R.G.'s Test Oscillator problem

[Jamforthelamb]

Hey Everyone,
I built the Quick and Dirty Audio Test Oscillator from this layout.
http://aronnelson.com/gallery/TheBigMan-Layouts/osci1
All the transistors are orientated the proper way (I googled the pin out).
I substituted the 27k res. for 33k, the 9k1 res. for 10k, and the 910 for 1k.
I'm calling Q1 the left one on the layout, and Q2 the right.
Q1:
C=1.03
B=0.04
E=0.04

Q2:
C=8.32
B=1.03
E=0.47

I get a very quiet "click" when I connect the output cap to my computer speakers, but no oscillation.  I've checked, and double checked my soldering and can't find any errors.

Thanks,
JFTL

[Jamforthelamb]

I just noticed that in the original schematic seen here:
http://geofex.com/FX_images/q+dosc.gif
That the 2 of the capacitors are 0.01 rather then .1 (which is what I used in the layout).
Anyone think this might be my problem ?

JFTL

[bioroids]

It apears to be a mistake on the layout, the two 0.1uf capacitors on the left (next to the 4k7 resistor) are in fact 0.01uf on RG schematic.

I dont know if that can cause your problem, but at least it should move the oscillator frequency away from the expected 1Khz. I would try the correct value before any other thing.

I think also, the little white squares mean you need to break the track there (i bever used this method of construction, I could be wrong).

Luck

Miguel

EDIT: I wrote before you posted again. I think that can be a problem in fact.

[Jamforthelamb]

Ok, cool. I will try de-soldering the caps and switching them.

Yeah, I found out about the trace cutting the hard way  .

JFTL

[TheBigMan]

 

I've made so many %^&*ups with that circuit.  The layout does work, but I must have mistyped when I did the parts lists.  Yet another apology.  I'll correct it now.

[Jamforthelamb]

No worries man!
Changed the caps over and it works like a charm!
w00t!

JFTL

[bioroids]

Really cool then I'm glad it works!

Miguel

[RLBJR65]

Thanks all! I forgot all about that layout, I've been building some test equip. lately and that was on the list.
Thanks Andrew! Now I won't have to do my own layout.

Jamforthelamb, now that you have the oscillator built you might need one of these. http://aronnelson.com/gallery/Richard-Boop-RLBJR65/SignalTracer


Richard

[Jamforthelamb]

Cool,
So does this give you a constant sound through the speaker + a probe so you can send audio through a circuit ?

JFTL

[RLBJR65]

Send the oscillator signal through the circuit input, then use the tracer to follow it.

Richard