No distortion from Aion Refractor Build

[rmsmarr]

I'm getting no overdrive from Aion Refractor build.  All pots work as expected. Except when I turn up there is no distortion.  I've double checked all part values twice.  I'm using 2 D9 series Russion diodes with a fv .29.   C16  is oriented with the proper polarity as all electrolytic caps

IC voltage readings are as follows with 9.2 voltage input reading pin1 -8:

IC1

1. 4.6
2. 4.6
3. drifting 2.9 -4
4.. 0
5. 4.59
6. 4.6
7. 4.61
8.  8.2

IC2

1.  4.65
2.  4.6
3.  4.6
4. (-8.6)
5. 4.6
6. 4.59
7. 4.6
8.  16.8

IC3

1.  9.2
2. 4.68
3.  0
4.  4.35
5.  (-8.9)
6. 4.25
7. 4.5
8. 9.2

Running a tone thru the signal doesn't seem to break down anywhere.

And I get tone at IC1 one every pin except 4 and 8

On IC2 I get tones on pins 1,2 and 6,7

I'm including detailed pics of the underside and top of the board.
I appreciate any help as I totally stumped at this point.

[Slowpoke101]

Check this modification
https://aionelectronics.com/wp-content/uploads/2018/06/refractor_error_fix.pdf

[rmsmarr]

Thanks Slowpoke101 for the heads up.  I'll do that fix tomorrow and hopefully that will fix my distortion problem.

[rmsmarr]

I've applied the correction mod and still no noticeable gain.  At his point I have no tone with the signal tracer on IC2 pins 2 & 6.

l'm wondering about the dual gang pot.  Testing with the signal tracer on each gang on lugs 1 & 2

[rmsmarr]

I've applied the correction mod and still no noticeable gain.  At his point I have no tone with the signal tracer on IC2 pins 2 & 6.

l'm wondering about the dual gang pot.  Testing with the signal tracer on each gang on lugs 1 & 2  I should get signal on one with it increasing on 2 as I turn pot?  On the upper gang(edge of the board) I get tone on 1&2.  On the lower gang I only get tone on 1.

Would that be the pot failing with the gain stage?   Not really sure how to test the pot in circuit?

[Slowpoke101]

Don't worry too much about IC2 yet. IC1 and the gain pot are of the most interest at the moment.
Set the Gain to minimum and set both the Tone and Volume to mid-way.
Power up the effect and apply an signal to the input. Make sure that the effect is engaged and not in Bypass mode.
Use your audio probe and check IC1 pins 1 and 2. There should be a clean signal on both pins and at the same volume level. Now test pin 7. With Gain at minimum there should be no signal (or almost no signal) on pin 7. Turn the Gain pot up slowly while listening to pin 7. The volume level should begin to rise and get extremely loud when the Gain pot is at maximum.
Let us know what you find.

[rmsmarr]

Thanks for you help Ian

I ran a signal through the pedal with the Volume and tone set to midway Testing IC1 pins 1&2 have clear balanced signal and pin 7 responds when the gain is turned up clockwise. I wouldn't say it got extremely loud but equal in volume the input.

[Slowpoke101]

Ah, interesting result. Your gain stage is behaving as a variable attenuator.

What is most likely wrong is an incorrect component installed or a broken circuit trace. The IC1B gain stage will do exactly what you described if R10 (2K) is not connected to terminal 3 of the GAINA section of the dual gang potentiometer.
With the pedal un-powered, set your multimeter to low resistance test and check if that terminal and R10 are connected. If they're not connected just bridge the break with a piece of wire.

Make sure that R6, R10, R11, R12, C7 and C8 are the correct values.

[rmsmarr]

Ian

I checked R10 and it in fact a 2K resistor.  I did a continuity check from r10 to pin 3 on gain a and they are connected properly.  I also checked R6, R11, R12 and C7,   They are the correct values.  I believe I have the wrong value for C8  I don't have a 390pF MLCC can I use a ceramic disc cap?

Thanks for your time

[thermionix]

I don't have a 390pF MLCC can I use a ceramic disc cap?

I used ceramic discs in mine, no problem.

Actually, scratch that, I'm confusing this with a different build.  There are no ceramics in my Refractor, I used a film for the 390pF.  But I would have used a ceramic disc if I had one.  I'm sure it will work fine.

[rmsmarr]

You are a correct sir.  I used a 390 pF ceramic disk and it now works fine.   I don't how many times I looked at the 390nf film cap I had
on the board and thought it was correct. It finally occurred to me it was rather large duh!   

I appreciate everyone's help. Thank you so much.

[Slowpoke101]

You got it working  Good news. Always happy to help.
It's not hard to install the wrong component particularly as the writing on the component can be so very small. I have seen some high voltage film capacitors of that value (390pF) physically as large as the capacitor you used so I didn't think that it was out of place on your board.
Enjoy playing with your new effect 

[thermionix]

There is also a 390nF in the Refractor.