Rump Roast build problem

[pjohns0]

Hello.  I'm trying to build a Rump Roast with the hybrid wiring scheme (boost / overdrive on a switch) and am having some issues.  When I power up the circuit, the LED lights up, but very dim.  There is a crazy amount of hum will little to no guitar volume passed.  If I ground the tip of one of the jacks, the LED glows at normal brightness.
Additionally, the bias knobs are turned all the way down and still read around 10 volts.

I suspect a wrong / bad component on the PCB, but I don't even know where to start.

Any thoughts?

[mgwhit]

Everyone suspects bad components, but it so rarely is.    Please read the Rules For Getting Tech Help and follow the suggestions in that post for helping us diagnose your problem.

You've got problems in two fairly separate portions of the circuit: the audio circuit and the LED indicator.  That suggests (at minimum) a wiring problem, probably related to improper grounding.  I'm guessing you've either miswired the footswitch or the jacks.  Read up, post pics and get out your DMM.  Good luck!

[jcuempire]

If I may add a relative noob opinion, look at your wiring 5 times against the diagram, walk away for a few hours and come back and look at it again.  It's amazing how you can stare right at a mistake and completely miss it.  Be systematic about it and you will figure out where you went wrong.  Also check all your solder joints with a magnifying glass.  I have weak joints and solder bridges all the time.  Good Luck

[Jamiroking]

Just from my experience with my own problems, when the signal cuts out or the led is dim sometimes, it usually means there's something wrong with the grounding. It could be something before your LED (e.g. a solder bridge that is shorting your signal/power to ground too early. Or it could be something in the main ground wiring running from the switch to the jack. My most recent pedal had something like this. The LED would flicker and be dim but I didn't notice much of a change in the signal (though it was rehearsal and I had earplugs in). It turned out to be a broken solder connection from the main ground wire from the stomp lugs to the jack, therefore NO GROUND!

This grounding issue is usually always the case for any issues I have