Author Topic: More help with MOAR PCB Build - no signal  (Read 155 times)

Sky

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More help with MOAR PCB Build - no signal
« on: May 17, 2017, 01:36:25 PM »
I am somewhat embarrassed that this pedal is still not working, but I really want to get to the bottom of it so here I am again.  I don't have anyone to go to for electronics help outside of this forum so I might be posting a lot more for help in the future.  Thanks in advance to all the kind pedal building souls out there! 

I am getting no signal whatsoever. I have searched for solder bridges and scratched along the pcb to eliminate the thought of microscopic solder bridges.  I did have this pedal working at one point after desoldering D3 and flipping it around to match the picture on the  1590G pedal building Tutorial (the picture contradicts the polarity shown on the pcb): http://www.madbeanpedals.com/tutorials/downloads/1590G_BuildGuide.pdf

Though it worked during that test, the next time I went to try the pedal the signal had once again disappeared.   

Right before this, in preparation to put the PCB inside the enclosure, I realized I needed to bend a few capacitors to get them to fit inside the 1590G.  These capacitors were C10 and C7.  Because my voltage readings from my IC were so weird on the pins 5, 6, and 7 I though that maybe I had jacked something up with the C7 Capacitor when bending it downward (can it really be that sensitive?).  I have since replaced but not soldered it in completely just in case I jacked it up.  Upon this last check I have noticed that all my poking and prodding at the PCB has lifted the metal circle pad in the C7 location. (possibly over heated :-[ )  ...Does this mean the PCB is ruined?  It's not completely lifted off the PCB and on the other side of PCB the metal circle is there which makes me think contact can still be made. 

So.....putting aside any of my mentioned thoughts and fears, I am not sure if my issue really lies in any of the things mentioned above.  Whether it be the C7 or D3 or possibly a solder bridge or just something else completely.  Any suggestions or advice of any kind is welcome and appreciated. 

Thank you so much for helping me trouble shoot this problem. 

My current IC voltage readings:

1: 3.99v
2:  4.12v
3: 3.29v
4: 0.1mv (sometimes 0, but fluctuates to 0.1mv mostly)
5: 54mv  (this one fluctuates.  I got a reading of 11.93mv earlier in my testing before it started to hover around 54mv)

6: 2.98V
7: 2.007V
8: 9.25V

Moar Schematic and build info: http://www.madbeanpedals.com/projects/1590G/Moar.pdf

My Pictures:  (This is after I had taken out the C7 and reinserted a new one with out soldering it in.  For testing I purposely put it in on the wrong side of the PCB.  Some pictures show the C7 and others just show the circle pad that has lifted a bit)




somnif

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Re: More help with MOAR PCB Build - no signal
« Reply #1 on: May 17, 2017, 01:57:28 PM »
It looks like your pots aren't soldered in?

BrianS

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Re: More help with MOAR PCB Build - no signal
« Reply #2 on: May 17, 2017, 02:51:56 PM »
To ensure you're making contact on the lifted pad just solder the cap leg over to the pot leg or take a piece of a resistor wire and solder it between the two points.

Why are you putting C7 on the bottom of the board? It's not going to hurt anything to bend it over as long as the leads are not contacting anything. If you want to go the extra mile put some shrink wrap over them.

Your IC voltages might come up to where they should once you solder your pots in. 

Not sure what's up with D-1 to D-3.  The schematic shows 1 and 2 going the same direction and 3 being opposite.  Im no expert on reading these so I hope someone will explain it if I am wrong. 

PaulL

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Re: More help with MOAR PCB Build - no signal
« Reply #3 on: May 17, 2017, 03:05:05 PM »
It does look like one of your diodes is the wrong way round as already mentioned. Also I second the notion that all components need to be soldered on.  Also double check every component is of the correct value. Colour codes and markings first. Later if still having problems after taking the advice already mentioned remove the component and measure it with a multimeter. Also check that you haven't got any stray solder bridging two pads.

madbean

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Re: More help with MOAR PCB Build - no signal
« Reply #4 on: May 17, 2017, 04:59:58 PM »
That diode is shown installed backwards on the tutorial guide. Someone mentioned this a couple of weeks ago and I had forgotten that I corrected it afterward but never notated it in the doc. So, I've just now put a note in the tutorial pointing out the error. IOW, flip D3 around the right way!
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