Qualifier - I'm not at home trying to troubleshoot transistor circuits. I spend more time working with tubes than semiconductors. I have no formal training. I'm a hobbyist that loves electronics and I'm probably older than most people here (58)

Prior to posting I did a little research and determined that each oscillator is a Common Emitter with Collector Feedback Bias circuit (unless it isn't )

I took some readings around Q1, R3, and R4.

Vcc = 9.0V
R3 = 150kΩ
R4 = 2.2kΩ
Collector Voltage 7.98V
Base to Emitter: 0.59V
Ie (if I did it right) is about 2mA
I used 100 for Hfe

That's about the end of what I could understand as far as checking the design goes. My intent was to try to analyze the oscillators by comparing actual to design but I have more ambition than I have knowledge.

The problem with the circuit is that it isn't oscillating. I've quadruple checked the components and they are correct. I've cross referenced my schematic with the author's schematic and they match. There are some idiosyncrasies with my Eagle schematic vs the original but they are the same for all intents and purposes. I had some boards made at Osh Park and I used surface mount components for all but the pots and the transistors so this isn't a stray capacitance / breadboard issue.

The transistors that I used are actually P2N2222A's. All other components are as noted. The circuit below is my Cadsoft Eagle version of the circuit located here:

 

Double check the lead identification of your P2N2222A transistors. These are different from 2N2222.
Post a photo of your board with components on it.

 

Remove R3 and R7 from collectors......connect to power rail. Put them sorta in parallel to R4 and R8.

 

I'm a hobbyist that loves electronics and I'm probably older than most people here (58)

Most of "the regulars" here are in the 55 to 75 range - I think we have a few pushing or past 80.

 

Hfe is 50 is for the 2222 and around 200-300 for the other transistor at 2 mA Ic. Not good.

 

Those are phase shift oscillators. The output at R9 can vary due to phase shift between oscillators.

If you reference the oscillators together......R9 should be consistent.

 

Nice! An active board! Thanks for all of the replies.

Photos:

My boards
Top

Bottom

Board file from Eagle. If I do it over I'll rotate the BNC 90° CCW and move some of the components.

I got the Hfe from an On Semiconductor data sheet for the PN2222A.
I mistakenly wrote P2N2222A in the first post

More than likely I read the datasheet wrong but here it is anyway (and there's a link above)

 

Update- I connected it to an HP 8903B audio analyzer and the signal, into the high input, is only .03mV with 12VDC power to the board. It variates with the volume and balance pot. My SA doesn't go low enough in frequency to measure the waveform, if there is one.

The intent of the board is to generate a pair of tones into the microphone line of an SSB transceiver ahead of the audio amp circuit. Could it be that the level is too low to measure with an oscilloscope? I'm using a Tek 2465B at 2mV/ div. (lowest setting). The output as measured is only 0.2% of span.

 

The transistors are fitted incorrectly. Looking at the flat side with the legs downwards the order is E, B, C. On your board they fitted 180 degrees out so the emitter and collector are swapped.

 

The transistors are fitted incorrectly. Looking at the flat side with the legs downwards the order is E, B, C. On your board they fitted 180 degrees out so the emitter and collector are swapped.

If I had a dollar for every time I looked at the transistor orientation I would have a lot of counterfeit dollars... How does one look at something like that so many times and not see it? I was all set to post a photo for you to see that they were installed right and they simply aren't. Thank you

I'll swap them and report back

 

I didn't swap the transistors, I replaced them and installed them correctly. Poof... like magic... it works as it should. I don't know how I missed that they were in backwards. I looked dozens of times. Oh well... I have proven that transistors are not ambidextrous...

 

I can't figure out how to attach the Cadsoft Eagle Files. I'm probably too new here for that priviledge. The circuit works as designed. The board layout could probably be improved but that works too. If someone wants the files just PM me and I'll email them to you in a zip file (79k)

 

The case of the extension might matter. .ZIP VS .zip. The forum may find .zip, but not .ZIP. Sometimes .zip.txt will work too.

 

The case of the extension might matter. .ZIP VS .zip. The forum may find .zip, but not .ZIP. Sometimes .zip.txt will work too.

Could be. When I hit the Upload a File button nothing happens. Considering my skills at installing transistors backwards perhaps it's something I'm doing wrong?

 

Try 2 things:

1. Under "Your account" Preferences, Disable the Flash based uploader
2, Make sure what your trying to upload has an all lower case extension.

 

It was the flash uploader. I have a Mac and for some reason flash has not been working. It doesn't need an update, etc, etc. Probably a new apple "feature". ttag.zip is attached

Personally I would either rotate the BNC, remote mount the BNC, and/or remote mount the pots if I made another one

Osh Park - https://oshpark.com/shared_projects/WGj3x4UT

There are cheaper places to get boards but they do nice work

 

Flash never works! and hasn't for many many years. Since the new Flash i have many Flash crashes per day.
Adobe has no interest in fixing it on Rogue operating systems except Windows and phone OS's

 

Remove R3 and R7 from collectors......connect to power rail. Put them sorta in parallel to R4 and R8.

Re: moving resistors
I say leave them where they are. The design works just as it is shown. Building each circuit individually (one step at a time) the oscillator works. The only changes I made was using a 2N3904 and running from +10 V.
Next step I will add the second oscillator, then connect them together.
But if I move the resistor as suggested it doesn't oscillate.

(edited to add ...)
Took a nap. Finished building the rest of the circuit. Works fine. One pot selects how much of each signal is selected. The other is total volume control. I can't tell what it sounds like. I don't have an audio amplifier on my breadboard, but I can see the waveforms.