Queen of Bone 2 Troubleshooting

[natron_mn]

I finished assembling my Rullywow Queen of Bone 2 circuit (King of Tone clone). I get signal when the effect is bypassed, and both LEDs turn on when the footswitches are engaged, but I get the faintest sound when the footswitches are engaged.

I have no idea where to begin troubleshooting. I checked to make sure the cables weren't shorting out on any components, checked the orientation of my electrolytic caps, did a visual check to make sure I had no solder bridges, but I didn't find any issues.

I was so excited because I pleased with my soldering, thought everything was clean, but alas the effect didn't work. Any insights from these pictures, or any tips as to where to begin troubleshooting?

[PRR]

> tips as to where to begin troubleshooting?

http://www.diystompboxes.com/wiki/index.php?title=Debugging

[antonis]

Also, a reverse placed diode, according to PCB parts population...
(1Nsomething at the right end of diodes row..) 

[M.A.P]

Also, a reverse placed diode, according to PCB parts population...
(1Nsomething at the right end of diodes row..) 

antonis is right. D14 is reversed. ICs, caps and the other diodes are facing the right direction.

[natron_mn]

Son of a -- can't believe I missed that one! Thanks for catching that.

Is that diode in the signal chain of both footswitches? That is, would that reversed diode cause this minimal volume issue for both footswitches? Or am I missing the point of a dual overdrive?

[duck_arse]

in this image:



the pad for the 6th green wire along the bottom seems to have "lifted". you will need to confirm w/ your meter that the wire is connecting to the copper pattern, and the components, board-top and -bottom.

and we want those voltages from the debug page.

[natron_mn]

Thanks - I'll be able to look at my voltages tomorrow. As far as the pad, I think it's just that there is some gunk over it, masking the pad itself. I had to resolder that pad and it was taking a while with the desolder braid to get everything out of there. If it turns out the pad did come off, how would I replace it? Or would I have to get a new board entirely?

In the meantime, I've resoldered D14.

[duck_arse]

you only need to replace the connection to/from the pad, if it came off. trace what was connecting to that pad, and then make a wire link, either to that component, or scrape some of the black off, and solder a wire to the clean copper trace. and if it is connecting top to bottom, thru the hole, you need to make that connection too.

[Keeb]

Son of a -- can't believe I missed that one! Thanks for catching that.

Is that diode in the signal chain of both footswitches? That is, would that reversed diode cause this minimal volume issue for both footswitches? Or am I missing the point of a dual overdrive?

That diode is part of the charge pump that supplies both dual opamps with 18V. Those 18V are divided to create the VB at 9V which is used to bias the opamp inputs. So yes, if the charge pump isn't working both channels would be affected.

I don't know if that's the entire explanation but it would affect the entire circuit.

[natron_mn]

You guys were right - it was the diode that caused the issue. I resoldered it correctly this morning, got a chance to test it just now, and it sounds fantastic!

I think I'll still measure the voltages later in the spirit of learning. But for now I'm really happy it works. Before this pedal, I've just built a boost before. So I'm glad I was able to assemble a slightly more complex circuit.

Couldn't have done it without your extra sets of eyes - thanks!

Keeb - thank you for the add'l explanation. That makes sense.

[natron_mn]

Update - I'm now getting a high pitched, slightly dull squeel from the left channel. It gets worse when the gain on that channel is turned up.

I thought maybe it was the amp (tube), so I plugged it into another one (solid state). Not as loud on the solid state, but still noticeable. The right channel produces a little unwanted noise, but certainly tolerable.

Any idea what would cause the squeel? My Fuzz Factory was even quieter than this pedal!

[natron_mn]

Was told by Ben at Rullywow that this is common if the charge pump IC is not above the audio range, and could be caused by fake ICs from ebay or Tayda.

I did in fact buy it from Tayda, and am going to look for a new IC to see if that fixes it.