[sdiy] problems going from breadbaord to pcb/solder

[Dan Snazelle]

a friend of mine has been working on a vclfo partially based on 
the ray wilson VCLFO.

it uses a triangle core with a lm13700, an integrator, and a tl072 comprator

it worked without ANY problem on the breadboard

however, when he soldered it up on perfboard the following problems arose:

1. the symetry is off. mainly as the oscillator gets slower and slower, the symmetry falls out of line. it is fine at higher speeds

2. at lower speeds, the oscillation dies. (at speeds which work on the breadboard)


I told him to try changing the hysteresis resistor value and cap on the comparator and this DID help somewhat (it kept the osc from dying)

however, things are still not quite right.

IS THIS due to the difference between the capacitance on a breadboard and the capacictance on a soldered board?

or could it be something else?

anyone have any ideas on how to save this?

i am very interested in the results as I will soon be moving some of my projects from breadboard
to finished pcbs


thanks so much



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