Suhr Riot Fixed build sounding terrible - Bad diodes?

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Suhr Riot Fixed build sounding terrible - Bad diodes?

negativefx
Issue: Strumming lightly has no output.  Strumming hard only produces high-mid heavy fuzz-like tone with no sustain and no discernible difference in volume.  The note sounds for a short time, then just cuts.

Volume control works, gain/tone/switch don't appear to have any effect on output.  Works fine in bypass.  I triple checked wiring, photo overlays of the layout both front and back.

I swapped the JRC4580D ICs as a hopeful quick fix but the problem persists.

Is this likely a problem with the diodes?  

I tested every diode and matched the relevant ones before placing on the board, but I guess those 1N34As or even an LED could have blown somehow.  There's no LED light-up from the board when on and playing.   I also tested every cap and stuck to +-1% tolerance for almost every one.

Any ideas?

I'll post IC voltages shortly.
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Re: Suhr Riot Fixed build sounding terrible - Bad diodes?

negativefx
IC1
1| 0  
2| 0
3| 4.78
4| 0
5| 0
6| 8.34
7| 9.16
8| 9.59

IC2
1| 1.32
2| 0.73
3| 0.75
4| 0
5| 0.65
6| 8.85
7| 8.85
8| 9.60
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Re: Suhr Riot Fixed build sounding terrible - Bad diodes?

JaviCAP
Administrator
Hi,

If you have 0v on IC1 pin5, you have a problem there and this rail is connected to ground. Check connections / solder bridges in this area.

BR
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Re: Suhr Riot Fixed build sounding terrible - Bad diodes?

IvIark
Administrator
Yes your problem is with IC1.  Close to 9V at pin 7 and 8 is also definitely wrong and I think you may have a micro bridge there as well.  

8 should be around 9V, 7 should be around half that, so check those links under the IC and at the top right are correct, knife the gaps between rows to make sure there are no unwanted solder bridges, and redo all the cuts to make sure there are no burrs in the holes causing problems.
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Re: Suhr Riot Fixed build sounding terrible - Bad diodes?

negativefx
You guys are awesome.  Found a burr in the cut between 4 and 5.

Pedal works great now but there is a lot of hiss and hum when it's on but guitar is muted. The hiss raises and lowers in volume with the gain knob. Is that expected from this pedal or is some biasing needed?  It's getting late but I'll check the voltages in the morning.

Thanks!!