Finally got the foxrox octron working

[Lost_soul]

It's the circuit with the switch and C21.



It's pretty normal to go over a circuit and kick the tires a bit.   No matter how much time you spend on it, next week you will think of something else 


Clearly pins 6 and 7 are connecting, even from the voltages.  You can get weird results like that when there's a bad connection (somewhere).  If pin 5 is really different to pins 6 and 7 I'd start to be suspicious the opamp has a problem.

Well you ARE right!!! The opamp really was the problem. I changed it and bam the voltages now across pins 5,6,7 are the same 4.8v. Thank you rob. Now as I understand the voltages are all right. I wish I could figure out how to read voltages and know what they should be at any point in a schematic but idk where to start.
I will try your mod in the morning and report back as it's 3 am here.
Thank you again man.

[Rob Strand]

Well you ARE right!!! The opamp really was the problem. I changed it and bam the voltages now across pins 5,6,7 are the same 4.8v. Thank you rob. Now as I understand the voltages are all right. I wish I could figure out how to read voltages and know what they should be at any point in a schematic but idk where to start.
I will try your mod in the morning and report back as it's 3 am here.
Thank you again man.

Cool you are pretty much there now.

For a lot of circuits the input and outputs of the opamps should all sit at about Vref (Vcc/2 or whatever).  There are a few instances where the multimeter loads down the voltages and you get less than Vref but you can have an idea that's going to happen if you see a 470k or 1M resistor there.   Things like oscillators/LFO are different.

[duck_arse]

I'm confused. I'm not sure I'm looking at the right, or current, thing. here, see what I see, pins 6 and 7 shorted, and the diodes not connected as per circuit dia, and 100k resistors, perhaps instead of 10k resistors.

as I say, I'm confused now, and daylight savings ends in an hour, so it's only going to get worse.

[Lost_soul]

I'm confused. I'm not sure I'm looking at the right, or current, thing. here, see what I see, pins 6 and 7 shorted, and the diodes not connected as per circuit dia, and 100k resistors, perhaps instead of 10k resistors.

as I say, I'm confused now, and daylight savings ends in an hour, so it's only going to get worse.

I am not sure what you mean. Isn't pin 6 and 7 connected together in the schematic? And there is a diode from pin 7 to a point and then another diode from pin 8 to the same point?

[duck_arse]

and here is the schematic:

when I look on this schem, which is the only one I can see in thread, I don't see a match. am I looking in the right place?

[Lost_soul]

when I look on this schem, which is the only one I can see in thread, I don't see a match. am I looking in the right place?

yes it's the right scheme. but could you elaborate what is the match you don't see? is it in the pin 6/7 and diode section or is it with the veroboard layout or what

we are discussing IC4 section. maybe you looked at another IC?

[PRR]

when I look on this schem, which is the only one I can see in thread, I don't see a match. am I looking in the right place?

That image is all whitespace and dim details. Here's where I see 6 and 7 connected.

[duck_arse]

excellent. yes, confused, and yes, I was looking otherwhere. pardon, carry on.

[Lost_soul]

Cool you are pretty much there now.

For a lot of circuits the input and outputs of the opamps should all sit at about Vref (Vcc/2 or whatever).  There are a few instances where the multimeter loads down the voltages and you get less than Vref but you can have an idea that's going to happen if you see a 470k or 1M resistor there.   Things like oscillators/LFO are different.

Thanks rob.
I measured the voltages on my vero and here are they:





They are a little different from the breadboard. Especially when the bright switch is ON. (Btw i only have until IC4 on the breadboard)
What does this mean.

[Rob Strand]

They are a little different from the breadboard. Especially when the bright switch is ON. (Btw i only have until IC4 on the breadboard)
What does this mean.

My first thought was the bright switch bypasses the filter at pin 7 IC1.2 and you are seeing the effect of more noise injected into the U4 part of the circuit.

Worst case the circuit could be oscillating, cause by the removal of the IC1 filter.

You could try putting a small valued cap across R31, say 470pF to see if it helps.

Scrounging for other causes:  there could be another small bug somewhere in the circuit or a soldering bridge.  Something related to the bright switch.  It wouldn't hurt to check the DC voltage on IC1.1 pin 1 and IC1.2 pin 7 with both bright and non-bright settings.   Then check C13 for any shorts or solder bridges.   

[Lost_soul]

They are a little different from the breadboard. Especially when the bright switch is ON. (Btw i only have until IC4 on the breadboard)
What does this mean.

My first thought was the bright switch bypasses the filter at pin 7 IC1.2 and you are seeing the effect of more noise injected into the U4 part of the circuit.

Worst case the circuit could be oscillating, cause by the removal of the IC1 filter.

You could try putting a small valued cap across R31, say 470pF to see if it helps.

Scrounging for other causes:  there could be another small bug somewhere in the circuit or a soldering bridge.  Something related to the bright switch.  It wouldn't hurt to check the DC voltage on IC1.1 pin 1 and IC1.2 pin 7 with both bright and non-bright settings.   Then check C13 for any shorts or solder bridges.   

Okay i will do as you said in the morning (again ahahaha).
What bugs me is on the breadboard the voltages don't change if the switch is on or off (except for pin 14 which become 4.6 instead of 4.8
But on the vero it's way off.

Maybe i have something wrong in the layout itself? But i checked the layout i made and it was fine. Has to be something wrong with the board itself.

I will report back the voltages of IC1.1 and IC1.7 and check for that c13.

Sorry for the trouble rob. You are a great guy helping people around with thier hobbies.

[Rob Strand]

Maybe i have something wrong in the layout itself? But i checked the layout i made and it was fine. Has to be something wrong with the board itself.

I will report back the voltages of IC1.1 and IC1.7 and check for that c13.

Sorry for the trouble rob. You are a great guy helping people around with thier hobbies

No problem, that's how things go.

It could be a layout problem, or a wiring problem.   It's not hard for small errors to creep in.   It's also hard to check your own work.  Just check everything and you might find something.

What bugs me is on the breadboard the voltages don't change if the switch is on or off (except for pin 14 which become 4.6 instead of 4.8
But on the vero it's way off.

It could be very well be a simple thing throwing it off.   What about if the bright switch wiring has a swapped pin.

[duck_arse]

me again. what's that thing circled, looks like a diode where there shouldn't be a diode?

[Lost_soul]

me again. what's that thing circled, looks like a diode where there shouldn't be a diode?

that is D0 on the layout which is d6 and 7 on the schematic. i just placed it to the right sharing a whole with R31.

[Lost_soul]

No problem, that's how things go.

It could be a layout problem, or a wiring problem.  It's not hard for small errors to creep in.  It's also hard to check your own work.  Just check everything and you might find something.

It could be very well be a simple thing throwing it off.  What about if the bright switch wiring has a swapped pin.

I checked the layout multiple times and there seems to be nothing wrong. I also looked at the switch and all connections are good. No swapped pins.

Idk, i will look further more to the board and compare it to the layout. I hate veroboard dude but at the same time there are no places here who make PCBs. Also etching one is kinda a pain in the ass hahaha.

Here are the voltages for ic1.

[Rob Strand]

I checked the layout multiple times and there seems to be nothing wrong. I also looked at the switch and all connections are good. No swapped pins.

Idk, i will look further more to the board and compare it to the layout. I hate veroboard dude but at the same time there are no places here who make PCBs. Also etching one is kinda a pain in the ass hahaha.

Here are the voltages for ic1.

It's possible there's nothing wrong and the problem is elsewhere but it pays to check.

You could try putting a small valued cap across R31, say 470pF to see if it helps.

I'd perhaps try that line of thinking.   Even if you add 10nF or 100nF across R31 then check the DC values.   While large cap values aren't a solution it shows the kind of problem we are dealing with.   From that point you can see if you can find a smaller value (like 470pF) which doesn't affect the tone but fixes the problem.   If you need a still need a large cap to fix the problem it might mean there's some sort of signal coupling on the PCB or in the wiring, then you would need to fix that first.

[Lost_soul]

Well, i just gave up on this circuit. I put a 470pf on the breadboard (which is supposed to have perfect voltages) as you said and the noise is still there. Maybe it's just the nature of the circuit. I will build another one later on the veroboard and box it. Or try to debug the one i built already idk.
Thank you rob for the great help but i am just done with this stupid circuit.

[antonis]

My dear Doctor..

Don't get me wrong but you've dived in troubled waters witout oil to pour on..

I mean, for toubleshooting a, more or less, complicated circuit you have to understand its individual building blocks as well as its overal function..

[Lost_soul]

My dear Doctor..

Don't get me wrong but you've dived in troubled waters witout oil to pour on..

I mean, for toubleshooting a, more or less, complicated circuit you have to understand its individual building blocks as well as its overal function..

I want to understand circuits and how they work antonis but idk where to start. And the problem is i don't have the head space to acknowledge both medicine and electronics but i would love to.

Should i start with the basics like how resistors, capacitors etc work and what do they do. How voltages work. Do you have a source?

[antonis]

i don't have the head space to acknowledge both medicine and electronics but i would love to.

You're venerated Sir, believe me..

Do you have a source?

Elementary high-school Physics (like Ohm's and KIrchhoff's Law's should be a good start..

Then go to Semiconductors but at your own risk..!!