[SOLVED] FACE Melter trouble... Please HELP :(

A

Arasek

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Hi guys, I am lost... This is not my first build, i have build 3 tube screamers and everyone work just fine. But this face melter is melting my brain right now.. I really dont know what to do now. Please help me find a solution.. Or at least post your PCB wich are working..

When i turn pedal on, i hear Loud 50HZ. Pots doesn't work. Even switch doesn't do anything. When turned off i can hear guitar playing.

There are few links to photos of PCB..
and documentation
Thank you !

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Ales
 
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temol said:
Maybe you should reverse OUT jack wires? Looks like OUT jack tip is connected to pcb GND instead of the 3pdt daughterboard.
Click to expand...
Hi thanks for your advice. I have replaced wires and finaly i can hear something... Now after turn on i can hear really weak distorted guitar signal. But the pots doesnt work.. What now? Any ideas how to find an issue ?
 
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What do you mean by "turn on"? Power on or engaging 3pdt switch? Do you have clean guitar signal when bypased?
How about volume pot (labeled LOAD)? Any difference between min and max position?
What's the voltage on the pins 1, 2, 3, 8 of the IC?
 
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temol said:
What do you mean by "turn on"? Power on or engaging 3pdt switch? Do you have clean guitar signal when bypased?
How about volume pot (labeled LOAD)? Any difference between min and max position?
What's the voltage on the pins 1, 2, 3, 8 of the IC?
Click to expand...
Sorry for not being clear. I am not native speaker so excuse my language. I have clean guitar signal when bypassed. When i trigger footswitch[3pdt] and rise volume [load] to max, I hear really but really weak distorted sound. Other POTS doesnt work. The MOIST and GUSH Switch do the job (at least i think since the output signal is so weak.)

1-4,53V
2-4,56V
3-4,34V
4-8,80V
5-0,26V
6-4,55V
7-4,55V
8-4,54V

I also tried to measure diodes and found that diode no.80 (the black one - 1N5817) Has 0,26V on cathode and 0 on Anode. Could this be an issue?
 
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If you are using the PCB IO board you should not be soldering anything at all to any of the LUGS on the 3PDT, only the IN OUT SW GND and the far left and far right of that PCB io board go to your in and out jacks. Wire it EXACTLY like this - don't solder any wires to the 3DPT lugs as you have done. And do not socket the PCB IO like you've done, those are permanent connections and should be all direct wired.

1628633798818.png
 
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Arasek said:
1-4,53V
2-4,56V
3-4,34V
4-8,80V
5-0,26V
6-4,55V
7-4,55V
8-4,54V
Click to expand...
Are sou sure about this? Pin 4 it's a GND and should read 0V, pin 8 should read around 9V (minus voltage drop on a 1N5817 diode).
Also - make sure you did not swap places 5k and 500k potentiometers (Dirty, Booty).
Here's a signal path. Make an audio probe (I won't describe how, it's been discussed here many times, use search function) and check the signal level at points marked blue. You should have clean guitar, without boost, up to pin 3 of the IC, then signal distorted and boosted starting from pin 1.

1628658020739.png

ps. for the testing you do not need a 3pdt switch. You can wire IN/OUT jacks directly to the board.
 
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While I'm certainly a fan of socketing the foot switch board, I'd recommend a JST or similar type connector for this purpose. The mill-max style pin sockets are not great for wire to board connections...

My primary suggestion here is to clean all the wire to board connections. Solid core 24AWG copper wire might be a good choice for you; it doesn't fray and it's easy to route. Use solder wick & a desoldering pump, try to be quick with it...don't linger too long or you'll lift a pad.

Right now, without wanting to be unkind, it's a bit unruly. A random strand could be creating a short somewhere and it would be difficult to figure out where to start looking.

Best of luck here.
 
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Hey, thank you all for your suggestions. I will look at it at the weekend. Currently i am busy (work, etc...). I ll let you know where the mistakes were made. :) <3
 
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UPDATE: Hi guys, i have removed pots, wires and 3pdt board.

I tried to make sure there is not any shorts or weak spots. Also clean the board with Alcohol .
But... There are few things that are wrong, at least i think.
1) I have measured IC pins and there is still 8,4 V on PIN 4. There should be a 0V since it goes to ground.
2) Also there is 4,5 V on PIN 8. There should be 9V - Voltage drop on Diode 1N5817.
3) Voltage measured on DIODE 1n5817 is 0,26V.

What i should do now ?

For now i am not going to even try to put on pots, jacks etc... Because i dont want to destroy PCB..
There is the Solder-side of my board.

THANK YOU GUYS!!! :)

[NOTE: I have measured voltage on pins with IC on it... This is just photo without IC. ]

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First make sure you are numbering the pins correctly. This is different chip, but all dual op amp ICs have the same pinouts. Your voltages could be pretty correct if you are numbering the pins incorrectly.

1628901677332.png
 
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Okay, i am idiot. The correct values are..
1 - 4,54V
2 - 4,56V
3 - 4,53V
4 - 8,56V
5 - 4,50V
6 - 4,59V
7 - 4,57V
8 - 0,26

Gotta check continuity of all spots via schematic. I'll keep you informed. :)
 
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temol said:
Still wrong... pin 4 should read 0V, pin 8 - 8.56V.
Click to expand...
I feel so embarrassed.. Please i need explanation.. When i measured the pins for the first time, i placed "+" (red probe) to "+" on pcb board, then i placed (COM black probe) to pin no. 4. IT showed me 8,5V.

THEN i tried second method.. I placed black probe on ground and red probe to pin no. 4. Now i can read the 0 V. This method also show right voltage on pin no. 8 - 8,6V .
How is that even possible.. I am sooo confused. Thanks in advance..
 
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Take deep breath.. relax.. take a look at the schematic. You have to be very meticulous when it comes to troubleshooting.
The red line on a pcb layout connects OUT and middle leg of the DIRTY potentiometer. Are you sure? Maybe middle leg of the LOAD potentiometer?
I do not hear any problems with hum.. it's normal for the drive pedal to hum a bit with controls maxed, expecially bare board, without the enclosure.
Box it and we'll see..
ps. What pickups is your guitar equipped with? Single coils, humbuckers?
 
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