beginner debugging

[milkchan]

I am having a hard time figuring out where to start. I am building an easy face pedal and it doesn't work. I'm trying to find out where the circuit is having problems and I don't understand the numbers I'm looking at. I have been testing voltage using a multimeter by placing the black probe on the grounded point and touching the red probe to other places on the circuit. I don't know how to follow a circuit so it all seems pretty random to me. Many of the components read close to 9 v, but some don't.

all pots 100k, 250k, 500k, all read 0.
the 33k resistor reads 8.90 on one side and 0 on the other
the .01 capacitor reads 8.93 on one side and 0 on the other
the 3.3 capacitor reads 8.93 on one side and 0 on the other
the 470k resistor reads .1 on one side and 8.95 on the other

I don't know what any of this means. I also have no idea how to measure resistance. I also don't understand how to know if all of the components are grounded.

Where to begin?

[niftydog]

I may be blind, but I don't see a 470k resistor anywhere for starters.

Ok, all those voltage... BAD. You have major problems which seem to numerous to be dealt with. I suggest you start over taking more care and reading up a bit more around the forums.

You are measuring the voltages 100% correctly.

Resistance is measured by simple placing the meter in resistance mode and placing the probes across whatever it is you wish to read the resistance of. Be warned that reading resistances whilst the component is in circuit is highly likely to lead to misleading results.

Disassemble your project and measure all the resistors. It's often easy to make mistakes when reading the colour bands.

Have a search around here (maybe in the FAQ?) for a method for testing transistors and check yours incase you've blown 'em up!  :wink: