I can't seem to get Joe Davison's METRONOME (http://analogalchemy.com/pedals/metronome.gif) to work, i have all good soldering joints, i had to wire up two 47k resistors in series to equal as close to 100 as i could... and i measured it and got about 97... the transistors i am using are 2n3904/2n3906 for the npn and a few different ones i got in a variety pack of pnp transistors...
it doesn't work...
what a simple circuit, and i can't get it working... how lame
well, it turns out that a few of the transistors that were in the npn pack... are pnp...
after a while of sorting them out, i sort of got it to work... for a while i got a cool constant noise... which changed pitch when i turned the pot... then i realized i missed one connection...
after i got that sorted out, it metronomed!! it didn't function properly with the pot... then i realized i used a 0.22uf cap instead of a 22uf cap. i changed out the cap to a 22uf one... and now it does NOTHING!
i even started it over... i said screw it, lets put it on a new board, real transistor sockets instead of the single pin ones... got it looking quite nice... but NOTHING again.
anyone mind taking a loot at the schem and see if they see any "Here-comes-a-mistake-most-n00bs-are-going-to-make"
even someone posting, "tough, fix it" would help
i know i can do this :(
Wooo Hooo... i fixed it! heh
so happy over something so small.
Congratulations! 8)
What was the problem? Don't feel bad.... we all make wiring mistakes and grab the wrong component from time to time. People who make no mistakes also build nothing. ;)
Take care,
-Peter
Oh come one Peter! I haven't made a mistake like that in at least 3 months. Oh yeah, I haven't built a pedal in 3 months. :) Never mind...
after messing around looking for transistor pinouts, and testing the transistors with my DMM to MAKE SURE they were pnp and npn (cause the multi-pack i got wasn't what they were supposed to be). I got them setup correctly.
Then i realized on the second board i made, i didn't connect the base of the second transistor to anything... that didn't help.
Then i realized the 1st and 2nd lugs on the pot should be connected... (guess my second monitor (the one i had the schem on) needs to be cleaned... didn't see the dot.
after all that it would only work if i was holding the pot... so then i made a ground connection from the back of the pot to the ground.
works well now =D
What i like to do when i am having a problem and looking at the schem doesn't help... i do it backwards. I look at my board and draw a schem from that... then i compare and see where i made a mistake.
Also, when i start something i always redraw the schem by hand so i can get a feel for where things go.
thanks
-sic
I don't have very many perf board circuits without clipped-out wires, components that aren't being used, or some other maming to an otherwise beautiful circuit...however, I did get the acoustic guitar preamp that I made for my brother to work the first time. That was an anomaly. I had to go to the doctor to make sure I hadn't contracted some strange illness :wink: ...just kidding