I have been working on a circuit for a few months now. it allows you to sustain notes as you are playing through dividers.
http://www.flickr.com/photos/13918667@N02/2992198788/
THE 4046 is the only thing i need help with. the circuit used to work fine on breadboard and now that i soldered it permanently, it exhibits mass amounts of droop.
a guitar signal is fed through an input circuit (a preamp of some kind) which then goes into the input of the 40106. (this is not shown)
An ADSR (not shown)which is triggered by the guitar turns the 4016 on and off (high and low) which cuts the loop between pin 13 and pin 9 of 4046. when it is cut, this causes the voltage to be held by the CAP coming off of pin 9 (which is fed either by a 2m pot or a resistor)
NORMALLY (on the breadboard) this worked great. it would hold for quite awhile before droop set in.
BUT when i built it on etched circuit board, (at 15 volts instead of 12 but i dont know if that matters) the droop comes on SUPER fast. too fast to be usable.
so...i tried other caps but still no luck.
NOW I am wondering what is going on.
could it be the Long wires going from the pcb to the switch (the switch on pin 9 between resistor or 2m pot) it has to travel to the panel and then back to the pcb. (about 15 inches)
or could it be too close to some other wires?
why would it work so well on breadboard and then fail on a pcb? i would think it would be the opposite.
any help appreciated!
thanks
Did you clean the PCB of rosin/flux after soldering?
no
will this help and if so...can you explain How and with what chemicals????
i have never expereinced problems before with not cleaning the flux off so i guess i got lazy.
i have tried rubbing alcohol before without very good results and i was also afarid it would eat through the boards that have soldermask...is it a danger?
thanks so much
Isopropyl and ethyl alcohols generally don't damage solder masks. There are commercial solvent mixes to remove flux, but alcohol works about as well.