Problem with the ADSR

gabbagabi · Last edited by gabbagabi on Mon Apr 14, 2014 3:02 am; edited 1 time in total

Ahoi,

I've been finished the ADSR.
I put a Pulse Signal on the Gate In - nothing on the Output.

Turning the Pots, makes no change.
But the 555 is heating.

Maybe somebody got a similar problem before, or an idea what i do wrong?

yusynth · Joined: Nov 24, 2005 Posts: 1314 Location: France

If the 555 is hot this is not normal, this suggests that either there is an error somewhere in the value of a component or there is a solder bridge somewhere. A good thing to would be to measure voltages at some key points. For example what voltages do you get at the collector of the trannies with and without GATE signal (which is supposed to be at least 5V). What voltage do get at the pins of the 555 ?

gabbagabi · Posted: Mon Dec 01, 2008 3:15 pm Post subject:

1. thank you! the ADSR is the first module of your Modules that dont work immediately.

this Time I use the YuSynth LFO for the Gate signal

With signal on gate in
Q1 0v ; 0,7v pulse
Q2 0v ; 0,9v pulse
Q3 static 0,9v
Q4 15V
Without
Q1 0,7vstatic
Q2 0v static
Q3 0,9vstatic
Q4 15Vstatic

555
1 0v
2 0,9v
3 0v
4 0,9v
5 0v
6 0,1v
7 15v
8 15v

yusynth · Joined: Nov 24, 2005 Posts: 1314 Location: France

gabbagabi · Posted: Wed Dec 03, 2008 5:08 am Post subject:

I measure the Q Voltages at the Collector.

Cant find some Difference between my Parts on the board and the List-Pic

thank you very much 4 your help.
gabbagabi

yusynth · Joined: Nov 24, 2005 Posts: 1314 Location: France

gabbagabi · Posted: Wed Dec 03, 2008 6:26 am Post subject:

ups sry

it means i make 2 new ADSR

yusynth · Joined: Nov 24, 2005 Posts: 1314 Location: France

Thanks for the explanation Wink

gabbagabi · Posted: Wed Dec 03, 2008 10:27 am Post subject:

edit: i was wrong

gabbagabi · Posted: Wed Dec 03, 2008 11:33 am Post subject:

edit: i was wrong

yusynth · Joined: Nov 24, 2005 Posts: 1314 Location: France

You mean it auto-oscillates ?

If so can you post detailed photo of your PCB (component side and track side)

gabbagabi · Posted: Wed Dec 03, 2008 12:06 pm Post subject:

yes it oscilates

if move the caps on the copper side

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gabbagabi · Posted: Wed Dec 03, 2008 12:10 pm Post subject:

it auto osc. from the first moment - so i chang the caps
before i try it whith ceramic caps

gabbagabi · Posted: Wed Dec 03, 2008 1:32 pm Post subject:

i disconnect all caps
still oscilating

i disconnect the elkos at the Power input
now its oscilating with a high frq

try to connect and disconnect the other caps
it restarts to reheating the 555

and it stops to work

yusynth · Joined: Nov 24, 2005 Posts: 1314 Location: France

yusynth · Joined: Nov 24, 2005 Posts: 1314 Location: France

How do you power up the circuit ? Are you using a linear power suplly ?

gabbagabi · Posted: Thu Dec 04, 2008 1:31 am Post subject:

a linear
i forgot the loop, so i will focus also on a loop.

gabbagabi · Posted: Thu Dec 04, 2008 11:22 am Post subject:

the negative supply voltage was connectet to the wrong place

thank you very much for your support

Ali M · Joined: Sep 01, 2009 Posts: 96 Location: uk

yusynth · Joined: Nov 24, 2005 Posts: 1314 Location: France

Hi Ali

Which version of the ADSR have you built ?
Can you simply check with a voltmeter what voltage you get on the basis of Q1 with and without pushing the button ?
It should be 0V without and something like 0.7V to 1.0V when pushing.

Ali M · Joined: Sep 01, 2009 Posts: 96 Location: uk

Yves, i am getting some really weird errors with my circuit now. I found what may have been a short and since then the whole circuit is acting very strangly. I am getting 12v on the Vcc of my Op-amp and no voltage to any of the transistors.
I tried the other adsr I had built and that doesn't work either, the LED is premenantly on Confused

But I will focus on the first one, I was just hoping it would work straight away so I could compare voltages and swap ic's etc...

I have built the old version, and I etched my own boards. Maybe not the best idea, but there are no shorts and the continuity is good. Most circuits I build work, its rare that 2 of the same thing don't work.
I suspected the IC's, until the circuit was giving stange voltages now I feel it could be any number of things.

I am going to replace some components and give try and get it out of its sorry state today. I will report back asap.

yusynth · Joined: Nov 24, 2005 Posts: 1314 Location: France

Can you post some photos of your PCB : component side view and track view.

Ali M · Joined: Sep 01, 2009 Posts: 96 Location: uk

I tried taking pictures of the circuit but they really don't come out very well....
I swapped the 10 ohm resistors. Now I am getting an output.
The LED is lighting in responce to the settings of the front panel pots.
But the image on the scope seems to be either HIGH, gate on or LOW gate off. It doesn't seem to react to the front panel settings.

Q1
C = 0.7
B = 0
E = 0

Q2
C = 0
B = 0.7
E = 0

Q3
C = 11.2
B = 0.5
E = 0

When I push the trigger the voltages all go to '0' apart from Q3 collector, which stays at 11.2.

I think I am getting there. Will try to upload some pics with a better camera.

Ali M · Joined: Sep 01, 2009 Posts: 96 Location: uk

Sorted now,

I few of the resistors were not working. Now I am getting a nice smooth envelopes on the scope. I haven't got a CV midi convertor yet, to test the input.
And I am still a little concerned that I am not getting correct voltages to Q1 - Q3. But I have something going now and should be able to find my own way with it.

The other circuit that had the LED permenantly ON was a dodgy transistor, but I haven't got that one working yet, but It shouldn't be too tough.
Have learnt a great deal by doing this circuit. And I have never had so many components fail on the same board before, it must have been a short!

Thanks Yves, now I have to sort out that VCO!