Moog ~1963) |
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Monstruarte
Joined: Sep 25, 2009 Posts: 73 Location: Argentina
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Posted: Wed Feb 17, 2010 4:50 pm Post subject:
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ok, thank you very much bruce ... I really appreciate your help ...
and good luck with the show. |
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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Posted: Wed Feb 17, 2010 10:04 pm Post subject:
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OK- sorry for the delay...
I assume you have double checked all the potentiometer and switch wires?
Most problems are usually found in the 'flying wires' to the post and switches...
Check for supply voltages on the the positive and negative power pins on all the IC's on the analog board. Measure for + and - voltages compared to the Ground.
If all the voltages are OK...
We will start at the Course tune pot and work our way through the circuit. There is not much here, so it should not be hard to find where the problem is.
If you have IC U3 in a socket, pull it out.
Power the sequencer and Manually step it to Step One.
Measure the voltage at the center solder lug of R63 (the course tune pot for the step one)
(negative probe on Ground, positive probe on center lug of the pot)
Does the voltage change smoothly when you adjust the knob?
Measure the voltage on Pin 9 of the CD4067.
(negative probe on Ground, positive probe on pin 9 of the IC)
Does the voltage change smoothly when you adjust the knob?
Measure what voltage is on pin 2 of the socket for U3. (negative probe on Ground, positive probe on pin 2 of the socket)
Does the voltage change when you adjust the knob for the sequencers active step? Does it change nice and smooth?
If the voltages do what we expect to this point then we'll put U3 back in (power down first) and continue checking the in and out signal points of the IC's all the way to the output jacks....
OK?
Good Luck!
bruce _________________ www.sdiy.org/rfeng
"I want to make these sounds that go wooo-wooo-ah-woo-woo.”
(Herb Deutsch to Bob Moog ~1963) |
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Monstruarte
Joined: Sep 25, 2009 Posts: 73 Location: Argentina
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Posted: Thu Feb 18, 2010 9:09 am Post subject:
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RF wrote: |
If all the voltages are OK...
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ok, I follow the instructions... but...
which parameters to use when measuring the voltage? how do I know if the voltage is right or wrong? or if all the voltages is are ok?
and as always, thanks for the interest on the subject.
greetings |
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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Posted: Thu Feb 18, 2010 9:29 am Post subject:
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Look for the voltages to move smoothly up or down between (0 and 10 volts or so) when you turn the selected step's course tune potentiometer. _________________ www.sdiy.org/rfeng
"I want to make these sounds that go wooo-wooo-ah-woo-woo.”
(Herb Deutsch to Bob Moog ~1963) |
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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Posted: Thu Feb 18, 2010 9:43 am Post subject:
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I may have misunderstood part of your question.
For the supply voltage measurements on the IC's you should have +12 volts on pin 8 of U3, Pin 4 of U1 and pin 24 of U2.
You should have -12 volts on pin 4 of U3 and pin 11 of U1.
If those are OK, then continue to check the other voltages....
bruce _________________ www.sdiy.org/rfeng
"I want to make these sounds that go wooo-wooo-ah-woo-woo.”
(Herb Deutsch to Bob Moog ~1963) |
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Monstruarte
Joined: Sep 25, 2009 Posts: 73 Location: Argentina
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Posted: Thu Feb 18, 2010 6:07 pm Post subject:
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ok, I check everything you said.
The pin 8 of U3, Pin 4 of U1 and pin 24 of U2. have +12 v, this is perfect.
The pin 4 of U3 and pin 11 of U1. have-12v, this is also perfect.
Then the rest:
I pull it out the IC U3 and check your other ideas.
- The voltage at the center solder lug of R63 smoothly change when I adjust the knob, this is ok.
- The voltage on Pin 9 of the CD4067 change smoothly when I adjust the knob, this is ok.
- The voltage on pin 2 of the socket for U3. varies change nice and smoothly, according to the movement that I do on the knob, that's fine. the range is from 0V to 7.5V. this is when the step is stopped. When adjust the knob for the sequencers active step, the voltage changes according to the position of the knob for each step. this is perfect.
ALL IS PERFECT, WTF????????????
with regard to the advice you give me. -continue checking the signal in and out points of the IC's all the way to the output jacks-do not know exactly where to go, could you give me some hints?
bruce thank you very much |
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jordroid
Joined: Jan 17, 2010 Posts: 193 Location: ithaca, new york
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Posted: Thu Feb 18, 2010 6:27 pm Post subject:
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Checking out the schematic for this section, if you have correct voltages up to pin two of the TL082 U3 you are very close to having it at the CV output jacks.
Only the TL082 U3 and it's components, and the TL084 U1 are left, and the jacks themselves. I would very carefully check those IC's and all associated resistors and caps for correct values and good shiny solder joints, maybe just reflow any joints that look suspect .
One of the more common problems is a simple miswired jack, i have done it a few times, and it's worth triple checking them.
You are almost there! |
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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Posted: Thu Feb 18, 2010 8:47 pm Post subject:
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Good advice from jordroid. You are very close to getting this working
Put all the IC's in -
Check voltage at pin 1 of U3. Black lead of voltmeter on Ground, Red on the pin 1 of the IC...
This is the output of half of that Op=Amp. As before - the voltage should change nice and smooth as you rotate the Course tune pot.
Then check Pin 6 of U3 - this is the input for that part of the IC -
The voltage should change nice and smooth as you rotate the Course tune pot
Then check Pin 7 of U3 - this is the output for that part of the IC -
The voltage should change nice and smooth as you rotate the Course tune pot.
I really have a gut feeling this is where the problem is - but your measurements will verify if it's working or not.
If it's working to this point you've almost got it. If it's not correct here, it's either a bad IC, poor or incomplete soldering or an incorrect component.
I have missed soldering an IC pin more than once
If everything looks good, go on to the next IC - U1.
Look at the schematic and follow the same method we have used on U3. Measure what's goin in, compared to what's going out. Any drastic change and you have found roughly where the problem lies.
bruce _________________ www.sdiy.org/rfeng
"I want to make these sounds that go wooo-wooo-ah-woo-woo.”
(Herb Deutsch to Bob Moog ~1963) |
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