Aion Halo Big Muff Clone - Power Delivery issues

[jung_]

I'm having strange issues with power delivery and can't figure out the problem.

I'm using this kit - https://aionelectronics.com/project/halo-ehx-big-muff-pi-kit/ - substituting parts with the values for the Green Russian from the documentation provided here - https://aionelectronics.com/project/halo-ehx-big-muff-fuzz-pcb/ .

Since the kit comes with the midrange mod, which I don't want, I've installed the switch but replaced CX2 with a 10 nF cap and jumpered the ends of CX1 to the ends of C10.

Using a DC power supply at 9.45V, the circuit bypass works when the footswitch is off, and the LED lights up when the footswitch is on. Using a battery, the LED does not light up. When the footswitch is on, no signal passes.

Anywhere I probe in the circuit, the voltage is lower than the ground. I can't find the problem.

The transistor voltages are:

Q1
C = -220 mV
B = -0.37 mV
E = 0.00 V

Q2
C = -220 mV
B = -0.37 mV
E = 0.00 V

Q3
C = -202 mV
B = -0.35 mV
E = 0.00 V

Q4
C= -223 mV
B = -0.29 mV
E = 0.00 V

I've taken images of the assembly in the enclosure, and each PCB outside the enclosure.
















I'm honestly stuck here. Is there any mistake the more experienced here could point out?

[soggybag]

Sounds like the trouble might be at the dc jack. You could have mixed up the battery and power connections. Double check this.

Check voltage with the multi meter starting at the dc input to the circuit with the effect on. Look at the schematic and check that you have 9v everywhere you expect.

Make an audio probe and start probing from the input Jack. Follow the signal through the circuit until there is a problem.

[DIY Bass]

If you are getting no response at all using a battery, do you have a plug inserted into the input?  It is so easy to forget that most pedals are wired so that the input plug connects and disconnects the battery.

[jung_]

Ok. It seems that the DC jack is some but not all of the problem. With the battery connected, the transistors show numbers in line with what is in the project documentation, but the circuit still passes no signal with the effect on and the LED still does not light up. I'm going to try the audio probe later.

[radio]

https://www.google.com/search?q=big+muff+voltages&tbm=isch&source=univ&client=firefox-b&sa=X&ved=2ahUKEwi9prTul6fjAhUKYlAKHWa4ARQQsAR6BAgCEAE&biw=1280&bih=859#imgrc=lCSE9tB7CbDIGM:

Here voltages are shown in a big muff circuit.

Its only the Creamy dreamer who s emitters are directly connected to ground and are exactly 0v

But your other values are fare more off .

[soggybag]

You have to make yourself an audio probe. This is by far the best debugging tool for pedal builders. I have solved so many problems with this it's embarrassing.   

Tl;dr solder a cap, any size, 100n is a good choice to the tip of a 1/4" jack. Connect your guitar or a sound source to the pedal. Connect your amp to the audio probe jack. Touch the other lead of the cap, remember it's connected to the tip of the jack going to your amp, to points in your circuit. If you hear audio this area is working.

You Can make this fancy by adding wires, you'll need to ground the audio probe to your pedal with an alligator clip.

If there's something wrong I get out the audio probe and start at the input. It's a sanity check, if I'm getting audio from tip of input to the tip of the output I know the probe isworking and I haven't accidentally grounded the input.  that's never happened to me...

Then move to the far side of the input cap. You should hear something here, if not you probably have problems with the switch, you can probe that! 

Next on to the emitter or collector of the first transistor or output of the first op-amp stage. The signal should get louder here. If not check the voltages here with the meter.

Keep going until things are not what you expect, the sound is gone or a lot quieter than you expect.

Follow the schematic and the PCB layout. Not only is this the best debugging tool for pedal builders it's an awesome learning tool  . Ever wonder what's happening at that first clipping stage? well now you can hear it! Thought about building a muff without the tone section? You can hear yours as a preview.

I can't stress how useful this is for the cost of a single 1/4" jack and one capacitor!

Search the forum there are copious discussions of the audio probe.