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TOPIC: Troubleshooting 3.0

Troubleshooting 3.0 11 months 4 days ago #555

  • dubit
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Hi everyone.

I've been trying to troubleshoot my pedalshield for some time and I just realized I can't go any further with that alone.

So, that's the problem:
When I connect my guitar on the input, and then connect the output on my speaker box, there is a huge noise coming up, and no effects at all.
The first time when I power up the arduino the LED flashes a few times and then it keeps turned on continuously.

That's what I already done:

1> I checked the ground points and the 5V points (including that one on pin8 of the integrated circuit), everything is fine.
2> I checked all the pins from the shield to the arduino expecting that some pins were disconnected, that did'nt happen. Everything looks fine. And the capacitors are placed in the correct position. The led too.
3> Changing the effect doesn't seem to help, the same noise still pops up.
4> When I play any string on my guitar, it seems to send the signal to the box, once the noise changes the pattern in the exactly same time when I play the string and ends when I stop playing it, but it's still noisy, there is no tune or a guitar timber at all.
5> When I press the big button in the middle of the shield the noise stop while it's pressed. When I press the touch-buttons nothing seems to change.
6> Nothing changes when I turn the switch either.
7> There is no short-circuit between components after the assembly (as far as I can see)

Does anyone have any clue how to solve it?
If any other information could help you to help me, I'd be glad to share with you.
Last Edit: 11 months 4 days ago by dubit.
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Troubleshooting 3.0 11 months 3 days ago #556

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Hi,

I guess you already did this:
www.electrosmash.com/forum/pedalshield-u...alshield-uno?lang=en
What do you get when you do:
2. Check the output stage: You can load the sine-wave generator program. It only uses the output stage independently that the input is wrong. If it works you can be sure that the second op-amp area is good. If not check for resistors placement, IC is the correct one? orientation?
Are you able to generate a sinusoidal waveform?

You can send us some pics of your pedal, sometimes there is something obvious that another pair of eyes could spot (our mail in the "contact us" scrolling down the website)
and then connect the output on my speaker box,
Do you mean a speaker or a guitar amplifier?
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Troubleshooting 3.0 11 months 3 days ago #557

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Alright!

So, here is some update: Sine wave code looks nice and clean. I push the buttons and the tune changes as expected. Here is a video showing it: vid.me/y1R6

and those are pics:





i.imgur.com/GXQTGOU.jpg
/\ The forum seems not accept the img thing, so i just put the link here


Im sorry for the confusion, I only used my guitar box as you can see on the video.
As far as I can see i can't say that I saw any mistake on the assembly, I hope you can help me fix it

Thanks in advance
Last Edit: 11 months 3 days ago by dubit.
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Troubleshooting 3.0 11 months 3 days ago #558

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Just an update video trying tremolo:

vid.me/7WfV

All other effects have the same problem, this really huge noise with the effect on the background... It seems some filter might be working badly.
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Troubleshooting 3.0 11 months 1 day ago #559

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Thanks for the videos.
At the input of the circuit there is a potentiometer (white one) labelled VR1.
Did you try adjusting it?
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Troubleshooting 3.0 11 months 15 hours ago #560

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Yes, I did... It does change a little bit the noise, but still, it doesn't seem to fix it.
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Troubleshooting 3.0 11 months 14 hours ago #561

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The output stage is definitely working because you can generate sine waves without problems.
Its easier if you load the clean code because it should not add much noise or distortion to the signal.
The components and placement also look good... I would touch with the solder iron and a bit of solder all the joints to make sure that they are good and then with the multi-meter you could check the connections and resistors to see that all its all right.
Make sure that:
- You have 2.5V in both ends of R2.
- In the TL972 you have 5V on pin 8 and 0V in pin4
- In the TL972 without any input or output connected (just the pedalshield connected to the computer) you have around 2.5V in pins 5,6 and 7 (i read 2.1, 2.9, 2.9 in mine, just something around 2.5)
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Troubleshooting 3.0 11 months 11 hours ago #562

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I loaded the clean code. The noise is still there, no matter which effect I use, the noise is supper high... I can listen to the effect in the background, with a very low intensity though.

There is 2.5V in both R2 ends using the ground as reference.
there is also 5V on pin 8 and 0V on pin4. pin 5-6-7 have 2.6/2.9/2.9 V respectively.

When I push the switch one and the led turns off, i can use my guitar clearly like the pedal wasn't there (well I know that this is suppose to happen, but just another info), Any other ideas? It looks like a filter problem, I replaced the solder and the issue is still the same, also checked all pins and they are ok.
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Troubleshooting 3.0 10 months 4 weeks ago #563

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Alright,

So I tried to check the circuit point by point and the voltages that should be applied at each node.
And I found out something intriguing about it.



So, I hope I am wrong, but that's what I see during the testing

The capacitor number 6 is in the same node as the voltage divisor, when it should be connected between the 5V and the Ground seeing from the schematic point of view, I am just a bit confused cause in the layout design it seems to connect between 2.5V and the ground indeed.

I recorded a video to show it, I hope you find out that I am doing something wrong. But it might be the cause of the problem.
vid.me/T6BD
Last Edit: 10 months 4 weeks ago by dubit.
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Troubleshooting 3.0 10 months 4 weeks ago #564

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The capacitor number 6 is in the same node as the voltage divisor, when it should be connected between the 5V and the Ground seeing from the schematic point of view, I am just a bit confused cause in the layout design it seems to connect between 2.5V and the ground indeed.

You are totally right, I edited the schematic to make it easier to understand and I put the cap in the wrong rail, the original schematic looks like this:

ps1-divider.png


So C6 decouples 2.5V and C11 decouples 5V.
Dont worry what you see its fine.


Can you check your 3PDT switch? it should work like this:
www.electrosmash.com/forum/pedalshield-u...shooting?lang=en#535
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